Coffee is a brewed drink prepared from the roasting of coffee beans, which technically, are seeds of berries produced by the Coffea plant. Specifically, when Coffea plant berries ripen, they are picked, processed, dried, roasted, ground, brewed with boiling water, and served as the beverage we’ve come to know as coffee. Although the Coffea plant is native to tropical African countries such as Madagascar and Mauritius, it was long exported and is currently cultivated in upwards of 70 countries across the world, perhaps most notably: Brazil, Vietnam, Colombia, Indonesia, and Ethiopia.
Estimates suggest that upwards of 80% of adults in the United States consume coffee at an average rate of 3 cups per day, translating to a total of 587 million daily cups per day, and a $30-billion-dollar annual industry. There are countless of reasons as to why coffee remains among the most popular beverages in the world, including: its ability to enhance health, its potential in disease prevention, its pleasant aroma/flavor, and its association with social behavior (e.g. going out for coffee with friends). That said, perhaps the most obvious reason people drink coffee is to attain a transient psychostimulant effect from its caffeine content.
This psychostimulant effect is known to enhance mental dexterity as well as increase physical energy. Due to the increase in physiologic stimulation derived from caffeine, some have questioned as to whether coffee may increase metabolic rate, suppress appetite, burn body fat, and ultimately, induce weight loss. For individuals who suspect coffee might generate a weight loss effect, it may be helpful to understand: possible mechanisms of its weight loss action and existing research analyzing the relationships between coffee intake and body weight – all of which are discussed in the article below.
How Coffee May Cause Weight Loss & Prevent Weight Gain (Possibilities)
There are many ways in which drinking coffee could induce or promote weight loss and/or prevent weight gain. Specifically, various constituents within coffee such as: caffeine, chlorogenic acid, N-methylpyridinium, theobromine, and theophylline – are known to modulate physiologic processes. The cumulative modulation exerted upon the consumer’s physiology by constituents of coffee is generally considered stimulatory, and this stimulation may: suppress appetite (reducing likelihood of food consumption), enhance cognition and self-regulation (making it easier to restrict calories), and bolster energy levels (providing motivation to exercise).
That said, there are other mechanisms of action beyond increased physiologic stimulation that may explain weight loss that’s attributable to coffee consumption. Other potential mechanisms by which coffee may promote weight loss include: gut bacteria modulation, hormonal modulation, metabolic rate increases, reducing reactive oxygen species (ROS), and lowering inflammation. As of current, it remains unclear as to whether one specific mechanism of coffee’s action is substantially more relevant for induction of weight loss than others.
Most would hypothesize that the stimulatory effect derived from coffee constituents (especially caffeine) is responsible for the bulk of weight loss that individuals attribute to coffee. Still, it is necessary to recognize that many other effects exerted by coffee constituents upon physiology may contribute, in varying respects [perhaps contingent upon the specific consumer], to weight loss associated with coffee consumption. Included below is a list of many potential mechanisms by which coffee consumption might induce weight loss.
Appetite suppression: For some individuals, drinking coffee will exert an anorectic effect whereby appetite becomes suppressed and fewer calories are consumed, ultimately leading to weight loss. Although appetite suppression has never been scientifically confirmed as a direct effect of caffeinated coffee, it’s not farfetched to speculate that certain individuals might experience a reduced appetite from coffee consumption. The alkaloidal constituents of coffee (e.g. caffeine) can modulate hormone levels, neurochemicals, and brain activity – each of which might inhibit appetite.
Perhaps a less debatable mechanism of appetite suppression from coffee consumption is that drinking coffee might trick the brain into thinking that the stomach is full. Research suggests that drinking at least 2 cups of water before meals can suppress appetite enough to promote significant weight loss. Moreover, a study in females discovered that drinking at least 1.5 L of water per day beyond the RDA (recommended daily allowance) can suppress appetite and promote weight loss.
Since there are virtually no calories in coffee (just like water), it’s reasonable to suspect that persons drinking moderate-to-large quantities of coffee per day (e.g. 3 to 5 cups), may exceed the normative RDA of water enough to experience weight loss. If the moderate-to-large quantities of coffee are consumed prior to meals, appetite suppression may be even more significant. While more research is needed to evaluate the relationship between coffee intake and appetite, it’s likely that enough coffee will yield a suppression effect.
Cognitive enhancement: There’s considerable research suggestive of the fact that coffee can enhance aspects of cognitive function. While we know that a psychostimulatory effect generated by alkaloidal constituents such as caffeine can bolster cognition, caffeine is not the only cognitive enhancer within coffee. Studies indicate that even decaffeinated coffee can enhance aspects of cognitive performance.
Assuming a person with average or below average cognitive performance derives a cognitive boost from coffee, this may improve higher-order functions such as self-discipline. It has been shown that coffee consumption releases dopamine within the prefrontal cortex, possibly explaining improvement in a subset of consumers’ ability to exercise self-discipline when necessary. Greater self-discipline should make it easier for coffee drinkers to make healthier food choices and consume fewer total calories.
Energy increase: Due to the psychostimulant effect of constituents such as caffeine, theophylline, and theobromine – most individuals will feel more energetic after drinking coffee. The caffeine within coffee acts as an adenosine receptor antagonist whereby it blocks the neurotransmitter adenosine from binding to receptor sites. The blockade of adenosine binding is understood to counteract fatigue by increasing alertness, vigilance, and overall energy.
Both theophylline and theobromine within coffee can stimulate the heart rate, and the latter can enhance blood flow – which may complement caffeine in terms of increasing energy. It should be noted that an increase in energy after drinking caffeine does not magically induce weight loss by itself. However, a coffee-induced energy increase makes it easier for consumers to summon the necessary motivation to engage in physical exercises such as jogging, weight lifting, walking, etc.
Furthermore, greater energy after drinking coffee provides sufficient endurance needed to complete a workout and/or allows for increased exercise intensity. Predictably, if this energy increase is properly channeled towards exercise, more calories will be burned throughout the day – leading to weight loss. Research supports the idea that ingestion of caffeine (a constituent of coffee) prior to aerobic exercise can accelerate fat loss.
Fat oxidation: For reference, fat oxidation is the process by which stored lipids throughout the body are metabolized into smaller constituents, triglycerides and fatty acids, to provide energy. A study by Acheson, Zahorska-Markiewicz, Pittet, et al. (1980) discovered that coffee and caffeinated beverage intake significantly increases fat oxidation, and correspondingly, plasma free fatty acid concentrations. In the aforementioned study, free fatty acid concentrations nearly doubled within a 3-hour post-coffee consumption window.
That said, increased fat oxidation as a result of coffee consumption was only observed among persons exhibiting normative body weights – and was not observed among those who were overweight and/or obese. Considering this finding, it’s reasonable to suspect that, if a person’s body weight is relatively normal [by medical standards], drinking coffee might increase fat oxidation. Increases in fat oxidation as a result of drinking coffee should make it easier for individuals to lose body fat.
Logically, the loss of body fat should translate into some weight loss, however, among individuals with a high percentage of lean body mass and/or minimal body fat, the weight loss via fat oxidation may be modest or negligible. Moreover, even if weight loss attributable to coffee-induced fat oxidation is insignificant, many might notice improvements in physical appearance due to increased fat loss.
Gut bacteria: Some evidence suggests that coffee consumption can alter the composition of a person’s gut microbiome, which in turn, may directly and/or indirectly modulate physiologic processes to induce weight loss. First worth mentioning is a trial conducted by Jaquet, Rochat, Moulin, et al. (2009) in which drinking 3 cups of instant coffee per day for a 3-week duration significantly increased concentrations of Bifidobacterium species in fecal samples of healthy adults. This trial supports the hypothesis that regular consumption of coffee alters concentrations of gut bacteria, perhaps predominantly via upregulation of Bifidobacterium.
Preliminary research suggests that modulation of gut bacteria yields downstream changes in: antioxidant production, autonomic nervous system (ANS) activity, brain activity (e.g. blood flow, neurochemistry, regional function, etc.), gastric motility, hormone secretion, etc. This considered, it’s possible that the cumulative physiologic effect derived from coffee-induced microbial changes could induce weight loss and/or augment existing weight loss efforts. Interestingly, a review paper by Mekkes, Weenen, Brummer, and Claassen (2014) documenting that the specific Bifidobacterium species, “Bifidobacterium lactis Bb12,” may be efficacious as a probiotic supplement in reducing body weight, body fat, and weight gain.
Researchers believe that this particular bacterial strain attenuates low grade inflammation and lowers short-chain fatty acid (SCFA) levels whereby it becomes easier for people to lose weight. Assuming coffee intake substantially increases Bifidobacterium [lactis] strains in the gut, it’s possible that weight reduction effect similar to that discussed by Mekkes, Weenen, Brummer, and Claassen may occur. Moreover, while further research is needed to determine how coffee (especially different types of coffee) affects gut bacteria, as well as whether coffee-induced modulation of gut bacteria is conducive to weight loss – modulation of gut bacteria via coffee ingestion warrants consideration as a potential mechanism of coffee’s action in respect to weight reduction.
- Source: https://www.ncbi.nlm.nih.gov/pubmed/19217682
- Source: https://www.ncbi.nlm.nih.gov/pubmed/23886977
Hormonal modulation: Coffee is understood to modulate the secretion of various hormones and biomarkers, which in turn, could increase likelihood of weight loss. Examples of hormones and/or endogenous chemicals that coffee appears to modulate include: adiponectin, fetuin-A, insulin, leptin, and peptide YY. Coffee-induced adiponectin increases may prevent fat accumulation and/or enhance fat oxidation which leads to weight loss.
Reductions in fetuin-A concentrations post-coffee consumption may help counteract chronic inflammation and insulin resistance to augment weight loss efforts. Modulation of insulin secretion after drinking coffee may help counteract insulin sensitivity, and have downstream effects on other hormones whereby it becomes easier to lose weight. Moreover, reducing leptin among individuals who are overweight/obese may help offset leptin-induced leptin resistance and restore leptin sensitivity, ultimately making it easier to feel satiated after a meal and lose weight.
As of current, the extent to which each of the aforementioned hormones and/or endogenous chemicals may be implicated in coffee-induced weight loss remains unknown. It’s possible that coffee-induced modulation of one hormone (e.g. leptin) may play a more substantial role than others in the facilitation of a weight loss effect. It’s also possible that a myriad of post-coffee hormonal alterations synergistically influence physiology promote weight loss.
Yet another possibility is that the most beneficial effect of coffee upon hormones in respect to weight loss is individualized. One person might derive more weight loss benefit from coffee-induced insulin modulation, whereas another may benefit more from coffee-induced PYY increases. Finally, it is necessary to acknowledge that coffee may modulate hormone systems that haven’t been researched in terms of how they react to coffee intake.
Adiponectin: Adiponectin is a collagen-like protein that is synthesized in adipose tissue (even adipose tissue within bone marrow) and is a product of the gene apM1. It is known to circulate at high concentrations within human serum and its concentrations seem to correlate well with medical conditions. Generally speaking, the lower a person’s adiponectin levels, the greater the likelihood he/she is to exhibit: coronary artery disease (CAD), dyslipidemia, insulin resistance, obesity, and type 2 diabetes.
Some evidence suggests that coffee can increase circulating adiponectin concentrations, possibly a mechanism by which it promotes weight loss. For example, a randomized controlled study by Wedick, Brennan, Sun, et al. (2011) conducted among 45 overweight volunteers discovered that consumption of instant coffee at a dose of 5 cups per day for an 8-week duration significantly increases adiponectin concentrations from baseline [by approximately 1.4 mcg/mL]. This confirms that coffee can significantly increase adiponectin in a subset of persons, perhaps explaining favorable metabolic changes and corresponding weight loss observed in coffee drinkers.
Other research by Yamashita, Yatsuya, Muramatsu, et al. (2012) discovered statistically significant positive correlations between coffee consumption and adiponectin levels in a sample of 3317 Japanese workers. An investigation by Mure, Maeda, Mukoubayashi, et al. (2013) also discovered that light (1-3 cups per day) and moderate (4+ cups per day) coffee consumption is positively correlated with total serum adiponectin levels. Moreover, adiponectin concentrations were inversely associated with levels of visceral fat, suggestive of the fact that coffee may increase adiponectin to prevent fat accumulation and corresponding weight gain.
Some suspect that adiponectin may also elicit direct or indirect effects within the brain to promote weight loss. Research by Qi, Takahashi, Hileman, et al. (2004) report that adiponectin acts in the brain (as evidenced by cerebrospinal fluid elevations after intravenous administration) to upregulate expression of hypothalamic CRH (corticotrophin-releasing hormone) which stimulates energy expenditure to promote weight loss. Other research by Spranger, Verma, Göhring, et al. (2006) suggests that adiponectin does not cross the blood-brain-barrier (BBB), however, it alters the expression of cytokines within brain endothelial cells (e.g. decreases interleukin-6) which might affect energy metabolism and hunger. Overall, any coffee-induced increases in adiponectin may explain weight loss attributable to coffee consumption.
- Source: https://www.ncbi.nlm.nih.gov/pubmed/21914162
- Source: https://www.ncbi.nlm.nih.gov/pubmed/23169586
- Source: https://www.ncbi.nlm.nih.gov/pubmed/23602227
- Source: https://www.ncbi.nlm.nih.gov/pubmed/15077108
- Source: https://www.ncbi.nlm.nih.gov/pubmed/16380487
Fetuin-A: Fetuin-A is a serum protein manufactured by the liver and placenta that is implicated in bone metabolism, vascular function, and inflammation. Research indicates that fetuin-A is an endogenous inhibitor of the insulin receptor tyrosine kinase whereby it can induce whole-body insulin-resistance. Elevated levels of fetuin-A have been linked to dyslipidemia, inflammation, obesity, and type 2 diabetes.
Some evidence suggests that coffee consumption can significantly reduce concentrations of fetuin-A, possibly another mechanism by which it promotes weight loss. A randomized controlled trial by Wedick, Brennan, Sun, et al. (2011) discovered that coffee consumption at a dose of 5 cups per day for an 8-week duration reduced fetuin-A concentrations by 20%. Assuming coffee consumption leads to a reduction of fetuin-A, this may attenuate chronic inflammation and insulin resistance resulting from elevated fetuin-A, ultimately leading to weight loss.
- Source: https://www.ncbi.nlm.nih.gov/pubmed/21914162
Insulin: Insulin is a hormone manufactured by beta cells within the pancreas that modulates the metabolism of carbs, fats, and proteins by promoting absorption of blood glucose into fat cells, liver cells, and muscle cells. Cellular responses to insulin can determine whether an individual is more/less likely to feel satiated after consumption of food. If an individual develops insulin resistance whereby cells don’t respond normatively to the secretion of insulin, the energy from consumption of food remains unused, leaving the individual feeling hungry and possibly leading to excessive caloric intake.
Some evidence suggests that coffee consumption may favorably modulate insulin levels, which in a subset of persons, might promote weight loss. For example, a study conducted by Bidel, Hu, Sundvall, et al. (2006) with a sample of 12,287 persons discovered that coffee consumption was inversely associated with fasting insulin and glucose levels in both men and women. In other words, there was a positive relationship between coffee consumption, insulin sensitivity, and glucose regulation.
If coffee consumption favorably modulates insulin secretion, this may improve the efficiency by which blood glucose is absorbed into cells to provide energy. In turn, this would help increase energy levels, satiation, and normalize blood glucose concentrations – all of which could induce weight loss. As of current, more research is needed to determine whether coffee significantly modulates insulin, however, this may be implicated as a mechanism by which coffee induces weight loss.
- Source: https://www.ncbi.nlm.nih.gov/pubmed/16477539
- Source: https://www.ncbi.nlm.nih.gov/pubmed/21631956
Leptin: Leptin is a hormone secreted by adipose tissue that regulates energy balance by signaling to the medial hypothalamus that adequate fat has been stored from food consumption. When leptin signaling is functioning as intended, individuals feel full and have an easier time resisting excessive caloric intake. However, individuals who are overweight and/or obese tend to have excess body fat in their cells, and predictably, high levels of leptin, yet they remain hungry due to leptin resistance whereby the hypothalamus doesn’t receive adequate signaling from leptin that fat has been stored.
Because of leptin resistance, individuals don’t feel satiated and it becomes difficult to cease overeating behavior. Interestingly, one of the underlying causes of leptin resistance and corresponding weight gain is high levels of leptin. Some research, such as a study by Yamashita, Yatsuya, Muramatsu, et al. (2012), reveals a significant correlation between coffee consumption and lower levels of leptin.
If coffee consumption somehow reduces leptin concentrations and/or protects against abnormally-high leptin levels, perhaps this would reverse leptin resistance and restore leptin sensitivity. Moreover, if coffee regulates insulin secretion, this may have downstream effects on leptin levels whereby leptin sensitivity is restored. Restoration of leptin sensitivity from coffee consumption should help individuals feel satiated after consuming food, possibly leading to decreased caloric intake and weight loss. While it cannot be known whether coffee actually normalizes leptin signaling, this may be another means by which coffee [indirectly] promotes weight loss.
- Source: https://www.ncbi.nlm.nih.gov/pubmed/23169586
- Source: https://www.ncbi.nlm.nih.gov/pubmed/24752775
Peptide YY: Peptide YY (PYY) is a peptide secreted peripherally (within the gastrointestinal tract) and centrally (within the brainstem) following the consumption of food whereby its signaling yields an anorectic effect to suppress appetite. It is hypothesized that overweight/obese individuals exhibit suboptimal PYY secretion and/or impaired PYY signaling, and as a result, this leads to overeating. Preliminary research involving PYY injections 2 hours prior to a buffet lunch discovered reductions in total caloric intake by 30% in obese and 31% in non-obese persons, supporting the fact that PYY helps reduce hunger.
Although the data remain fairly ambiguous regarding whether PYY secretion is impaired among overweight/obese persons, it remains clear that increasing PYY concentrations attenuates appetite and corresponding caloric intake. Interestingly, some evidence indicates that certain types of coffee may increase PYY levels, possibly another means by which coffee promotes weight loss. For example, a small randomized, single-blinded, controlled study by Greenberg and Geliebter (2012) discovered that decaffeinated coffee significantly reduced hunger compared to a placebo for 90 minutes post-consumption.
Hunger reductions in the aforementioned study were directly correlated with significant increases in plasma PYY concentrations. While more research is needed to determine whether certain types of coffee legitimately increase PYY concentrations, it is a possibility to consider. If it turns out that various types of coffee (e.g. decaffeinated) facilitate a spike in PYY levels, it’s reasonable to suspect that appetite plus corresponding caloric intake will diminish, and weight loss will ensue.
- Source: https://www.ncbi.nlm.nih.gov/pubmed/23204152
Inflammation reduction: It is well-documented that there’s a bidirectional relationship between inflammation and weight gain such that: inflammation causes weight gain and weight gain causes inflammation; it’s vicious circle. Inflammation is understood to exert deleterious effects upon physiology whereby it can cause: hormonal dysregulation (e.g. insulin, leptin, et al.), microbiota irregularities, mitochondrial dysfunction, neurochemical imbalances, oxidative stress, and more – all of which promote weight gain and interfere with weight loss. That said, when inflammation is reduced, inflammation-related physiologic abnormalities are ameliorated and it becomes easier to lose weight.
One way in which drinking coffee might help some individuals lose weight is through exertion of an anti-inflammatory effect whereby inflammatory biomarkers are reduced. Support for an anti-inflammatory effect of coffee can be derived from an investigation by Kempf, Herder, Erlund, et al. (2010) in which coffee consumption significantly reduced subclinical inflammation. Other research by Lee, Im, Woo, et al. (2013) revealed that coffee constituents (e.g. eicosanoyl-5-hydroxytryptamide (EHT)) can bolster neuronal integrity and counteract neuroinflammation in animal models, as well as facilitate a direct anti-inflammatory effect via modulation of NFκB activation, iNOS induction, and nitric oxide production.
Moreover, research by Loftfield, Shiels, Graubard, et al. (2015) discovered significant associations between heavy coffee consumption and lower circulating IFNγ, CX3CL1/fractalkine, CCL4/MIP-1β, sTNFRII – suggesting that coffee might directly counteract inflammation. It is also known that coffee can modulate adiponectin, fetuin-A, and gut microbes – each of which can influence inflammatory processes. Assuming coffee is able to induce an anti-inflammatory effect, it’s reasonable to suspect that this could promote weight loss.
In fact, a paper by Sears and Ricordi (2011) highlights the therapeutic potential of anti-inflammatory nutrition in counteracting the physiologic inflammation that’s implicated in weight gain. Specifically, reducing inflammation via nutritional interventions (one of which might be coffee) may recalibrate hormones and genetic expression to mitigate excessive hunger, inhibit weight gain, and aid in weight loss.
- Source: https://www.ncbi.nlm.nih.gov/pubmed/20181814
- Source: https://www.ncbi.nlm.nih.gov/pubmed/23296837
- Source: https://www.ncbi.nlm.nih.gov/pubmed/25999212
- Source: https://www.researchgate.net/publication/47450638
Metabolic rate: Metabolism is the process by which your body converts the foods you consume into energy for various physiologic functions. Even when you’re sedentary or resting, your body is constantly utilizing energy stores for things like: respiration, circulation of blood, hormonal adjustments, and cellular repair. The number of calories your body uses to complete the aforestated physiologic functions is referred to as basal metabolic rate (BMR).
It is estimated that a person’s BMR accounts for nearly 70% of the calories burned in any given day. A lower BMR indicates fewer calories burned at rest, whereas a higher BMR indicates more calories burned at rest. Evidence suggests that coffee, in particular its caffeine content, could significantly increase BMR, which in turn, might promote weight loss. For example, a study by Acheson, Zahorska-Markiewicz, Pittet, et al. (1980) reported that consumption of coffee [containing 4 mg/kg caffeine] significantly increased metabolic rate in recipients – regardless of body weight.
Despite the finding that consumption of caffeinated coffee can increase BMR, the extent to which a coffee-induced BMR increase contributes to weight loss isn’t known. Furthermore, it remains unclear as to whether a BMR increase is maintained over a long-term with consistent coffee consumption – or whether it may diminish with tolerance onset to caffeine. That said, any increase in BMR from coffee consumption should be suspected as involved in coffee-induced weight loss.
- Source: https://www.ncbi.nlm.nih.gov/pubmed/7369170
Neurotransmission: Among those who experience weight loss from coffee consumption, the primary underlying mechanism of its weight loss action involves modulation of central neurotransmission. Caffeine, the chief psychoactive constituent of coffee, functions predominantly as a nonselective adenosine receptor antagonist whereby it inhibits receptor activation. The inhibition of adenosine receptor activation (e.g. A2A and A1) upregulates sympathetic tone and physiologic arousal, leading [many] coffee consumers to experience enhanced vigilance, energy, motivation, and/or self-control.
Enhanced vigilance, energy, motivation, and/or self-control should make it easier to restrict calories and/or engage in physical exercise – especially among persons making a concerted effort to lose weight. Moreover, research suggests that caffeine’s antagonism of striatal adenosine A2A receptors yields a downstream enhancement of dopaminergic signaling, some of which might facilitate appetite reduction and/or post-meal satiation – ultimately contributing to a weight loss effect. In addition to its antagonism of adenosine receptors and dopaminergic signaling, caffeine modulates an array of other neurotransmitter systems, including: acetylcholine, GABA, glutamate, histamine, norepinephrine, and serotonin.
It’s possible that the effect of caffeine [within coffee] upon all neurotransmitter systems with which it interacts leads to a cumulative physiologic change that is conducive to weight loss. That said, most evidence suggests that the bulk of caffeine’s weight loss effect stems from its ability to increase central excitatory neurotransmission, particularly of catecholamines (dopamine, epinephrine, norepinephrine). An animal model study by Chen, Lin, Song, et al. (1994) discovered that the administration of caffeine (4 mg/day for 4 weeks) significantly enhanced central norepinephrine and epinephrine signaling in obese mice, leading to reductions in body fat – likely through activation of the sympathetic nervous system.
The researchers noted that in the absence of caffeine administration, obese mice exhibited deficits in catecholaminergic transmission compared to non-obese mice. However, post-caffeine administration, obese mice exhibited catecholaminergic transmission analogous to non-obese mice, suggestive of the fact that sympathetic nervous system deficits may be causally implicated in obesity. In the obese mice, caffeine appeared to restore sympathetic function, thereby enabling fat loss and weight loss.
Related to the aforementioned animal research are findings from human studies indicating significant differences in neurotransmission between normal/healthy weight persons and overweight/obese individuals. For example, neuroimaging studies have reported impaired dopaminergic transmission in various areas of the brain [associated with reward and self-regulation] among persons with obesity – compared to non-obese adults. It’s possible that impaired dopaminergic transmission might interfere with self-control [around food] and/or leave individuals feeling unsatiated [around food] – leading to excessive caloric intake and weight gain.
Moreover, research by Mowers, Uhm, Reilly, et al. (2013) reported that individuals with obesity exhibit catecholamine resistance due to activation of PDE3B [as a result of inflammation], which in turn, can reinforce weight gain and/or inhibit weight loss. In any regard, anyone who is overweight and/or obese may find that coffee ameliorates neurochemical abnormalities that are interfering with existing weight loss efforts, particularly those of catecholaminergic origin. As a result of enhanced and/or normalized catecholamine signaling, it becomes easier to exercise (due to greater energy) and restrict calories (due to lower appetite, post-meal satiation, and self-control).
Even among persons who aren’t overweight, caffeine’s effect upon neurotransmission should be sufficient enough to induce physiologic adaptations that are conducive to weight loss. If your catecholaminergic signaling is already healthy, coffee can give it an additional boost to ramp up the physiologic changes associated with weight reduction. In summary, most of coffee’s weight loss effect is a byproduct of neurochemical [and corresponding physiologic] changes induced by its psychoactive constituents, principally, caffeine.
- Source: https://www.ncbi.nlm.nih.gov/pubmed/8242688
- Source: https://www.ncbi.nlm.nih.gov/pubmed/8039038
- Source: https://www.ncbi.nlm.nih.gov/pubmed/24368730
Replacement of meals and/or drinks: Another way in which some individuals might lose weight as a result of coffee is by deliberately (or perhaps unknowingly) using it as a meal replacement. For example, someone trying to lose weight may consciously decide to replace his/her breakfast with coffee. Assuming the individual had previously been consuming approximately 800 calories per day for breakfast, replacing breakfast with unaltered coffee [while keeping calories at lunch and dinner consistent with prior intakes] will eventually result in weight loss.
It should be noted that others may take up the habit of drinking unaltered coffee on a daily basis and notice that they feel somewhat full and/or that their appetite is lower post-consumption. Even without strategically planning to replace a meal with coffee for weight loss, a subset of these individuals may unconsciously do it anyways and realize that they’ve lost weight. It should also be mentioned that using coffee to replace a meal such as breakfast may lead to an extended “intermittent fast” and/or set up a time-restricted feeding schedule (e.g. from 12 PM to 8 PM), each of which have been associated with physiologic changes conducive to weight reduction.
While not everyone replaces meals with coffee, some will replace unhealthy, calorically-dense, hormone-altering beverages with coffee, ultimately leading to weight loss. For example, individuals with a habit of drinking sodas or fruit juices in the morning may decide to use coffee as a replacement. Assuming no other dietary adjustments, if a person replaced 3 sodas or 3 cups of fruit juice per morning with a few cups of coffee, he/she will be cutting approximately 450 calories or 408 calories, respectively, from his/her daily total caloric intake.
Not only is the reduction of total daily caloric intake significant for weight loss, hormones respond markedly different to coffee than sodas and fruit juices. Consuming soda or juice can lead to a transient blood sugar spike, followed by a crash characterized by low energy, foggy thinking, and food cravings – each of which make it easier to gain weight. Avoiding a sugar crash and attaining favorable hormonal modulation from coffee should help a person maintain cognitive function, self-control, and minimize food cravings to promote weight loss.
In fact, the idea that replacement of other beverages with coffee can induce weight loss is substantiated by preliminary research. A review by Dennis, Flack, and Davy (2009) documented that energy-free beverages such as coffee may facilitate weight management if substituted for energy-containing beverages. The review noted that consumption of coffee in its unaltered form contributes fluid to the diet without calories and is associated with significantly less weight gain over time in both men and women than consumers of other beverages.
- Source: https://www.ncbi.nlm.nih.gov/pubmed/19778754
Oxidative stress reduction: Elevated markers of oxidative stress are generally observed among persons who are overweight and/or obese, leading many researchers to suspect that oxidative stress causes and/or reinforces weight gain, at least in a subset of the population. A paper by Furukawa, Fujita, Shimabukuro, et al. (2004) indicates that systemic oxidative stress is positively correlated with fat accumulation in humans and mice. However, when exogenous antioxidants are administered to mice, concentrations of reactive oxygen species decrease and total antioxidant capacity increases.
There are many causes of oxidative stress including: chemicals, environmental toxins, excessive caloric intake, gene expression, inflammation, lipid-rich diets, micronutrient deficiencies, mitochondrial respiration, and sedentary lifestyle. A potential strategy for ameliorating oxidative stress and corresponding overeating behaviors and/or weight gain may involve regular consumption of coffee. The idea that coffee could ameliorate oxidative stress is supported with data from a randomized controlled trial conducted by Agudelo-Ochoa, Pulgarín-Zapata, Velásquez-Rodriguez, et al. (2016).
In this trial, plasma antioxidant capacity significantly increased in healthy adults who received coffee over a period of weeks – compared to a control group. A more specific link between coffee consumption, antioxidant capacity/oxidative stress, and weight loss is reported in a study by Kotyczka, Boettler, Lang, et al. (2011). The aforementioned study compared the antioxidant effect of dark roast and light roast coffee in volunteers, discovering that consumption of cark roast coffee (containing greater N-methylpyridinium) significantly increased concentrations of antioxidants such as tocopherol and glutathione as compared to the light roast.
What’s more, participants in the study who were characterized as “pre-obese” experienced weight loss after consuming the dark roast coffee for 1-month, yet this effect was not observed after consuming the light roast coffee. Based on this result, it’s reasonable to speculate that the increased antioxidant capacity [as a result of dark roast coffee] was conducive to weight loss. Assuming coffee reduces oxidative stress via enhancement of total antioxidant status, this may be an overlooked mechanism by which coffee induces weight loss.
- Source: https://www.ncbi.nlm.nih.gov/pubmed/26843588
- Source: https://www.ncbi.nlm.nih.gov/pubmed/15599400
- Source: https://www.ncbi.nlm.nih.gov/pubmed/21809439
Side effects: Not every person who drinks coffee finds it extremely tolerable without side effects. In the event that someone experiences noticeable side effects from his/her coffee consumption, it’s reasonable to suspect that certain side effects could facilitate to weight loss. Examples of coffee side effects that might induce weight loss include: bloating, diarrhea, frequent urination, gastrointestinal distress, headaches, nausea, stomach aches, and vomiting. Below is a brief description of the aforestated coffee side effects in regards to how each might facilitate weight loss.
- Bloating: Coffee can cause bloating in a subset of drinkers whereby the stomach or gut expands with fluid. The bloating may be so uncomfortable that individuals may intentionally skip meals and/or avoid eating until it clears up. The skipping of meals and avoidance of food may lead to a calorie reduction and weight loss.
- Diarrhea: Coffee can stimulate bowel movements, and for some individuals, this may yield an extreme laxative effect accompanied by diarrhea. Frequent bowel discharge, or diarrhea, leads to impaired absorption of calories from food, thereby causing weight loss. More notably, diarrhea dehydrates the body and can lead to transient weight loss from a reduction in water weight.
- Frequent urination: Coffee can facilitate a diuretic effect whereby individuals experience frequent urination. Frequently urinating may lead to dehydration and temporary weight reduction from dehydration.
- GI distress: Coffee is acidic, and for some individuals, it can wreak havoc within the gastrointestinal tract – causing significant distress. If you experience GI distress from your coffee habit, this may reduce your appetite and/or desire to consume food, possibly contributing to calorie restriction and weight loss.
- Headaches: The stimulant constituents of coffee cause intracranial blood vessels to constrict, which for some individuals, may be significant enough to cause a headache. If the headache is severe enough and/or painful, it could affect a person’s appetite, possibly leading to lower calorie intake.
- Nausea: While most people won’t experience nausea from drinking coffee, those who drink an excessive amount may feel nauseous. Assuming a person regularly consumes large quantities of coffee and feels nauseous each time, the nausea will likely interfere with appetite, which may lead to weight loss.
- Stomach aches: Another side effect that’s related to bloating and GI distress that some individuals will experience after drinking coffee is stomach aches. If each time you consume coffee your stomach or abdominal region aches or is in pain, you may have an easier time resisting food to lose weight.
- Vomiting: In extreme cases, individuals may experience nausea followed by vomiting. Vomiting is an adverse reaction to coffee and will generally lead a person to cease his/her coffee consumption and visit the doctor. Nonetheless, if you vomit each time you consume coffee, you’re going to lose a bit of weight.
Keep in mind that if a person is losing a significant amount of weight from coffee-induced side effects, the weight loss is likely unsustainable and unhealthy. Also understand that some of the weight loss resulting from side effects (e.g. diarrhea-induced weight loss) may be transient due to the fact that side effects may diminish as a person’s physiology adapts to regular coffee consumption. Moreover, most individuals who experience severe and/or disconcerting side effects from coffee probably won’t continue drinking it, and therefore, any side effect-induced weight loss is likely to cease. In any regard, certain side effects, assuming they persist over an extended duration, may contribute to [modest] weight loss in a subset of coffee drinkers.
Thermic effect of food: The thermic effect of food (TEF) is referred to as the number of calories burned during digestion, absorption, and excretion of foods that exceed metabolic homeostasis. Assuming calorie intake remains consistent, consuming foods with a greater thermic effect should lead to modest increased caloric expenditure throughout the day. Additionally, a study by Crovetti, Porrini, Santangelo, and Testolin (1998) suggests that an increased thermic effect of food may provide greater post-meal satiation.
If the aforementioned findings are accurate, the combination of increased caloric expenditure and post-meal satiation derived from foods with a high thermic effect can lead to weight loss. Interestingly, it appears as though consumption of coffee can increase the thermic effect of food, possibly a mechanism by which coffee induces weight loss and/or inhibits weight gain. Specifically, research by Acheson, Zahorska-Markiewicz, Pittet, et al. (1980) discovered that consumption of coffee (containing 4 mg/kg caffeine) with a ~736 calorie meal significantly increased the thermic effect of the food.
The specific number of extra calories burned throughout the day due to coffee-induced increases in the thermic effect of food remain unknown. Furthermore, it is unclear as to whether greater post-meal satiation was experienced due to coffee consumption. That said, assuming coffee effectively increases the thermic effect of food, and that this effect is stable over a long-term – this should augment preexisting weight loss efforts.
- Source: https://www.ncbi.nlm.nih.gov/pubmed/9683329
- Source: https://www.ncbi.nlm.nih.gov/pubmed/7369170
Note: It is necessary to note that not everyone will experience weight loss from their coffee consumption. The aforementioned mechanisms by which coffee induces weight loss may only apply to a subset of the population. Moreover, it isn’t clear as to whether one specific mechanism of coffee’s action is more important than others in regards to the generation of a weight loss effect. It’s possible that one specific mechanism such as enhanced catecholaminergic signaling and sympathetic tone leads to more weight loss than another (e.g. changes in gut microbiota). That said, it’s also possible that many mechanisms contribute to the weight loss effect in some sort of hierarchy – perhaps subject to individual variation [in regards to the physiologic abnormalities that are inhibiting weight loss].
Variables that influence coffee-related weight change
There are many variables that can influence any weight change you might experience from coffee consumption. These variables include things like: the specific type of coffee you drink (e.g. dark roast), the amount you consume (e.g. 200 ml), the regularity of your consumption (e.g. daily), cumulative duration of your consumption (e.g. 5 years), administration details (e.g. morning with breakfast), and individual factors (e.g. genetics). It is these variables that explain differing reactions to coffee in regards to its effect on weight.
It is necessary to realize that not all coffee will have the exact same effect upon body weight. When attempting to determine the effect of coffee on body weight, it is necessary to examine specific attributes of the coffee that a person regularly consumes. Specific attributes of coffee that might affect weight include: additives, coffee beans, cultivation details, contaminants, and preparation details. This is why switching from one type of coffee to another may have a noticeably different effect on your body weight.
- Additives: Many individuals add extra ingredients to their coffee to enhance its flavor, increase their satiety, and/or for [hypothesized] health benefits. Any ingredients that are added to coffee may contain a lot of calories to induce weight gain. Additionally, select coffee additives may affect the pharmacokinetics of coffee constituents (e.g. caffeine) whereby its physiologic effect is altered. Additives can also have a direct impact on post-consumption hormonal activity, possibly increasing and/or decreasing appetite and corresponding caloric intake. Popular coffee additives include: artificial sweeteners, butter, cinnamon, cream, milk, MCT oil, whipped cream, and sugar. To elaborate, as an example, someone who adds copious amounts of sugar and cream to their coffee should expect weight gain [due to hormonal changes, increased hunger, and ingestion of extra calories] over a long-term compared to a person who drinks coffee without additives. On the other hand, certain additives (e.g. medium-chain triglycerides) may increase satiety and promote fat oxidation, in which case, a subset of individuals may have an easier time losing weight with specific additives than without. Consider the additives to your coffee in terms of calorie content and physiological impact to determine how they might influence coffee’s effect on your weight.
- Brand: The particular brand of coffee that you purchase, as well as the company from whom you purchase it (e.g. directly from the company vs. third-party seller) may influence how it affects your physiology and ultimately determine whether you lose weight. Most coffee companies attain their beans from growing operations that are distinct from other companies, meaning the cultivation details associated with the beans (e.g. mechanical vs. hand-picked) will differ among companies – and ultimately, so will the constituents (e.g. paraxanthines). As a result, consuming “Arabica Dark Roast” from Brand “A” may yield different effects than consuming the same type from Brand “B.” Moreover, even if the differences in coffee beans among various coffee companies are modest, these modest differences may have markedly different effects on body weight when consumed over an extended duration.
- Coffee beans: The specific species of coffee beans that you consume could influence how coffee affects your body weight. Coffee beans are typically classified under one of several species, including: Arabica (coffea arabica) – 70% of all coffee on the market, Robusta (coffea canephora) – 27% of all coffee on the market, and Liberian (coffea liberica) – 3% of all coffee on the market. Upon comparison of constituents within the two most predominant species, it appears as though Arabica beans contain 1.2% caffeine and 5.5-8% chlorogenic acid, whereas Robusta beans contain 2.2% caffeine and 7-10% chlorogenic acid. Percentages of other coffee bean constituents such as theobromine, theophylline, and N-methylpyridinium – likely also differ due to species. These constituent differences, even if modest, might lead regular Robusta drinkers to lose more weight than Arabica drinkers over an extended timeframe.
- Cultivation details: Although the overarching species of coffee beans will determine the general coffee bean constituents, specific details associated with cultivation of the beans can also influence bean composition. Specific details to evaluate in terms of coffee bean cultivation includes: country of cultivation, land upon which beans were grown, weather patterns, and experience of persons harvesting the beans. Arabica coffee beans harvested in Brazil will likely contain different constituents that the same species of beans harvested in China. In addition, Arabica coffee beans cultivated on optimal land in ideal weather by experienced farmers (e.g. to ensure peak ripeness of the beans) will likely contain different concentrations of constituents than Arabica beans cultivated on suboptimal land by inexperienced farmers. All of the details associated with cultivation can affect bean composition and its corresponding effect upon your body weight after consumption. These cultivation specifics may explain why one Arabica coffee bean source (or vendor) seems to affect your weight and/or physiology differently than another.
- Contaminants: Certain companies take steps to minimize likelihood that their coffee beans are contaminated, whereas others don’t. In the event that the company from whom you purchase your coffee beans is lacking in quality assurance, you may end up consuming coffee beans that contain things like: chemical fertilizers, mycotoxins (e.g. OTA), pesticides (e.g. fungicides, herbicides, insecticides, etc.). While washing the beans and roasting them to sufficient temperatures can be helpful, they may not eliminate all contaminants. Hypothetically, if Person A regularly consumes coffee containing modest amounts of Ochratoxin-A whereas Person B regularly drinks coffee with no detectable Ochratoxin-A, it’s reasonable to think that Person A’s health and weight might suffer in comparison to Person B. Although most coffee won’t have high levels of contaminants, if coffee with modest levels of contaminants [that survive brewing] is regularly ingested, the long-term effects on body weight may be noticeable.
- Preparation details: The way in which your coffee is regularly prepared could also influence its effect upon your body weight. Details associated with coffee preparation include: equipment used for brewing, quality of the grind (i.e. consistency), quality of water added, brewing temperature, and cup in which it is served. A subset of coffee brewing amateurs may: use low quality brewing equipment, fail to adequately grind coffee beans, use [potentially contaminated] tap water, brew coffee at the wrong temperature (e.g. with boiling water), and/or serve coffee in a plastic cup [whereby plasticizers (e.g. BPA) leach into the coffee]. On the other hand, coffee brewing experts may: use high quality brewing equipment, grind beans optimally, use reverse osmosis water with remineralization, brew coffee at an optimal temperature, and serve it in stainless steel mugs. Even if the exact same brand of coffee is used, the final product served by the amateur may contain different levels of antioxidants, psychoactive constituents (e.g. caffeine), and/or toxins (e.g. lead from unfiltered water) – leading to altered physiologic effects and long-term weight changes.
Consumption: Dosage + Regularity
The quantity of coffee that you drink, as well as the regularity of your consumption will influence how it affects your weight. In general, the greater the average quantity of coffee you consume and the more regularly you consume it, the more substantial effect it’ll likely exert upon your physiology whereby it could induce weight loss. On the other hand, the lesser the average quantity of coffee you consume and the lower your frequency of consumption, the less likely it’ll affect your physiology enough to induce weight change.
- Dosage (average intake): Assuming that certain types of coffee can promote weight loss, the average amount a person consumes will influence the extent of the weight loss. If the average quantity of coffee that you consume is small (e.g. quarter cup), the constituents within coffee may not exert enough of an effect upon your physiology to promote noticeable weight loss. It’s possible that small doses of coffee do not surpass a necessary physiologic dosing threshold to help a person lose weight. That said, if the average quantity of coffee you consume is large, chances are that its physiologic effect could be significant enough to generate a weight loss effect. (Keep in mind that the significance of the physiologic effect of coffee will be partly contingent upon a person’s body size and composition).
- Regularity: In addition to quantity of consumption, the regularity or frequency of your consumption can influence how you’re affected by coffee. Even if large average quantities of coffee are consumed, infrequent consumption (e.g. once or twice a month) may not affect your weight. Those who consume coffee on an infrequent basis will never physiologically adapt to the effect of the coffee consumed. Even if weight loss via coffee consumption is attainable, infrequent dosing allows the body to revert back to homeostasis between doses, thereby negating any noticeable coffee-augmented weight loss. Someone who consumes coffee on a regular basis (e.g. daily) should expect a more profound effect of coffee upon physiological processes and body weight. Assuming average intake is large, there is likely a regularity of consumption threshold (e.g. 5 times per week) that needs to be met to facilitate weight loss.
Cumulative duration of intake
The total duration over which a person has consumed coffee could also influence whether weight loss is likely to: occur, continue, and/or diminish. Assuming you’re drinking large amounts of coffee on a regular basis, its effect upon physiology should be significant enough to potentially promote and/or induce weight loss. However, the weight loss that occurs from coffee consumption won’t be noticeable overnight – time will be needed before any coffee-induced weight change becomes noticeable.
In the event that a coffee-naïve individual began consuming 3-5 cups of coffee per day and tracked his/her body weight, it would probably take several weeks and/or multiple months before the habit of daily coffee consumption induced any reasonable weight loss (e.g. over a pound). Hypothetically, if a coffee habit induces weight loss over a moderate term, further changes in body weight may diminish and cease altogether due to physiologic tolerance. Moreover, maintenance of coffee intake over a long-term may even result in the regaining of initially-lost weight.
- Short-term: The consumption of coffee over a short-term such as several days or a couple weeks is unlikely to facilitate any noticeable weight change. As with any weight loss intervention (e.g. caloric restriction, dieting, exercising, etc.), weight loss from coffee consumption probably won’t occur within 1 or 2 weeks. That said, it’s possible that a subset of individuals will find coffee to be synergistic with other weight loss interventions (e.g. caloric restriction) such that weight loss occurs rapidly and is noticeable over a short-term.
- Moderate term: The consumption of coffee over a moderate-term [ranging from several weeks to a year] may yield some modestly-noticeable weight loss, especially if consumed on a daily basis in moderate-to-large quantities. A moderate-term of coffee consumption provides enough time for any coffee-induced weight loss to become noticeable. If your coffee habit facilitates weight loss of 0.25 lbs. per 2 weeks, this may be unnoticed over a short-term. That said, over a moderate-term, you may realize that you lost a pound or two. That said, since coffee doesn’t induce major weight loss, the amount of weight any given person should expect to lose over a moderate term probably won’t exceed a few pounds. If coffee consumption is combined with interventions such as exercise and caloric restriction for several months, then weight loss after a moderate-term should be more significant, however, the extent to which coffee will have helped reduce weight relative to the other interventions will remain unclear. Unless you carefully track your daily body weight and fat percentage, and keep diet plus exercise consistent, you may not even realize that you’ve lost weight from coffee over a moderate-term. Moreover, some individuals may hit a weight loss plateau after a moderate-term resulting from physiologic tolerance to coffee and/or reaching a low body fat percentage – ultimately inhibiting further weight loss.
- Long-term: The consumption of coffee over a long-term (e.g. years or decades) is unlikely to induce weight loss. If you lose weight from coffee consumption, most of the weight loss will have occurred over a moderate-term of months, not a longer-term of years. Long-term coffee drinkers will have developed physiological tolerance to coffee constituents and/or may have already maxed out their weight loss – each of which minimize odds of additional weight loss. The only scenario in which additional coffee-induced weight loss might occur after a long-term of regular consumption is if average daily intake is titrated upwards. For example, if after 2 years of drinking 1 cup of coffee per day the intake is increased to 4 cups per day, this can override physiologic tolerance whereby the effects of coffee that are conducive to weight loss become more noticeable. That said, if coffee intake is consistent, physiologic tolerance will occur and coffee will cease to induce weight loss. Furthermore, after tolerance development, any reduction in coffee intake (or cessation of coffee altogether) may cause fatigue, slowed metabolism, and/or increased appetite – each of which can lead to weight gain. Knowing that weight gain can occur from decreased coffee intake, continued regular consumption over a long-term should prevent discontinuation-related weight gain. Additionally, if someone has been strategically using coffee to replace meals (for calorie cutting) or to fuel physical exercise, perhaps over a long-term, regular coffee consumption prevents a resurgence of old unhealthy habits associated with weight gain – thereby aiding in weight maintenance. Still, some individuals might notice that they gain a bit of weight back over the long-term due to the fact that, after receptor density adjustments and tolerance onset, sympathetic tone reverts back to pre-coffee homeostasis whereafter effects conducive to weight loss such as: appetite reduction, metabolism increase, and energy boost – diminish.
The specific details associated with coffee consumption may influence the amount of weight loss that a person experiences from his/her coffee intake. Examples of such consumption details include: drinking speed (e.g. slow sipping), whether ingested on an empty stomach or with food, timing of administration (e.g. early morning), and temperature of the coffee (e.g. hot). It should be noted that modality of coffee administration may also influence its physiologic effect and weight loss potential, however, this article is focused on drinking coffee [via the mouth] – not enemas, intranasal insufflation [of beans], nor intravenous injections.
- Drinking speed: The speed at which you drink coffee can influence the duration and potency of its physiologic effect, and may determine whether you lose weight and/or the significance of weight loss that you experience from its consumption. Someone who drinks a cup of coffee as quickly as possible (e.g. in less than a minute) is more likely to receive a short-term, highly-potent jolt of energy – whereas someone who slowly sips a cup of coffee over a 1-hour is more likely to receive a less potent, yet longer-lasting energy boost. Research by White, Padowski, Zhong, et al. (2016) discovered that the speed of coffee consumption affects its pharmacokinetics, which in turn, could alter physiologic reactions attributable to weight loss. As of current, it remains unknown as to how rapid, moderate, and slow speeds of consumption compare in terms of weight loss induction. Given the fact that individuals vary in hepatic enzyme expression due to genetic polymorphisms, perhaps optimal speed of coffee consumption for weight loss is individualized. Then again, it’s also possible that there are no major differences in the long-term effect of coffee drinking speed on physiology. However, even if drinking speed has minimal effect on influencing physiology to promote weight loss, some individuals may find one drinking speed to be of greater psychological value than another. For example, someone may report that they have an easier time resisting the urge to eat or consume excess calories over an extended duration (e.g. an entire afternoon) if they slowly sip their coffee – compared to rapidly downing it. On the other hand, another person may report that drinking coffee rapidly provides a jolt of energy necessary to perform a high-intensity workout and burn a lot of calories – compared to slowly sipping.
- Food vs. empty stomach: Whether you drink coffee with food or on an empty stomach might also influence the significance of any weight loss derived from its consumption. Drinking coffee on an empty stomach is likely to yield slightly different pharmacokinetic parameters than if consumed after a large meal. Individuals drinking coffee on an empty stomach will likely absorb, metabolize, and excrete coffee constituents at a faster rate than persons who consume it during and/or after a full meal. Empty stomach consumption may yield a shorter-lived jolt of energy than full-stomach consumption. This is because the presence and digestion of food may delay and/or prolong the metabolism of coffee constituents, whereby the duration of effect is longer. It’s also possible that drinking coffee while eating (e.g. intermittent sipping between bites of food) yields slightly different pharmacokinetic and physiologic effects than if consumed in the immediate aftermath of a meal. Nonetheless, there are no definitive data regarding whether drinking coffee with food is superior to empty stomach intake for the induction of weight loss. If persons consuming coffee on an empty stomach find that it helps restrict calories more than consumption with food, empty stomach consumption would likely be the most effective weight loss strategy. Still, we must acknowledge findings from a study indicating that consumption of coffee with a meal significantly increases the thermic effect of food, and for a subset of persons, bolsters fat oxidation – potentially making “with food” consumption superior over empty stomach consumption for weight loss. That said, there are data to suggest that consuming zero calorie beverages (e.g. water) on an empty stomach prior to a meal often leads to reduced caloric intake and weight loss. For this reason, it should be acknowledged that empty stomach consumption of coffee prior to a meal may be a highly effective way to lose weight. The exact timing of coffee consumption in respect to a meal may also influence weight loss. Hypothetically, drinking coffee 1 hour before a meal may have a more/less significant weight loss effect than 5 minutes before a meal. Similarly, drinking coffee immediately after a meal may have a more/less significant weight loss effect than drinking coffee 20 minutes after a meal.
- Temperature: The temperature at which you consume your coffee could dictate whether you burn extra calories and/or lose more weight. A study by White, Padowski, Zhong, et al. (2016) discovered that consumption of hot coffee lead to a greater peak serum concentration than cold coffee. Considering these findings, we might suspect that greater peak serum concentration yields a more prominent physiologic effect whereby weight loss is more likely to occur. This would favor the idea that persons who keep their coffee as hot as possible (e.g. in a thermos) end up losing more weight from its consumption. Although not supported by science, anecdotal accounts suggest that consumption of a hot beverage is more filling and/or satiating than a colder one. Assuming hot coffee makes you feel full and/or quells your appetite, this should be conducive to weight loss. That said, it is known that when a person consumes a cold beverage, approximately 8 calories are burned by the body to warm it up. Drinking an iced coffee every day for a week might burn an extra 56 calories per week, and approximately 2912 calories per year – resulting in some [negligible] weight loss. Even if coffee temperature has an insignificant impact upon physiology as to induce weight loss, certain temperatures may be more conducive to weight loss on an individual basis. For example, one person might find that it’s easier to resist food cravings after a hot cup of coffee than an iced one; others may experience the opposite effect OR claim that coffee temperature is irrelevant in terms of appetite suppression. Nonetheless, it is reasonable to suspect that coffee temperature may affect drinking speed, another variable that influences pharmacokinetics. Generally, it is common for individuals to slowly sip hot beverages and drink lukewarm and/or cooler beverages at a faster rate, possibly yielding a less substantial physiologic impact for weight loss.
- Time of ingestion: The time at which you drink coffee may also influence whether you end up losing and/or gaining weight. For most individuals, drinking coffee in the morning is optimal because it doesn’t disrupt the circadian rhythm, and in some cases, it may correct/reset circadian abnormalities. If consumption of coffee in the morning normalizes a previously abnormal circadian rhythm, this should enhance cognitive function and energy levels, potentially augmenting preexisting weight loss efforts. Drinking coffee in the afternoon can sometimes disrupt the circadian rhythm, making it difficult to fall asleep at night. However, some may find that drinking coffee in the early afternoon doesn’t interfere with the circadian rhythm and helps them survive a mid-day energy crash that would’ve normally resulted in unhealthy snacking. Most individuals who drink coffee in the late afternoon or evening find that its physiologic effect disrupts the circadian rhythm, ultimately detrimentally affecting hormone production and neurochemical processes – leading to lower energy, an insatiable appetite, and impaired self-regulation around food – making it tougher to lose weight and/or inhibit weight gain. That said, if coffee in the evening makes it easier for you to restrict calories than consumption in the morning, and doesn’t negatively affect your circadian rhythm, it’s possible that this could yield weight loss. Lastly, it should be noted that optimal timing of coffee ingestion for induction of weight loss may differ from the general population among persons who’ve adapted to working “night shifts” (e.g. 11 PM to 7 AM).
In addition to variables such as the specific coffee consumed, its dosage, the frequency of its consumption, cumulative duration of its intake, and miscellaneous consumption details (e.g. temperature, timing, etc.), predicting whether someone loses weight from coffee consumption will be largely contingent upon individual factors. Individual factors such as a person’s: age, body composition, diet, drug usage, exercise habits, gene expression, medical conditions – will influence physiologic responses to coffee. Differences in physiologic responses to coffee explain why one individual may find coffee helps them lose a lot of weight, whereas another may find that coffee has no effect on body weight.
- Age: The effect of coffee’s constituents (e.g. caffeine) upon physiology may differ based on a person’s age and ultimately influence whether someone loses weight. Lopez-Garcia, van Dam, Rajpathak, et al. (2006) report that coffee induces weight loss in younger populations but not in older adults. There are many reasons as to why older individuals may not experience weight loss from coffee compared to younger persons. One reason might be that younger individuals, on average, have a greater number of naïve coffee drinkers and/or persons who haven’t yet developed physiologic tolerance – compared to older adults who’ve maintained a long-term habit over a span of years. If tolerance is less likely to have been established in younger persons, a noticeable weight loss effect should be expected. Moreover, perhaps the older adults have already lost the maximum amount of weight possible with coffee consumption and their tolerance to inhibits additional weight loss. It’s also possible that age-related differences in hepatic function and/or hormone production influence whether coffee is likely to aid in weight loss. For example, Zivković (2000) mentioned that elderly individuals are more likely to exhibit depleted hepatic enzymes, thereby compromising caffeine degradation and physiologic effects.
- Body composition: A person’s body size (height / weight) and composition (fat / muscle) may also influence whether weight loss occurs from coffee consumption. In general, larger individuals need to consume more caffeine for a prominent physiologic effect than smaller individuals. Perhaps this explains why larger individuals who consume a small amount of coffee each day may not be consuming enough [relative to their body size] to noticeably affect their physiology for induction of weight loss. To control for body weight in studies that analyze the effect of coffee on physiology, researchers usually administer a fixed-dose of caffeine within the coffee in accordance with the consumer’s body weight (e.g. 4 mg/kg). Nonetheless, this method may be somewhat flawed based on the fact that one person who’s 180 lbs. may be just 5’5” with a high percentage of body fat, whereas another may be 6’2” with minimal body fat and a lot of muscle. In any regard, your body size and composition relative to your coffee consumption will likely influence whether you lose weight, and if so, how much. Persons who are either underweight and/or of a low body fat percentage probably won’t experience weight loss from coffee due to the fact that they don’t have much extra weight to lose. Evidence from research suggests that persons most likely to lose weight from coffee consumption are either normal weight or overweight/obese. If you have minimal body fat and a lot of muscle, coffee probably won’t affect your weight unless you drink enough to induce muscle catabolism and lose muscle weight. Keep in mind that your body size and composition may dictate how efficiently your body absorbs, metabolizes, and excretes coffee – as well baseline hormones and/or hormonal secretion post-ingestion. The variation in body size/composition-mediated pharmacokinetics and hormonal interplay may also dictate the significance of your coffee-induced weight loss. Certain hormones might synergistically enhance or antagonistically attenuate the coffee-induced physiologic changes that are conducive to weight loss.
- Co-ingested substances: If you’re regularly using a pharmaceutical medication, illicit drug, dietary supplements, or frequently drink alcohol – there’s a chance these might affect the weight loss you experience from coffee consumption. For example, co-administration of a substance that is known to induce weight loss (e.g. topiramate) may act synergistically with coffee in the facilitation of weight reduction whereby more weight is lost with the combination than either as a standalone. Oppositely, co-administration of substances that are known to induce weight gain (e.g. olanzapine) may fully offset and/or override the weight loss effect of coffee whereby an individual ends up gaining weight on the combination. It is also possible that a co-administered substance is entirely weight neutral (e.g. a multivitamin). That said, in addition to potentiating or antagonizing weight loss effects, co-administered substances while drinking coffee may alter pharmacokinetics and/or pharmacodynamics of coffee constituents (e.g. caffeine); and vice-versa. Since caffeine is metabolized primarily by the CYP1A2 enzyme, any drug that induces or inhibits CYP1A2 will alter the impact of coffee upon physiology and corresponding weight change. It’s also possible that a co-administered substance either potentiates or offsets the neurochemical action of caffeine within the brain, yielding respectively more or less physiological stimulation to induce or inhibit weight loss.
- Diet: Generally speaking, if you aren’t carefully tracking your daily macronutrient and caloric intake, you’ll have no idea whether coffee is facilitating a weight loss effect. To accurately know whether coffee can induce weight loss, a person would need to consume the exact same foods, at the exact same times each day, and in the exact same quantities. This way, when coffee is introduced, a person will know whether the coffee itself is responsible for inducing weight loss via its physiologic effect. Another possibility is that induces weight loss directly via physiology and/or indirectly through suppression of appetite. In any regard, someone who consumes a caloric surplus every single day will gain weight over time – regardless of coffee consumption. The modest weight loss effect that may be attributable to coffee will not be enough to override excessive caloric intake. Additionally, we should consider the macronutrient and micronutrient quantities of a person’s diet. A person who eats a diet high in protein and fiber with plenty of micronutrients will likely exhibit differences in baseline physiology in terms of hormones, neurochemicals, etc. compared to a person who eats a diet high in carbohydrates and fat with micronutrient deficits. It is possible that the weight loss effects of coffee may be amplified, complemented, and/or attenuated due to macronutrient and micronutrient-mediated physiologic processes. For example, a high-protein diet can increase leptin sensitivity which can decrease appetite and lead to reductions in caloric intake, ultimately complementing the weight loss effect of coffee.
- Exercise: A person’s exercise habits may also influence the significance of weight loss derived from coffee consumption. On average, persons who regularly exercise exhibit faster resting metabolic rates and healthier biomarker profiles than those who are sedentary. The faster resting metabolic rates among active persons leads to greater caloric expenditure throughout the day whereby it becomes easier to lose weight. Additionally, the healthier biomarker profiles (e.g. antioxidants, cytokines, hormones, neurotransmitters, etc.) exhibited by active individuals may interact with the constituents of coffee (e.g. caffeine) differently than the [unhealthier] biomarker profiles exhibited by sedentary individuals, ultimately making it easier for active persons to lose weight from coffee consumption. In other words, there may be a synergistic effect between exercise-induced physiologic changes and coffee that is conducive to weight loss. That said, there are many different types of exercise, each of which elicit distinct hormonal responses. Someone who solely engages in walking will secrete different hormones than if he/she engaged in sprinting or powerlifting. Knowing this, it’s possible that the significance of weight loss a person experiences from coffee intake is partly contingent upon the specific type of exercise he/she performs [and its corresponding biomarker adjustments]. That said, it remains unclear as to whether one particular type of exercise yields biomarker changes that are more conducive to coffee-induced weight loss than another. Even if exercise-mediated biomarker changes fail to play a role in coffee-induced weight loss, research suggests that drinking coffee [approximately 1-hour] before a workout can significantly enhance performance. This enhanced performance may significantly bolster caloric expenditure [during workouts] and/or facilitate superior gains in lean mass – each of which could lead to quicker weight loss.
- Genetics / Epigenetics: A person’s genetic and epigenetic expression may influence whether they end up losing weight from coffee consumption, and if so, the amount that is lost. Arguably most significant genetic influencer of coffee upon physiology is expression of the CYP1A2 gene. The CYP1A2 gene is implicated in the hepatic metabolism of caffeine, and when its expression is atypical, the metabolism of caffeine is either expedited or prolonged – compared to the general population. Specifically, individuals carrying multiple copies of the CYP1A2*1A allele will metabolize caffeine rapidly, whereas persons carrying at least one copy of CYP1A2*1F will metabolize caffeine slowly. Interestingly, research suggests that persons with multiple copies of CYP1A2*1A derive significant health benefit from coffee consumption whereas persons with CYP1A2*1F tend to incur negative health effects. At this time, it is unclear as to whether coffee-induced weight loss might significantly differ between rapid (multiple CYP1A2*1A copies), extensive (standard CYP1A2 expression), and/or poor (CYP1A2*1F expression) metabolizers of caffeine. Nevertheless, it’s possible that CYP1A2 expression correlates and/or predicts likelihood of coffee-induced weight loss. Additionally, CYP1A2 expression may influence one’s propensity to consume more or less coffee (e.g. greater consumption among persons with multiple copies of CYP1A2*1A), ultimately affecting average dosage consumed. In addition to CYP1A2, expression of the ADORA2A gene might affect whether someone loses weight from coffee consumption. The ADORA2A gene encodes for adenosine receptor 2A expression, and variations can affect how sensitive someone is to caffeine. Someone with the T allele of ADORA2A may experience significant anxiety from caffeine, whereas someone with multiple copies of the C allele of ADORA2A may be more prone to sleep disturbances from caffeine. It’s possible that the physiologic impact of the caffeine within coffee as it pertains to weight loss is altered based on ADORA2A. Another gene to consider as a possible influencer of coffee-induced weight loss is COMT. The COMT gene encodes for Catechol-O-Methyl Transferase (COMT), an enzyme that’s implicated in the breakdown of catecholamines. Knowing that caffeine within coffee increases catecholamines (dopamine, epinephrine, norepinephrine) to facilitate physiologic arousal, genetic variations in COMT expression will determine the duration of physiologic arousal post-coffee consumption. Moreover, genes that are entirely unrelated to physiologic metabolism and/or reactions to caffeine within coffee might determine whether someone is able to lose weight from drinking coffee. Inheritance of a problematic genes that make it more difficult to resist food cravings, stay active, and/or lose fat – could interfere with coffee-induced weight loss. Inheritance of genes that may be conducive to weight loss (e.g. from fit ancestors) may increase odds of coffee-induced weight loss. Finally, a person’s epigenetic expression based on environmental factors might also influence odds of coffee-induced weight loss such that certain epigenetic signatures may be more conducive to weight loss than others.
- Medical conditions: Any medical conditions a person has could also dictate whether they lose weight from coffee consumption. Certain medical conditions are associated with weight gain and will make it challenging to lose weight – regardless of weight loss interventions. For example, hypothyroidism (underactive thyroid) can slow resting metabolic rate and make it more challenging to lose weight. Other examples of medical conditions that may lead to weight gain and inhibit coffee-induced weight loss include: chronic fatigue syndrome, depression, hepatic impairment, renal dysfunction, etc. Other medical conditions are associated with weight loss and may accelerate coffee-induced weight reduction. Examples of such conditions may include: bowel disorders, cancer, depression, gastroenteritis, hyperthyroidism, infections (e.g. HIV), etc. When determining if you are likely to lose weight from coffee intake, medical conditions should be assessed. Moreover, many medical conditions (and medications used to treat them) can affect how a person’s physiology responds to coffee constituents such as caffeine and may influence whether someone is likely to lose weight.
- Sex: There may be sex-specific responses to coffee constituents that might influence likelihood of weight loss from its consumption. In other words, it’s possible that men (on average) experience more/less significant weight loss from coffee consumption than women. Differences in physiologic reactions to coffee may be contingent upon sex-specific hormone levels and/or body composition. For example, men produce more testosterone and tend to have less body fat than women, each of which might influence how coffee interacts with physiology to facilitate weight reduction. It’s also possible that sex-specific physiologic differences have zero significant influence on whether someone is likely to lose weight from drinking coffee. However, research by Temple and Ziegler (2011) indicates that males and females differ in responses to caffeine and that these responses might be contingent upon sex-specific concentrations of steroid hormones. Although it remains unclear as to whether sex-specific responses to caffeine would lead to greater weight loss in one sex versus another, it’s a possibility that necessitates mentioning. (Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3621315/).
- Sleep: The quantity and quality of a person’s sleep may also influence whether they are likely to lose weight from drinking coffee. According to a study by Thomson, Morrow, Flatt, et al. (2012), individuals who sleep at least 7 hours per night and subjectively perceive their sleep to be of good quality – tend to lose more weight than persons who sleep fewer than 7 hours per night and/or perceive their sleep to be of poor quality. Furthermore, research by Nedeltcheva, Kilkus, Imperial, et al. (2010) discovered that insufficient sleep interferes with preexisting dietary-mediated efforts to reduce adiposity. Considering these findings, it’s reasonable to suspect that individuals who optimize sleep [in terms of quantity and quality] will be more likely to lose weight from the consumption of coffee. (Source #1: https://www.ncbi.nlm.nih.gov/pubmed/22402738, Source #2: https://www.ncbi.nlm.nih.gov/pubmed/20921542).
- Stress: Another factor that may play influence whether you lose weight from drinking coffee is your stress level. It is known that chronic stress can significantly alter aspects of physiology including: epigenetic expression, neurotransmission, and hormone secretion. Ongoing stress can also disrupt a person’s circadian rhythm and/or impair sleep quantity/quality – each of which is associated with weight gain. On the other hand, stress can sometimes blunt the appetite and/or increase resting metabolic rate to facilitate weight loss. A person who loses weight from stress may find that coffee amplifies weight loss, whereas a person who gains weight from stress may find that coffee inhibits some of the stress-induced weight gain. That said, most evidence indicates that chronic stress is associated with increased adiposity and weight gain – not weight loss. For example, a large-scale correlational study by Harding, Backholer, Williams, et al. (2014) discovered that psychosocial stress was positively associated with weight gain – but not weight loss. Some believe that stress generally increases appetite for hyperpalatable (high-fat/high-sugar) foods and reinforces neurocircuitry implicated in food cravings and addiction. For this reason, it should be suspected that if you have high stress, you’ll be less likely to lose weight from drinking coffee. If you keep your stress level low and/or experience intermittent bouts of mild-to-moderate stress, coffee will have a greater chance of facilitating weight loss. (Source: https://www.ncbi.nlm.nih.gov/pubmed/23512679).
Drinking Coffee & Weight Loss: Review of Research
To determine whether drinking coffee may effectively promote and/or induce weight loss, it is necessary to examine the available data from research in which the effect of coffee on body weight has been investigated. Upon analysis of the literature, it seems as though there are epidemiological studies in which associations were formed between coffee intake and body weight, however, our confidence in the reliability of data from these studies is low. Low confidence in the reliability of findings of epidemiological studies is due to the fact that these studies: lack randomization and controlling, generally rely upon participant self-reporting (which is often inaccurate), and often fail to adjust for all potential confounds. That said, nearly all of the available research supports the idea that coffee consumption can promote modest weight loss and/or prevent weight gain – over the short-term and long-term.
2016: Caffeine intake is related to successful weight loss maintenance.
Icken, Feller, Engeli, et al. (2016) reported that the effect of caffeine intake on weight loss maintenance of humans was never investigated among humans. For this reason, researchers conducted a study in which daily consumption of coffee and other caffeinated beverages were compared between 494 persons who successfully maintained body weight following weight loss and 2,129 individuals from the general population. It was noted that researchers controlled for potential confounds such as sociodemographic influences, BMI (body mass index), and average physical activity level.
Results of the study indicated that the 494 successful weight loss maintainers consumed significantly more cups of coffee and other caffeinated beverages than participants in the general population. The conclusion from this investigation was that consumption of caffeinated beverages might support weight loss maintenance. It was noted that further research is needed to substantiate these findings and elucidate the mechanisms by which this effect may occur.
Despite these findings, there are some potentially significant limitations of this study worthy of discussion. One limitation is that we don’t know the cumulative duration over which individuals had consumed caffeine nor whether they had developed tolerance. Perhaps many of the individuals who’ve maintained their weight loss over an extended duration became tolerant to the weight loss effect of caffeine, and in order to maintain their weight loss, they further ramped up caffeine intake.
The further increased caffeine intake may have prevented tolerance to caffeine while simultaneously enhanced neurophysiological effects of caffeine that are conducive to weight loss, thereby playing a role in successful weight loss maintenance. That said, it’s possible that over a longer duration, these individuals would reach a peak daily caffeine dosage to which they’d become tolerant. Once tolerance is established to a peak daily caffeine dosage, the weight loss may become more difficult to maintain.
Another limitation of the study is that there may have been genetic or epigenetic confounds for which researchers couldn’t have controlled. These genetic or epigenetic substrates may have better explained successful weight loss maintenance in the 494 individuals. Behaviors such as calorie tracking coupled with dietary factors such as average daily caloric intake and types of calories consumed – may have affected the results.
Moreover, evidence from other research suggests that weight loss maintenance might get easier over time. Once a person has successfully maintained weight loss for an extended duration (e.g. 2 to 5 years), the chance of long-term success significantly increases. Perhaps this is explained by some sort of psychological desire to maintain positive momentum or neurochemistry and corresponding mood; weight loss is generally associated with mood improvements.
Overall, the findings of this study reveal a positive relationship between coffee and/or caffeinated beverage intake and successful weight loss maintenance. However, the findings do not suggest that coffee and/or caffeinated beverage intake definitively plays a role in weight loss maintenance.
- Source: https://www.ncbi.nlm.nih.gov/pubmed/26554757
2014: Effect of chronic coffee consumption on weight gain and glycaemia in a mouse model of obesity and type 2 diabetes.
Data from epidemiological studies indicate that chronic coffee consumption in humans may reduce risk of type 2 diabetes. To understand the mechanisms by which coffee may reduce type 2 diabetes risk, researchers Rustenbeck, Lier-Glaubitz, Willenborg, et al. (2014) organized a study using animal models of diabetes. For the study, male C57BL/6 mice were divided into groups and assigned to receive either: a high-fat diet (55% fat) or a normal diet (9% lipids).
All mice, regardless of dietary assignment, received coffee and water ad libitum. The mice receiving the high-fat diet (55% lipids) developed obesity and diabetes within 10 weeks and maintained this adverse health status for 35 additional weeks. In comparison, mice who received a normal diet (9% lipids) did not develop obesity nor diabetes throughout the duration of the study.
Results of the study indicated that coffee consumption dose-dependently negated weight gain in mice receiving the high-fat diet, and completely eradicated weight gain in mice receiving the normal diet. Interestingly, mice who received the high-fat diet consumed significantly fewer total fluids (coffee and water) throughout the study than mice who received normal diets, meaning the latter group of mice had greater exposure to coffee. During Week 21 of the study, intraperitoneal glucose tolerance tests (IPGTTs) indicated a significantly quicker reduction in elevated glucose concentrations among coffee-consuming high-fat diet recipients, but not among normal diet recipients.
Moreover, there was a marked reduction in non-fasting blood sugar concentrations after Week 21 in all mice regardless of diet. By Week 39 of the study, IPGTT records indicated reduced peak glucose concentrations in coffee-consuming high-fat diet mice. The results of the study indicate that coffee intake attenuates weight gain and enhances glucose tolerance in animal models of type 2 diabetes.
That said, only a specific strain (C57BL/6) of male mice were utilized in this study, meaning that the results may not generalize to other strains and/or female mice. It also should be questioned as to whether the mice in this study ever developed neurophysiological tolerance to the constituents within coffee responsible for weight modulation. If tolerance to these coffee constituents (e.g. caffeine) never developed, possibly due to ad libitum allowance and/or the limited duration of the study, perhaps this explains the weight loss.
Had the study been conducted over double or triple the timespan with fixed-doses of coffee for the mice, it’s possible that the observed weight loss in mice have diminished or ceased altogether. Moreover, while the results of this animal study cannot be extrapolated to humans, based on these findings, it’s reasonable to hypothesize that coffee consumption induces weight loss in humans. In other words, coffee may dose-dependently minimize weight gain among consumers of unhealthy and/or caloric surplus diets, and completely inhibit weight gain among consumers of healthy and/or calorically-normative diets. It’s also possible that coffee may augment weight loss in consumers of calorically-restricted diets.
- Source: https://www.ncbi.nlm.nih.gov/pubmed/24979152
2013: Effect of different amounts of coffee on dietary intake and appetite of normal-weight and overweight/obese individuals.
Gavrieli, Karfopoulou, Kardatou, et al. (2013) sought to determine the effect of coffee intake on the appetite feelings of normative-weight and overweight/obese persons. For this reason, a study was organized in which 16 normative-weight and 17 overweight/obese individuals participated. The study assigned 33 participants to receive the following [with a standard breakfast] on three separate occasions: 200 ml coffee (3 mg caffeine per kg of body weight); 200 ml coffee (3 mg caffeine per kg of body weight); or 200 ml water.
Within a 3-hour window following each breakfast, participants documented their appetite feelings via a visual analogue scale. Upon completion of the 3-hour post-breakfast windows, participants received an ad libitum meal. The day after each of the trials, participants were instructed to recall their total food intake from the previous experimental day.
Data indicated that, among obese/overweight participants, coffee consumption influenced caloric intake in the ad libitum meal, as well as caloric intake throughout the entire day. In particular, receiving coffee containing 6 mg caffeine per kg of body weight resulted in significantly reduced caloric intake in the ad libitum meal, as well as throughout the rest of the day, whereas receiving coffee containing 3 mg caffeine per kg of body weight OR water (control) – had no effect on caloric intakes. It was also discovered that coffee consumption had no significant effect on appetite feelings as measured by the visual analogue scale.
Researchers concluded that, for obese/overweight individuals, moderate coffee consumption with breakfast can inhibit caloric intake in a subsequent meal, as well as caloric intake throughout the entire day. Comparatively, modest or zero coffee consumption with breakfast had no effect on caloric intake of a subsequent meal or caloric intake throughout the entire day. These results support the idea that moderate coffee consumption could promote weight loss among obese/overweight individuals through reducing caloric intakes.
That said, there are many limitations associated with this study including the small sample size, trial duration, caffeine dosage administered, and the laboratory setting. With a sample of just 33 participants, 17 of which were obese/overweight, it’s possible that the observed significant outcome of lower caloric intake was due to random chance. Moreover, since the psychostimulant constituents of coffee likely explain the caloric restriction observed after moderate doses, it’s possible that a longer-term study may have found no significant effect after onset of caffeine tolerance.
Assuming someone receives the same coffee with 6 mg caffeine per kg body weight at each breakfast, it may be a matter of time before the observed effect of caloric restriction plateaus and abates. Additionally, we must consider that the significance of caffeine’s neurophysiologic impact may not be entirely dictated by a person’s current body weight. It’s possible that similar doses of caffeine yield relatively similar effects in most people irrespective of body weight.
Someone at a normative weight of 150 lbs. would’ve received 408.23 mg of caffeine in the moderate strength coffee, whereas someone with obesity at 300 lbs. would’ve received 816.47 mg of caffeine in the moderate strength coffee. Although double the body weight may require an increased dosage of caffeine for a neurophysiological effect, the dosage needed to generate the same effect in a 300 lb. person may not be double that of a 150 lb. person. Thus, we must speculate that perhaps the larger individuals would’ve received a large caffeine dose with substantially greater potency compared to the others, ultimately yielding greater psychostimulation to explain the lower caloric intake.
- Source: https://www.ncbi.nlm.nih.gov/pubmed/23671022
2011: Dark roast coffee is more effective than light roast coffee in reducing body weight, and in restoring red blood cell vitamin E and glutathione concentrations in healthy volunteers.
Kotyczka, Boettler, Lang, et al. (2011) discussed findings from prospective cohort studies in which moderate coffee intake was linked to lower risk of diabetes (type 2) and Alzheimer’s disease. Because reactive oxygen species (ROS) are implicated the pathogenesis of both diabetes (type 2) and Alzheimer’s disease, if coffee consumption actually reduces risk of the aforementioned diseases, researchers hypothesized that its antioxidant constituents might play a role in the risk reduction. Due to earlier research suggesting that the antioxidant status of coffee is subject to variation based upon the type of roast, researchers sought to compare the antioxidant effect of dark roast coffee to that of light roast coffee.
Researchers organized a randomized 12-week longitudinal trial in which 30 healthy volunteers participated. The volunteers were instructed to follow a diet low in polyphenols and received a controlled 4-week intake of 500 ml light roast coffee (low in N-methylpyridinium ions and high in chlorogenic acids). Next, participants entered a 2-week washout phase in which they received no coffee and were instructed to avoid polyphenols.
Upon completion of the washout phase, participants received a controlled 4-week intake of 500 ml dark roast coffee (high in N-methylpyridinium ions and low in chlorogenic acids). It was noted that both the light roast coffee and dark roast coffee were of the same bean variety. To determine the antioxidant effect of each specific type of roast, blood and urine samples were collected from participants at baseline and endpoint of each administration term.
Results indicated that dark roast coffee significantly enhanced antioxidant status of erythrocytes (red blood cells) compared to light roast coffee. Specifically, the dark roast coffee increased concentrations of tocopherol (41%) and glutathione (14%) and decreased concentrations of superoxide dismutase (-5.8%) and glutathione peroxidase (-15%). Moreover, the dark roast significantly decreased body weight of pre-obese participants by an average of 5.5 lbs., whereas the light roast coffee had no effect on body weight.
The high concentration of N-methylpyridinium ions within dark roast coffee may explain the significant antioxidant effect, as well as weight loss induction among pre-obese recipients. That said, there are some limitations associated with this study including: the small sample size (30 participants), the order of administration (light then dark roast), and the duration of the washout phase (2 weeks). Perhaps with a larger sample size, with a different order of administration (e.g. dark then light), and a longer washout phase (e.g. 1-month), results may have differed. Nevertheless, this study supports the idea that short-term dark roast coffee may induce weight loss in overweight persons.
- Source: https://www.ncbi.nlm.nih.gov/pubmed/21809439
2006: Coffee, diabetes, and weight control.
A review by Greenberg, Boozer, and Geliebter (2006) highlighted links between coffee consumption, diabetes risk, and body weight. Authors noted that, according to results of epidemiological studies, coffee consumption (both caffeinated and decaffeinated) is linked with a lower diabetes risk. However, data from human trials in which coffee consumption was found to decrease glucose tolerance are indicative of the possibility that coffee consumption might actually increase diabetes risk.
In their review, authors believe that the effect of coffee consumption on diabetes risk may be mediated by changes in body weight. The results of an epidemiological study referenced in the review suggested that coffee consumption decreased diabetes risk, but only among participants who lost weight. Another epidemiological study was discussed in which caffeine and coffee intake had a modest inverse correlation with weight gain.
Authors suggested that various coffee constituents such as caffeine, chlorogenic acid, and quinides – may directly induce weight loss. This review supports the hypothesis that coffee consumption can cause modest weight loss. That said, it should be emphasized that this review assessed data from epidemiological studies and focused specifically on diabetic populations.
We must consider that individuals with diabetes might exhibit different responses to coffee consumption in terms of its effect on body weight – compared to non-diabetic persons. Furthermore, since epidemiological studies are not subject to randomization nor controlling and generally struggle to account for a myriad of potential confounds that may affect results, the quality of data they generate is low. Nonetheless, there appears to be a link between coffee consumption, weight loss,
- Source: https://www.ncbi.nlm.nih.gov/pubmed/17023692
2006: Changes in caffeine intake and long-term weight change in men and women.
Lopez-Garcia, van Dam, Rajpathak, et al. (2006) sought to determine the effect of caffeine intake on body weight over a long-term. To accomplish this, researchers organized a prospective study that monitored caffeine intake and weight change among 18,417 males and 39,740 females over a 12-year period [from 1986 to 1998]. Upon commencement of the study, it was noted that none of the participants had been diagnosed with chronic medical diseases.
Throughout the study, the caffeine intake and body weight of each participant was recorded every 2 to 4 years. The long-term effect of caffeine intake on body weight was determined based upon change in self-reported body weight from baseline (1986) to endpoint (1998) in relation to caffeine intake. After the 12-year study period, age-adjusted data revealed that increased caffeine consumption was associated with lower average weight gain in both males (-0.95 lbs.) and females (-0.90 lbs.) – than decreased caffeine consumption.
Following adjustments for additional confounds (e.g. total caloric intake, food choices, nutrients, etc.), the differences in average weight gain [in relation to increased caffeine consumption] remained the same for males (-0.95 lbs.), yet decreased slightly for females (-0.77 lbs.). The researchers discovered a relationship between increased coffee and tea consumption and lower long-term weight gain. Among males, caffeine intake had a substantially stronger effect on body weight in younger participants compared to older participants.
Among females, caffeine intake had a stronger effect on body weight in participants with a BMI of 25 kg/m2 or greater, who were physically active, and/or smokers. The conclusion from this prospective study was that increased caffeine intake may modestly inhibit long-term weight gain. Relevant to this article is the specific finding that coffee consumption was associated with lower long-term weight gain in the cohort.
Still, it is possible that individuals who regularly drink coffee are of higher socioeconomic status whereby they can afford to spend more on coffee to consume. It’s also possible that numerous other unconsidered confounding factors would’ve explained the correlation between coffee intake and lower long-term weight gain. Perhaps coffee drinkers are, on average, more health-conscious than others – preferring coffee over unhealthier beverages (e.g. sodas).
Moreover, the most significant limitation of this study is that it relies upon participants’ self-reporting of caffeine intake and body weight for data. Not only might body weight measures be inaccurate, but having participants estimate caffeine intake and regularity of intake may yield grossly unreliable data. That said, while this study does not prove that caffeine intake induces weight loss, the findings support such a possibility.
- Source: https://www.ncbi.nlm.nih.gov/pubmed/16522916
2005: Coffee, tea and diabetes: the role of weight loss and caffeine.
Greenberg, Axen, Schnoll, and Boozer (2005) investigated the impact of weight change on the link between coffee and/or tea consumption and diabetes risk. Researchers conducted a study in which they gathered baseline data from participants in the first National Health and Nutrition Examination Survey (NHANES), as well as from the very first follow-up survey. A total of 7,006 individuals (ages 32 to 88) with no prior history of diabetes at baseline – met criteria to be included in the data analysis.
Additional follow-up surveys were then used to document onset of diabetes, changes in body weight plus BMI, and caffeine intake. Data from the follow-up surveys indicated that greater intakes of ground coffee and caffeine at baseline were associated with lower diabetes risk. That said, age-grouped assessments indicated that lower diabetes risk was only observed among individuals under 60 with greater intakes of ground coffee and caffeine.
What’s more, the reduction in diabetes risk appeared to be dose-dependent such that the greater the amount of coffee consumed, the more substantial the reduction in diabetes risk. However, further analysis of the data indicated that ground coffee and/or caffeine only reduced diabetes risk [among persons under 60] if they had previously lost weight. A dose-dependent relationship between weight loss and diabetes risk was documented, such that, the greater a person’s weight loss, the lower his/her diabetes risk.
Based on this finding, it is reasonable to speculate that weight loss itself may have been the chief reason as to why individuals exhibited lower diabetes risk [rather than coffee and/or caffeine intake]. Furthermore, researchers underscored the finding that there was no link between diabetes risk and intake of instant-caffeine coffee, instant-decaffeinated coffee, or herbal tea. Nonetheless, it appeared as though ground coffee and regular tea were associated with both reduced diabetes risk and weight loss in younger populations. The fact that ground coffee was associated with weight loss supports the idea that drinking coffee may promote weight loss.
- Source: https://www.ncbi.nlm.nih.gov/pubmed/15925959
1980: Caffeine and coffee: their influence on metabolic rate and substrate utilization in normal weight and obese individuals.
In attempt to elucidate the effect of caffeine and coffee on metabolic rate and substrate utilization in humans, researchers Acheson, Zahorska-Markiewicz, Pittet, et al. (1980) conducted a series of experiments. The first experiment involved comparing the effect of caffeine (8 mg/kg) to that of a placebo in a sample of normal weight individuals. For a 3-hour period after caffeine or placebo administration, metabolic rate and substrate utilization were assessed.
Results of the first experiment revealed that caffeine ingestion significantly increased metabolic rate [within the 3-hour post-ingestion assessment period]. Additionally, caffeine ingestion markedly increased fat oxidation and plasma free fatty acid concentrations (from ~432 muEq/liter to ~848 muEq/liter). The second and third experiments involved comparing the specific effect of coffee [containing 4 mg/kg caffeine] in normal weight versus obese individuals.
Results of the second and third experiments revealed that coffee [with 4 mg/kg caffeine] significantly increased metabolic rate in all persons – regardless of weight. That said, significant increases in fat oxidation were only observed among persons of normative body weight. In a fourth experiment, participants received coffee with a meal (~736.14 calories).
Results of the fourth experiment revealed that standard [caffeinated] coffee significantly increased the thermic effect of the meal and fat oxidation. For reference, the thermic effect of food (TEF) refers to the expenditure of energy above resting metabolic rate due to processing food for usage and storage. The significant increases in thermic effect of food and fat oxidation were not observed after consumption of decaffeinated coffee.
In summary, this series of experiments suggests that caffeine and coffee increase metabolic rate of humans irrespective of body weight. Furthermore, persons of normal weight exhibit increases in fat oxidation after caffeine/coffee consumption. The aforestated findings support the concept that coffee consumption might help regulate body weight through modulation of metabolic rate, and in some cases, fat oxidation.
- Source: https://www.ncbi.nlm.nih.gov/pubmed/7369170
Note: Since this article is focused entirely on the relationship between drinking coffee and weight change, preexisting research of specific coffee-related extracts (e.g. green coffee bean extract) were omitted from discussion.
Does drinking coffee cause weight loss?
Since no randomized controlled trials (RCTs) with large-sample sizes have been conducted over a long-term to assess whether coffee intake affects body weight, it remains unclear as to whether drinking coffee causes weight loss. That said, it is necessary to highlight the fact that nearly all currently-available literature supports associations between coffee consumption and weight loss and/or prevention of weight gain. For example, a 12-year correlational study by Lopez-Garcia, van Dam, Rajpathak, et al. (2006) among 58,157 persons discovered that caffeine consumption was positively associated with lower weight gain in both younger males and females by approximately -0.95 lbs. and -0.77 lbs., respectively.
The conclusion of the aforestated study was that increased caffeine intake may modestly inhibit long-term weight gain. Most would consider weight loss of -0.95 lbs. and -0.77 lbs. over a 12-year span to be extremely negligible, however, persons who didn’t consume caffeine appeared to gain weight. Assuming a person drinks caffeinated coffee (as opposed to decaffeinated), it may be easier to lose a bit of weight and/or minimize weight gain due to the caffeine contents.
More evidence that coffee could facilitate weight loss is derived from a paper by Greenberg, Boozer, and Geliebter (2006) in which coffee intake was mentioned as being inversely associated with weight gain. The authors hypothesized that compounds within coffee such as caffeine, chlorogenic acid, and quinides could prevent weight gain or induce weight loss. Additional support for the idea that coffee could induce weight loss is derived from a study by Kotyczka, Boettler, Lang, et al. (2011).
The aforestated study reported weight loss of approximately 5.5 lbs. in pre-obese participants after consumption of dark roast coffee for a 12-week duration. What’s more, an experiment by Gavrieli, Karfopoulou, Kardatou, et al. (2013) noted that coffee with caffeine (6 mg per kg body weight) significantly reduced caloric intake in overweight/obese persons. Hypothetically, if this effect is accurate and consistent over a long-term, it may yield a negative energy balance for weight loss.
Research by Rustenbeck, Lier-Glaubitz, Willenborg, et al. (2014) discovered that consumption of coffee by mice with a genetic predisposition to metabolic syndrome leads to dose-dependent attenuation of weight gain on a high-fat diet, a finding that further supports the ability of coffee to induce weight loss. More recently, research by Icken, Feller, Engeli, et al. (2016) showcased that fact that individuals who lose weight and successfully maintain the weight loss tend to consume more coffee than others, indicating that coffee may prevent weight gain. Everything considered, the cumulative body of literature implies that consumption of unaltered (zero-additive) coffee is linked to weight reduction rather than weight gain.
Although correlation between coffee consumption and weight loss cannot be assumed as causation, a causal relationship is possible. After all, there are no data indicating that coffee is likely to induce weight gain and/or interfere with preexisting weight loss efforts. Moreover, there are many mechanisms by which coffee could [theoretically] generate a weight loss effect including: antioxidant contents, appetite suppression, autonomic nervous system (ANS) modulation, inflammation reduction, et al.
Limitations associated with research of coffee for weight loss
While most research supports links between coffee and weight loss and/or inhibition of weight gain, there are some serious limitations associated with the research that warrant discussion. Arguably the most substantial limitation is that zero randomized controlled trials have been conducted in attempt to determine whether coffee is causally implicated in weight loss induction and/or inhibition of weight gain. Without randomized controlled trials (preferably over a long-term with a large sample size), we cannot know whether drinking coffee legitimately causes weight loss – or if there’s merely a correlation.
Other limitations associated with the research include heterogeneity in things like: coffee specifics, administration details, and sample demographics. Below is a list and brief description of limitations associated with the research of coffee for weight loss. Understand that until the aforestated limitations are properly addressed, it’ll be difficult to definitively know whether coffee is likely to cause weight loss.
- Administration details: It is possible that the specific details of coffee administration influence whether it is likely to induce weight loss. Administration details include things like: time of day consumed, rate of consumption, temperature, and whether consumed on an empty stomach vs. with food. Perhaps consuming hot coffee in the morning at a slow rate (e.g. sipping) on an empty stomach is more conducive to weight loss than consuming iced coffee in the evening at a fast rate (e.g. chugging) on a full stomach. Unless the specific details of administration are standardized across research, it’s possible that differences may be culpable for generating entirely different results.
- Coffee details: Since there are many variations of coffee on the market, it’s possible that one specific type of coffee causes weight loss and another does not. It’s also possible that many types of coffee induce weight loss, but the weight loss with one type is more substantial than that induced by another. In fact, preliminary evidence from research by Kotyczka, Boettler, Lang, et al. (2011) supports the idea that coffee details may matter in terms of their effect on body weight. Kotyczka, Boettler, Lang, et al. discovered that only “dark roast” coffee induced weight loss in pre-obese participants – but “light roast” did not. If attempting to determine whether coffee is likely to cause weight loss, it is important to recognize that Arabica, Robusta, and Liberian formats may differ in the facilitation of weight loss due to variation in constituents (e.g. antioxidants, caffeine, mycotoxins, etc.). Furthermore, even if only one type of coffee bean (e.g. Arabica) is used in research, Arabica beans from one source used in a study may differ slightly from those used in another study, perhaps enough to yield different research outcomes. Therefore, researchers should endeavor to utilize standardized, ultra-pure coffee beans of one specific type (e.g. Arabica) from one specific source, and preparation should be the exact same (preferably done by a machine).
- Decaffeinated (?): One study by Geliebter (2012) reported that decaffeinated coffee significantly reduced hunger for 90 minutes post-consumption as compared to a placebo and caffeinated coffee. Interestingly, the decrease in hunger post-decaffeinated coffee consumption was associated with elevations in peptide YY (PYY), an anorectic hormone involved in appetite suppression. Although coffee is not inherently decaffeinated, some individuals consume decaffeinated variants. For this reason, it would be useful to investigate whether there are significant differences between standard caffeinated coffee and decaffeinated coffee in terms of inducing weight loss. This research would help determine whether caffeine is involved in the generation of a weight loss effect.
- Dosing: Another potentially serious limitation is that most trials administer a fixed amount of coffee to participants, but modify the amount of caffeine within the coffee based on participants’ body weights. In other words, all participants end up receiving 1 cup of coffee, but the caffeine content will be 4 mg, 6 mg, or 8 mg per kilogram of the participant’s body weight. Assuming the study is using an 8 mg/kg caffeine dose, a 100-lb. person would receive 362.87 mg caffeine, a 200-lb. person would receive 725.75 mg caffeine, and 400-lb. person would receive 1451.5 mg caffeine – in their respective cups of coffee. Although it is known that larger individuals can tolerate more caffeine than smaller persons, adjusting caffeine content based on weight may be problematic. Firstly, we must consider that body composition in terms of fat percentage and muscle mass may influence how a person responds to coffee terms of weight reduction. Someone who weighs 200 lbs. at 8% body fat may respond differently to the 725.75 mg caffeine than a person who weighs 200 lbs. at 30% body fat. It is also necessary to consider that there may be a threshold at which weight-based dosage increases in caffeine content are no longer of equivalent physiologic potency. In fact, it may be favorable for participants to receive a fixed-dose of coffee and caffeine irrespective of body weight (e.g. 300 mg for every participant). When caffeine content is adjusted simply based on weight, a 400 lb. person likely ends up with significantly more caffeine acting upon his/her central nervous system than a 200 lb. person. Moreover, genetic variants in CYP1A2, ADORA2A, and COMT may be useful to investigate as each pertains to the physiologic effect of a particular dose of caffeine.
- Incentives: There’s not really any incentive to find out whether coffee may affect body weight. It is estimated that upwards of 80% of adults in the United States drink coffee regularly and few want to cut back on their consumption. If coffee turned out to help with weight loss, it’s unlikely that significantly more people would start drinking it. Furthermore, since coffee cannot be patented, no single company stands to gain financially if they invest in research to prove that coffee induces weight loss. Even researchers have nothing to gain from investing time and research dollars to determine whether coffee causes weight loss. Most researchers would be better suited testing novel weight loss interventions that have a chance at making a bigger impact on weight.
- Sample sizes: Many epidemiological studies with large sample sizes have reported links between coffee consumption and weight loss and/or prevention of weight gain. In epidemiological studies, it is extremely important to implement large sample sizes because it already lacks randomization and controlling. Larger samples provide a more accurate representation of coffee’s effect within the general population, rather than just 10 or 20 people. A study with just 20 people may conclude that coffee consumption caused weight loss, yet because the sample is so small, the finding may have been nothing more than random chance. Epidemiological studies aside, it would be useful to conduct a randomized controlled trial with a large sample size analyzing whether coffee facilitates significant weight loss. Thus far, the single study that incorporated randomization into its design only recruited 30 participants. Though a sample with 30 participants is better than 10 participants, it is not a large enough sample to generate trustworthy data.
- Sample specifics: It is known that the specific sample utilized in a study can affect its results. The research of coffee’s effect upon body weight is no different. When researchers fail to account for specific details such as: average BMI, body composition (fat and muscle mass), genetic variants that influence the effects of caffeine (e.g. CYP1A2, ADORA2A, COMT, etc.), and regularity of coffee intake (prior to the study) – results may be subject to significant variation between studies. Obviously recruiting an extremely large, heterogeneous sample could help researchers determine whether a particular subset of the sample (e.g. persons with multiple CYP1A2*1A alleles) loses more weight from coffee consumption than others. That said, since it is difficult to recruit a large sample size, it may be best to assess the effects of coffee on body weight in one specific sample (e.g. coffee-naïve obese/overweight persons) rather than a small mixed sample.
- Study designs: As was mentioned, in order really to know whether coffee causes weight loss randomized controlled trials are needed. To present data, no randomized controlled trials have tested whether coffee may induce weight change. Most of the current research assessing the effect of coffee on body weight is derived from epidemiological studies. Epidemiological studies do not incorporate any randomization nor controlling and are notoriously unreliable.
- Trial duration: While epidemiological studies have been conducted to determine whether coffee might induce weight loss when consumed over an extended duration (e.g. 12-years), the quality of data from epidemiological studies is low. For this reason, randomized controlled designs should be conducted over a long-term. A long-term trial allows researchers to observe coffee-induced weight loss over a short-term (e.g. 0 to 6 months) and monitor participants for possible regaining of weight after tolerance development (e.g. 6 months to 1 year).
Coffee & Weight Loss: Frequently Asked Questions (FAQs)
Included below are some frequently asked questions regarding the relationship between coffee and weight change. Most people want to know how much coffee they should be drinking to lose weight, the best type of coffee for weight loss, and how much weight a person can lose from drinking coffee. Others may want to know whether it’s possible that coffee could cause weight gain. Because there are no randomized controlled trials that’ve assessed the effect of coffee on body weight, the answers to these frequently asked questions are inconclusive. Moreover, if you have any questions regarding the effect of coffee on your body weight or the safety of coffee consumption, speak with a medical doctor.
How much coffee should you drink to lose weight?
As has been already stated, there’s no convincing evidence that drinking coffee induces weight loss. Nonetheless, if coffee legitimately facilitates a weight loss effect, the available research highlights a dose-dependent relationship between coffee/caffeine and weight loss in humans and animal models. In other words, the more coffee/caffeine consumed, the greater the likelihood of weight loss and/or inhibition of weight gain.
Before anyone starts chugging coffee by the gallon, on the speculation that it may induce weight loss, it is important to be cognizant of toxicity at high doses. Furthermore, it is important to confirm that coffee is safe to drink in accordance with your medical status, gene expression (CYP1A2, COMT, etc.) and regimen of medications and/or supplements. Also realize that side effects tend to increase at higher doses, and many of these side effects (e.g. anxiety, jitters, restlessness) may not outweigh the weight loss.
What’s the best type of coffee to drink for weight loss?
Thus far there’s more evidence to support the idea that standard coffee facilitates weight loss in accordance with caffeine content. In other words, the greater the caffeine within your coffee, the more likely weight loss is to result from its consumption. That said, one study comparing decaffeinated preparations to standard coffee (with caffeine) found that the decaffeinated coffee suppressed appetite significantly more than standard coffee.
The appetite suppression from decaffeinated coffee was linked to increases in peptide YY (PYY). While one study found that decaffeinated coffee suppressed appetite more than standard coffee, this study was of extremely short-duration with a small sample size. Moreover, larger studies support the idea that caffeine may play a role in weight loss – making standard coffee the more appealing choice for most.
No specific “brand” recommendations can be made because none were documented in the literature. There was one study that compared 2 different roasts from the same company and discovered that the “dark roast” outperformed the “light roast” in upregulating antioxidant status. In addition, the “dark roast” also induced significant weight loss (~5.5 lbs.) in pre-obese participants when consumed daily for a 1-month duration.
All findings considered, it would be most logical to consume some caffeinated coffee, preferably of a dark roast, if one is hoping to lose weight from coffee intake. Furthermore, it may be helpful to consume some decaffeinated coffee after consumption of caffeinated coffee (e.g. before dinner). If there are appetite suppressant effects that can only be derived from decaffeinated coffee, consumption prior to a meal should help individuals restrict calories.
How much weight will you lose from drinking coffee?
Under the assumption that coffee can induce weight loss, there’s no telling how much each specific person will stand to lose from its consumption. The amount of weight you lose may be contingent upon many factors including the type/dosage of coffee consumed and the consumer’s: age, genetics, preexisting weight loss efforts, medical conditions, medications used, etc. In an epidemiological study conducted over a 12-year period, coffee drinkers reportedly weighed between 0.7 and 1 lb. less than non-coffee drinkers.
Therefore, the amount of weight most people lose from coffee consumption may be negligible or modest. Extreme weight loss solely attributable to coffee should not be expected. One study reported weight loss of 5.5 lbs. when coffee was consumed over a 1-month duration, but this only applied to pre-obese persons – not individuals exhibiting normative body weights. Still, it’s unclear as to whether individuals may have gained some of this weight back over a longer-term.
How long will it take to lose weight from drinking coffee?
If coffee causes you to lose weight, the weight loss probably won’t be very noticeable for at least a few weeks. Some research has reported weight loss from coffee consumption as occurring within 1 month. The speed at which a person loses weight from his/her coffee consumption will likely be individualized based on factors such as complementary weight loss efforts (e.g. caloric restriction, exercise, etc.), amount of coffee consumed, type of coffee consumed, etc. In other words, two people may drink the same amount and type of coffee, yet one may experience quicker weight loss than another – even if both end up losing weight.
Could some people gain weight from drinking coffee?
There are no data, even from correlational studies, suggestive of the possibility that coffee might cause weight gain. That said, it’s possible that some individuals lose weight from coffee and end up gaining it back as they develop tolerance. Another possibility is that individuals might lose weight drinking one type of coffee, and when they switch to another, they gain weight.
For example, switching from a dark roast coffee with a low mycotoxin count to a light roast coffee with a high mycotoxin count may lead to weight gain attributable to fewer antioxidants and/or more mold. Furthermore, consuming hot coffee in plastic cups may lead to weight gain from the endocrine disruption of the plasticizers (e.g. BPA). Lastly, adding ingredients to your coffee that contain calories (e.g. cream) and/or affect hormones (e.g. sugar) will add to your daily caloric load and could yield weight gain.
If coffee interferes with your sleep, increases your stress level, and/or leads you to eat more throughout the day – you may also gain weight from its consumption. Realize that not everyone will lose weight from their coffee intake – some could gain weight, and others might remain relatively weight neutral.
Have you lost weight from drinking coffee?
If you’ve lost weight from drinking coffee, feel free to share your experience in the comments section below. To help others understand your situation, mention the amount of weight you lost after you started drinking coffee, and provide some details associated with your coffee consumption such as: the amount consumed daily (e.g. 3 cups per day), the type of coffee you drink, and when you drink it (e.g. morning-only before working out and/or breakfast). Assuming you find coffee to be useful for the induction of weight loss, in what ways do you consider it most helpful?
Potential answers might include: as a meal replacement, appetite suppressant, energy booster [for workouts], burning fat, etc. For those who’ve consumed coffee over a long-term (e.g. years), did you find that initial weight loss from short/moderate-term coffee consumption was eventually regained [perhaps due to tolerance]? Or did you notice that the weight you initially lost stayed off and that coffee now helps you maintain your body weight by inhibiting weight gain?