Caffeine and Weight Loss
Caffeine is a stimulant that can make you more alert, give you a boost of energy, burn calories, and increase the breakdown of fat. Often added to weight-loss dietary supplements, caffeine is found naturally in tea, guarana, kola nut, yerba mate, and other herbs. The labels of supplements that contain caffeine don’t always list it, so you might not know if a supplement has caffeine.
Caffeine 1), 2), 3), 4) has been shown to increase energy expenditure in humans, and weight loss has reduced risk factors for diabetes in clinical trials 5). Consequently, it seems possible that both coffee and tea consumption may decrease diabetes risk by helping individuals control their body weight.
Caffeine may also slightly boost weight loss or prevent weight gain, but there’s no sound evidence that increased caffeine consumption results in significant or permanent weight loss 6).
Caffeine is one of the ingredients now being included in many of the weight loss supplements. It’s added for its energy enhancement, appetite suppressant, and “fat-burning” properties.
On September 1, 2015, the FDA issued warning letters to five distributors of pure powdered caffeine because these products are dangerous and present a significant or unreasonable risk of illness or injury to consumers. (Source 7)). Pure powdered caffeine products are potentially dangerous and have contributed to at least two deaths 8). The FDA advises consumers to avoid pure powdered caffeine. It is nearly impossible to accurately measure pure powdered caffeine with common kitchen measuring tools and you can easily consume a lethal amount.
The difference between a safe amount and a toxic dose of caffeine in these pure powdered products is very small. Safe quantities of these products can be nearly impossible to measure accurately with common kitchen measuring tools. Volume measures, such as teaspoons, are not precise enough to calculate how many milligrams of caffeine are in the serving size. Pre-existing conditions can intensify the effects of caffeine and make the product more dangerous for these individuals.
One teaspoon of pure powdered caffeine (100 percent caffeine) is equivalent to the amount of caffeine in about 28 cups of regular coffee. While consumers of caffeinated products such as coffee, tea, and soda may be aware of caffeine’s less serious effects – such as nervousness and tremors – they may not be aware that these pure powdered caffeine products are much more potent and can cause serious health effects, including rapid or dangerously erratic heartbeat, seizures and death. Vomiting, diarrhea, stupor and disorientation are also symptoms of caffeine toxicity.
Does it work ?
In a prospective cohort study 9) to assess the effect of weight change on the relationship between coffee and tea consumption and diabetes risk. The finding of that study found that for less than or equal to 60-years-old subjects, the risk of diabetes was significantly, negatively and independently associated with the consumption of ground-caffeinated coffee, ground-decaffeinated coffee and regular tea offers clues to the underlying causes of the reduction in diabetes risk. It suggests that each of these beverages contains constituents that are involved in reducing diabetes risk, and that are not contained, or not active, in the other two beverages. Caffeine appears to have been involved in the reduction of diabetes risk, possibly by inducing weight loss, because: (1) caffeine accounted for the significance of the negative association between diabetes risk and ground-caffeinated coffee, after the effects of ground-decaffeinated coffee and regular tea had been considered; (2) caffeine also accounted for the significance of the negative association between weight gain and ground-caffeinated coffee, after the effects of ground-decaffeinated coffee had been considered; and (3) the negative association between caffeine intake and diabetes risk was only significant for subjects with prior weight loss. These findings are consistent with the finding in several previously-published studies that caffeine induces thermogenesis 10), 11), 12) and stimulates lipid oxidation 13), 14), 15) in humans. Caffeine might thereby help individuals control their weight, and hence decrease diabetes-risk.
In addition, some studies found that even decaffeinated coffee may contribute to modest weight loss, suggesting that substances or factors besides caffeine may play a role in weight loss.
A series of four trials 16) was carried out to investigate the effects of caffeine and coffee on the metabolic rate and substrate utilization in normal weight and obese individuals. In the first trial 8 mg/kg caffeine was compared with a placebo in normal weight subjects. Metabolic rate increased significantly during the 3 hr after caffeine ingestion. While plasma glucose, insulin, and carbohydrate oxidation did not change significantly, plasma free fatty acid levels rose from 432 +/- 31 to 848 +/- 135 muEq/liter and were accompanied by significant increases in fat oxidation during the last hour of the test. In the second and third trials the effects of coffee providing 4 mg/kg caffeine were studied in control and obese subjects. Metabolic rate increased significantly in both groups; however, significant increases in fat oxidation were only observed in the control group. Plasma free fatty acids did not change in the obese. In the fourth trial, coffee was taken with a 3080 kJ meal. The thermic effect of the meal was significantly greater after coffee than after decaffeinated coffee and again fat oxidation was significantly greater after coffee. In conclusion caffeine/coffee stimulates the metabolic rate in both control and obese individuals; however, this is accompanied by greater oxidation of fat in normal weight subjects. Weight-loss dietary supplements with caffeine might help you lose a little weight or gain less weight over time. But when you use caffeine regularly, you develop a tolerance to it. This tolerance might lessen any effect of caffeine on body weight over time.
Is it safe ?
Caffeine is safe at low doses. But it can make you feel nervous, jittery, and shaky. It can also affect your sleep. At high doses (above about 400 milligrams [mg] a day for adults), it can cause nausea, vomiting, rapid heartbeat, and seizures. Combining caffeine with other stimulant ingredients can increase caffeine’s effects.
Caffeine is found in many beverages, including coffee, tea, energy drinks and colas; in products containing cocoa or chocolate; and in a variety of medications and dietary supplements, including supplements aimed at weight loss.
Although research about the connection between caffeine and weight isn’t definitive, there are a few theories about how caffeine might affect weight, including:
- Appetite suppression. Caffeine may reduce your desire to eat for a brief time, but there’s not enough evidence to show that long-term consumption aids weight loss.
- Calorie burning. Caffeine may stimulate thermogenesis — one way your body generates heat and energy from digesting food. But this probably isn’t enough to produce significant weight loss.
Study limitations : It is possible that subjects with weight loss, and hence lower diabetes risk, were also, coincidentally, prone to drinking ground coffee and regular tea, and that the prior weight loss caused the negative association between these beverages and diabetes risk. However, given that previous studies have yielded evidence supporting the weight-reduction potential of both regular tea 17) and caffeine 18), 19), 20) it seems more likely that the beverages themselves promoted the weight loss and hence the reduction in diabetes risk. In addition, some studies found that even decaffeinated coffee may contribute to modest weight loss, suggesting that substances or factors besides caffeine may play a role in weight loss.
The bottom line: Be cautious about using caffeine products to help with weight loss. When used in moderation (400 milligrams or less) by healthy adults, caffeine is generally safe. But too much caffeine might cause nervousness, insomnia, nausea, increased blood pressure and other problems.
Also keep in mind that some caffeinated beverages, such as specialty coffees, are high in calories and fat. So instead of losing weight, you might actually gain weight if you drink too many of these.
References [ + ]
|1.||↵||Dulloo AG, Duret C, Rohrer D, Girardier L, Mensi N, Fathi M, Chantre P & Vendermander J. Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-hr energy expenditure and fat oxidation in humans. Am J Clin Nutr 1999; 70: 1040−1045. – https://www.ncbi.nlm.nih.gov/pubmed/10584049?dopt=Abstract&holding=npg|
|2.||↵||Arciero PJ, Bougopoulos CL, Nindl BC & Benowitz NL. Influence of age on the thermic response to caffeine in women. Metabolism 2000; 49: 101−107. – http://www.metabolismjournal.com/article/S0026-0495(00)90888-6/pdf|
|3, 12, 14, 19.||↵||Astrup A & Toubro S. Thermogenic, metabolic, and cardiovascular responses to ephedrine and caffeine in man. Int J Obes Relat Metab Disord 1993; 17 Suppl 1: S41−S43. – https://www.ncbi.nlm.nih.gov/pubmed/8384179?dopt=Abstract&holding=npg|
|4.||↵||Bracco D, Ferrarra JM, Arnaud MJ Jequier E & Schutz Y. Effects of caffeine on energy metabolism, heart rate, and methylxanthine metabolism in lean and obese women. Am J Physiol 1995; 269: E671−E678. – https://www.ncbi.nlm.nih.gov/pubmed/7485480?dopt=Abstract&holding=npg|
|5.||↵||Katzel LI, Bleecker ER, Colman EG, Rogus EM, Sorkin JD & Goldberg AP. Effects of weight loss vs aerobic exercise training on risk factors for coronary disease in healthy, obese, middle-aged and older men. JAMA 1995; 274: 1915−1921. – https://www.ncbi.nlm.nih.gov/pubmed/8568984?dopt=Abstract&holding=npg|
|6.||↵||National Institutes of Health Office of Dietary Supplements – Dietary Supplements for Weight Loss Fact Sheet for Consumers – https://ods.od.nih.gov/pdf/factsheets/WeightLoss-Consumer.pdf|
|7.||↵||U.S. Food and Drug Administration – Pure Powdered Caffeine – https://www.fda.gov/food/dietarysupplements/productsingredients/ucm460095.htm|
|8.||↵||FDA Voice December 16, 2014 – Tragic Deaths Highlight the Dangers of Powdered Pure Caffeine – https://blogs.fda.gov/fdavoice/index.php/2014/12/tragic-deaths-highlight-the-dangers-of-powdered-pure-caffeine/|
|9.||↵||International Journal of Obesity (2005) 29, 1121–1129. doi:10.1038/sj.ijo.0802999 – Coffee, tea and diabetes: the role of weight loss and caffeine – http://www.nature.com/ijo/journal/v29/n9/full/0802999a.html|
|10, 13, 17, 18.||↵||Dulloo AG, Duret C, Rohrer D, Girardier L, Mensi N, Fathi M, Chantre P & Vendermander J. Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-hr energy expenditure and fat oxidation in humans. Am J Clin Nutr 1999; 70: 1040−1045. – https://www.ncbi.nlm.nih.gov/pubmed/10584049?dopt=Abstract&holding=npg|
|11.||↵||Arciero PJ, Bougopoulos CL, Nindl BC & Benowitz NL. Influence of age on the thermic response to caffeine in women. Metabolism 2000; 49: 101−107. – https://www.ncbi.nlm.nih.gov/pubmed/10647072?dopt=Abstract&holding=npg|
|15, 20.||↵||Bracco D, Ferrarra JM, Arnaud MJ Jequier E & Schutz Y. Effects of caffeine on energy metabolism, heart rate, and methylxanthine metabolism in lean and obese women. Am J Physiol 1995; 269: E671−E678. – https://www.ncbi.nlm.nih.gov/pubmed/7485480?dopt=Abstract&holding=npg|
|16.||↵||Am J Clin Nutr. 1980 May;33(5):989-97.Caffeine and coffee: their influence on metabolic rate and substrate utilization in normal weight and obese individuals.- https://www.ncbi.nlm.nih.gov/pubmed/7369170|