Green coffee beans may be effective for weight loss, partly because they seem to regulate blood sugar.
Green coffee beans are unroasted beans from coffee plants. Most notably, these beans are high in chlorogenic acid (CGA), which is believed to aid fat loss by:
- Reducing blood glucose levels, which promotes the burning of fat for energy.
- Enhancing fat metabolism. CGA has been shown to suppress fat absorption and increase fat metabolism in the liver.
Green coffee beans (GCB) are beans from coffee plants (genus Coffea) that have not undergone the roasting process. They are known for their high chlorogenic acid (CGA) content, which is significantly reduced by roasting. Recent research suggests that chlorogenic acid could benefit cardiovascular health and act as a fat burner.
Despite this, green coffee beans have seen some controversy. Most notably, popular TV personality Dr. Oz touted GCB extract as a miracle weight-loss drug, citing a questionable study to support his claims. This study was later retracted as the two researchers who were paid to write the paper could not verify the data. Meanwhile, Dr. Oz was criticized by a panel of U.S. senators for his promotion of dubious weight loss products.
How Green Coffee Bean May Help With Fat Burning
The main active ingredient in green coffee beans – chlorogenic acid (CGA) – is believed to work in two main ways.
Reduce blood glucose
First off, CGA appears to suppress the activity of an enzyme called glucose-6-phosphate, which is used by the body to release glucose into the bloodstream. Second, it also appears to inhibit the absorption of glucose in the small intestine. These two bio-activities result in lower blood glucose levels, promoting the release of fat from fat cells to make up for the lower glucose and leading to weight loss.
Improve fat metabolism
Moreover, CGA may also inhibit the absorption of fat and increase the body’s usage of fat for energy by activating fat metabolism in the liver, promoting further fat loss.1
Green Coffee Bean’s Fat Burning Benefits
Green coffee bean extract is touted as a natural weight loss supplement. Despite the Dr. Oz controversy, clinical research has demonstrated that green coffee bean extract helps with weight loss by promoting the burning of fat and inhibiting its absorption.
Having said that, researchers stress the importance of further research for several reasons: existing studies may not be of highest quality, use different research methods, and lack long-term data.
Animal & Petri Dish Research
Animal and isolated cell studies of green coffee bean have shown promising results for its use in weight loss:
- Green coffee bean extract (GCFE) appears to significantly reduces fat accumulation and improve insulin resistance in mice2
- Decaffeinated green coffee bean extract (DGCE) Svetol appears to stimulate the release of free fatty acids when applied to isolated human adipocytes (fat cells)3
Human clinical trials corroborate the findings of animal and petri dish studies.
This randomized trial looked at the effect of decaffeinated green coffee bean extract Svetol on weight loss. Fifty overweight individuals were split up into two groups for 60 days: group one received a placebo twice daily, while group two received Svetol instead. At the end of the experiment, the Svetol group lost an average of 4.97 kg vs only 2.45 kg for the placebo.
- The researchers concluded that “Svetol® has demonstrated its validity and could be used to aid the dietetics prescription in a useful and positive manner”4
This study was performed in two parts: first, the researchers compared the effect of normal coffee versus coffee enriched with chlorogenic acid (CGA) on glucose absorption in 12 volunteers with normal body weight. They found that coffee containing 90-100 mg CGA appeared to reduce glucose absorption by 6.9%, leading to lower blood glucose levels.
Second, they looked at the weight loss effect of normal coffee versus CGA-enriched coffee, taken as part of a regular diet in 30 overweight and obese individuals. Each group drank a total of 5 cups a day, with the CGA group consuming a total of 450-500 mg CGA daily.
They found that the group taking CGA-enriched coffee lost 3.6% of their body fat after 12 weeks, versus 0.7% in the normal coffee group.
- The researchers concluded that: “chlorogenic acid enriched instant coffee appears to have a significant effect on the absorption and utilization of glucose from the diet. This effect, if the coffee is used for an extended time, may result in reduced body mass and body fat”5
This study looked at whether chlorogenic acid (CGA) could improve cardiovascular health. Twenty-three healthy men and women were split up into 2 groups, the first receiving water (placebo), while the second received 400mg of CGA dissolved in water. The major finding was thatxcv the CGA group had significantly lower blood pressure.
- The researchers concluded that “we found an acute blood pressure-lowering effect of chlorogenic acid”6
This paper reviewed a total of 6 existing trials that studied the effects of GCBE on weight loss. This review found that GCBE did have a significant weight loss effect, however the effect was only present for obese and overweight individuals, whereas people with normal weight saw no benefits.
- The researchers concluded that: “the results of our meta-analysis reveal that GCBE may be an effective nutraceutical in reducing weight in overweight/obese adults” 7
Dosage for Fat Burning
- The ideal dosage appears to be 1-1.2 grams of green coffee bean extract daily, which translates into about 400-600 mg of chlorogenic acid, as it makes up roughly 50% of the extract
- Most GCBE supplements suggest taking 1-2 800 mg capsules daily
Supplements in Review Says
- Green coffee bean extract 1-1.6 grams daily.
Green coffee bean extract is a solid addition to a weight loss regimen. Although researchers stress the need for more high-quality clinical trials, existing data suggests that GCB extract helps overweight and obese individuals burn fat.
Most clinical studies use 400-500 mg CGA, which translates into 1 g GCB extract. Given that the large majority of GCB extracts supply 50% CGA, 1 g should be enough to see beneficial effects. In addition, you can try upping your dose to the 1.6 g recommended by most GCB extract supplements.
- Shomida H., Seki E., Aitani M. Inhibitory effect of green coffee bean extract on fat accumulation and body weight gain in mice. BMC Complement Altern Med. 2006; 6: 9. ↩
- Song SJ, Choi S., Park T. Decaffeinated Green Coffee Bean Extract Attenuates Diet-Induced Obesity and Insulin Resistance in Mice. Evidence-Based Complementary and Alternative Medicine. Volume 2014 (2014), Article ID 718379, 14 pages ↩
- Flanagan J., Bily A., Rolland Y., Roller M. Lipolytic Activity of Svetol®, a Decaffeinated Green Coffee Bean Extract. Phytotherapy Research Volume 28, Issue 6, pages 946–948, June 2014 ↩
- Dellalibera O., Lemaire B., Lafay S. Svetol®, green coffee extract, induces weight loss and increases the lean to fat mass ratio in volunteers with overweight problem. Phytotherapie, vol. 4, no. 4, pp. 194–197, 2006. ↩
- Thom E. The Effect of Chlorogenic Acid Enriched Coffee on Glucose Absorption in Healthy Volunteers and Its Effect on Body Mass When Used Long-term in Overweight and Obese People. J Int Med Res.2007 Nov-Dec;35(6):900-8. ↩
- Mubarak A. et al. Acute effects of chlorogenic acid on nitric oxide status, endothelial function, and blood pressure in healthy volunteers: a randomized trial. J Agric Food Chem.2012 Sep 12;60(36):9130-6. doi: 10.1021/jf303440j. Epub 2012 Sep 4. ↩
- Hausenblas H. and Huynh B. Effects of Green Coffee Bean Extract on Weight Loss. Natural Medicine Journal. March 2014 Vol. 6 Issue 3 ↩