One of the most discussed weight loss supplements on the market today is green coffee bean extract. Personalities such as Dr. Oz, and popular media have discussed promising results without actual endorsement of any specific products. I took a closer look at recent literature on the efficacy of the extract to find out if it was hype or legit.
To learn more about the science behind the weight loss claims, I reviewed the research article, “Randomized, double-blind, placebo-controlled, linear dose, cross-over study to evaluate the efficacy and safety of a green coffee bean extract in overweight subjects (1). In this study, green coffee bean extract marketed as GCAⓇ and manufactured by Applied Food Sciences Inc., showed significant results in reducing weight, body fat percentage, and BMI in sixteen people who had an average BMI of 26, which categorized them as “overweight.” Subjects consumed the supplement at a high dose, low dose, and then using a placebo for a total of 22 weeks. The study of this design worked well in that each subject experienced the different dosages and also used a placebo so that they acted as their own “control.”
Coffee beans have been researched in weight loss studies because they contain specific compounds that have been linked to improved glucose metabolism by the liver, and their caffeine content. One of these compounds is chlorogenic acid (CGA) the active ingredient in green coffee bean extract. Green coffee beans contain the largest amounts of CGA found in plants, ranging from 6 to 12% (3) making them an ideal weight loss solution if their effectiveness is proven.
CGA is composed of several individual phenolic compounds, the concentrations of which vary depending upon the degree that coffee is roasted. The longer a coffee bean is roasted the lower the levels of CGA. Previous research using CGA consumption in rats has improved glucose metabolism demonstrated by significantly lower levels of triglycerides after CGA supplementation. High triglyceride levels put one at risk for type 2 diabetes and heart disease. Caffeine promotes weight loss by inhibiting the enzymes and hormones related to the storage of fat while stimulating the breakdown of fat, when carbohydrate is not readily available.
The current study showed an average weight loss of 8 kg (17.6 lb) over 22 weeks with a varying dose. This is high compared to 2.5 – 5 kg (5.5 – 11 lb.) in unpublished studies that used human subjects. The average 8 kg weight loss is significant in that it moved six subjects from overweight to normal BMI, while consuming an average of 2400 calories. However, looking more closely at the study design shows that the average weight loss taking 1050 mg/day for six weeks was 4 – 9 lb, and average weight loss taking 700 mg/day for six weeks was 3 – 7 lb. Side effects did not present in the current study, however others have cited instances of an abnormal increase in heart rate and increase in systolic blood pressure.
SvetolⓇ green coffee bean extract manufactured by Berkem/Naturex has been used in previous research (2). This brand is distributed in the United States by Reserveage Organics contains 200 mg green coffee extract and 90 mg CGA (45%). If taken within the low range used in the current study (700-800 mg/day), and for a minimum of six weeks would require 4 capsules/day and three, 60 capsule bottles costing $30 each.
As with most supplements, ingredients and the amount of each contained per serving is not always accurate. This was found recently through testing by consumerlab.com. When shopping for green coffee bean extract pay attention to the amount in mg of CGA’s and percentage of caffeine. For maximum benefit, a minimum of 45% CGA’s are recommended. The amount of caffeine varies per extract and should be considered if you are sensitive to caffeine.
Should athletes use green coffee bean extract? First, keep in mind that research has only been conducted on pre-obese and obese subjects, not athletes or people who are trying to drop five pounds for performance gains. For any level of athlete the two concerns are total caffeine intake and contamination. If you don’t currently drink coffee or energy drinks that contain caffeine, it could be used short term. I would not recommend using it in conjunction with other caffeinated beverages because any increase in energy that excessive amounts of caffeine provide, may lead to lingering fatigue in the future. The possibility of contamination makes all supplements a risk. Elite athletes should not need a weight loss supplement if their training plan and recovery are methodical. If you are just getting off the couch and need to lose weight for health reasons, it is up to you to decide if the cost and risk are worth it. Short term use to initiate weight loss may help with initial motivation and lifestyle changes, but I would not recommend taking it longer than 18 weeks since that is the longest duration used in trials.
1 Vinson, J.A., Burnham, B.R., Nagendran, M.V. Randomized, double-blind, placebo-controlled, linear dose, cross-over study to evaluate the efficacy and safety of a green coffee bean extract in overweight subjects. Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy, 2012, 1(17):5,21-27.
2 Thom, E. A randomized, double-blind, placebo-controlled trial of a new weight-reducing agent of natural origin. J Int Med Res., 2000;28:229–233.
3 Farah, A., de Paulis, T., Trugo, L.C., and Martin, P.R. Effect of Roasting on the formation of chlorogenic acid lactones in coffee. J Agric Food Chem., 2005,53(5):1505-13.
4 Monteiro, M., Farah, A., Perrone, D., Perrone, L.C., and Donangelo, C. Chlorogenic acid compounds from coffee are differentially metabolized in humans. J. Nutr., 2007,137(10):2196-2201
Regina Hammond has a Master’s Degree in Sports Nutrition and works for Trismarter Triathlon Coaching and Nutrition (http://www.trismarter.com). She assists athletes with their training & race day nutrition plans, sorting through the chaos of sports supplements, debunking weight loss fads, and periodized fueling plans. Staying abreast of the latest research she believes in an individualized, practical approach to nutrition.