A New Diet Tool?

For those of us addicted to the buzz, the benefits of a good old cup of coffee are nothing new. But a recent study indicates that unroasted, or "green," coffee beans might do more than just help us start the day and stay awake: They may also help some people lose weight.

Raw, unroasted coffee beans contain a substance called chlorogenic acid (CGA), which can be extracted from the bean and sold as a supplement. According to research published in 2012, investigators in Bangalore, India followed 16 healthy overweight adults in a 22-week study, randomly assigning subjects to receive either a low (750 mg) or high dose (1050 mg) CGA extract, or a placebo for a period of six weeks, followed by a two-week washout period, before the next treatment period began. All participants were counseled about diet and exercise at their initial interview, and then were examined during subsequent visits, where they were asked about how well they'd complied with their diets.

The results showed that participants taking either the high or the lose dose CGA supplement—but not the placebo—reduced their weight, body mass index, (BMI, a measure of body fat based on height and weight) and body fat percentage.

What is it about green coffee beans that lead to weight loss? The exact mechanisms are unknown. It might be that the extract inhibits lipase (fat) or sugar absorption, or affects metabolism. Or it might be that green coffee beans decrease appetite, making people consume less food. Of course, it might also be that people who participate in weight loss studies are more careful about what they eat and how much they exercise!

What You Need to Know

Could coffee or CGA supplements help you lose weight? Many athletes find that a cup of joe perks up their performance, and many regular coffee drinkers say java dials down their appetites, at least temporarily. Some people say it's been effective in helping them lose weight, but they'll also tell you they watched their diet and increased their exercise. While most healthy people suffer no adverse effects from coffee (other than a case of the jitters and a little insomnia), it's important to let your doctor know if you intend to use CGA or caffeine supplements to lose weight.

Dennis Bley, DO, reviewed this article.



Joe A. Vinson, Bryan R. Burnham, and Mysore V. Nagendran. "Randomized, Double-Blind, Placebo-Controlled, Linear Dose, Crossover Study to Evaluate the Efficacy and Safety of a Green Coffee Bean Extract in Overweight Subjects." Diabetes Metab Syndr Obes 2012;5: 21-27. Published online 2012 January 18. doi:  10.2147/DMSO.S27665.