In the study Joe Vinson's team described how a group of overweight or obese people who consumed a few milligrams of ground green coffee beans each day lost about 10 per cent of their weight.
" Taking multiple capsules of green coffee extract a day - while eating a low-fat, healthful diet and exercising regularly - appears to be a safe, effective, inexpensive way to lose weight," said Vinson, who is with the University of Scranton.
The study involved 16 overweight or obese people aged 22-26 years who took capsules of the extract or capsules containing a placebo, an inactive powder, for a total of 22 weeks. The subjects alternated between a low dose and a higher dose of the extract.
The low dose consisted of 700mg of the coffee extract, and the high dose was 1,050mg. It was a so-called "crossover" study in which people cycled through the two doses and the placebo, each for six weeks. Such studies have advantages because each person serves as his or her own "control," improving the chances of getting an accurate result.
All of the participants were monitored for their overall diet (calories, food eaten, etc.) and exercise over the study period. "Their calories, carbohydrates, fats and protein intake did not change during the study, nor did their exercise regimen change," Vinson said.
Participants lost an average of 7 kilos during the 22 weeks of the study. It included an average of a 10.5 per cent decrease in overall body weight and a 16 per cent decrease in body fat. Vinson noted that weight loss might have been significantly faster, except that participants received the placebo and the lower dose of green coffee extract for part of the study period.