These possible benefits of coffee consumption have been reported to be due to coffee's content of caffeine, antioxidants, and other components. However, the research to date is sparse and shows inconsistent results, alluding to the need for continued research into the possible weight loss benefits of coffee. Two such studies were recently published.
In the first study (free to download), weight loss researchers conducted a review and analysis of previously published human clinical trials on weight loss and green coffee extracts[1]. Green coffee extracts are typically rich in a number of antioxidant polyphenols including chlorogenic acid. Animal studies with green coffee extracts have suggested that they might support normal blood sugar health and normal blood lipid health through several different mechanisms. The study investigators examined the results of 3 randomized, human clinical research studies on the effectiveness of green coffee extracts on weight loss. They reported that regular consumption of green coffee extracts was significantly linked to a reduced body weight (about 5 pounds versus control subjects); however, the results were highly variable. The results of this analytical study suggest that green coffee extracts might have a place in one's weight loss program, but so far the benefits appear modest and vary widely.
In a second weight loss study, researchers asked 54 adult, overweight men and women to consume a beverage that either contained coffee mannooligosaccharides (4 grams/day) or did not contain them as part of a weight maintenance program[2]. The study volunteers consumed their beverage 2 times each day for 12 weeks. For this study, the weight loss researchers measured body composition at the start and end of the study as well as body weight and measures of appetite and feelings of fullness each week during the study. The weight loss researchers reported that men consuming coffee mannooligosaccharides daily for 12 weeks had a reduced body volume, lower body fat, and less belly fat than men consuming the placebo beverage. These benefits were not observed in the women volunteers.
These two new weight loss papers suggest that coffee extracts might support healthy weight loss and body composition changes; however, these results varied greatly and benefits were not observed in all groups. Further research is clearly needed to determine the effectiveness of these coffee components for healthy weight loss and body composition.