Post by Michaeleen Doucleff, The Salt at NPR Food (6/14/13)
The diet world has a new golden child: green coffee extract.
A "miracle fat burner!" "One of the most important discoveries made" in weight loss science, the heart surgeon Dr. Mehmet Oz said about the little pills — which are produced by grinding up raw, unroasted coffee, and then soaking the result in alcohol to pull out the antioxidants.
But alas, the history of dieting is littered with failed concoctions and potions. And now, a study in mice casts doubts on green coffee's weight-loss benefits — and even offers some preliminary evidence that it could be harmful.
The main ingredient in green coffee extract — an antioxidant called chlorogenic acid — didn't help obese mice shed the pounds over a 12-week period, scientists at the University of Western Australia reported in the Journal of Agricultural and Food Chemistry. Instead, the compound gave the little rodents the early symptoms of diabetes: The animals were less sensitive to insulin and had higher blood-sugar levels between meals, compared with their overweight comrades who didn't get the antioxidant.