What the results suggest, says Andrew Neilson, an assistant professor at Virginia Tech and the senior author of the mouse study, is that “there is something going on with cocoa in the colon,” but what that means for chocolate lovers is not clear. Future experiments, he hopes, will tease out why one flavonol group impeded weight gain and the others did not. Do not hold your breath for a cocoa-based diet pill anytime soon, though. Cocoa’s biochemical impacts are “extremely complex,” he says.