Possibly one of the greatest inventions in culinary history, chocolate possibly seems to have health benefits over and beyond spreading happiness. In fact, perhaps counter-intuitively, dark chocolate has he power to help fight obesity and type 2 diabetes. The key is a type of antioxidant—a compound that helps prevent certain kinds of cell damage—called a flavonol, in particular flavonols of a type referred to as "oligomeric procyanidins." In a study, these flavonols helped keep weight down even in experimental specimens given diets high in fat. Preventing obesity is an important part of avoiding type 2 diabetes, but dark chocolate has a direct effect on that as well. The same compounds were found to improve insulin utilization, meaning the body processes glucose more efficiently, avoiding type 2 diabetes.
While the compound was studied in laboratory animals, there is evidence that it works in human beings as well. In particular, teenagers who eat lots of chocolate generally have lower levels of body fat than their diets (beyond chocolate) might be expected to lead to. Adolescents in Europe who reported on surveys high levels of chocolate consumption were found to have lower BMIs and smaller waists regardless of how much exercise the were getting. An earlier study had found similar results among adults, that regular chocolate-eaters are leaner than those who indulge only rarely. The teen years, however, are where eating habits often develop, and overall health during that period often has lasting effects.
Researchers say the secret to why chocolate is so healthful is in the stomach. Humans have bacteria called gut microbiota to thank for making chocolate something so beneficial. These bacteria, which line the intestinal tract and other parts of the digestive system, play a vital role in digestion in general, and some of them eat chocolate. When they do, they ferment it, seizing on the sugars and producing anti-inflammatory chemicals. The also make it possible for the flavonols to be digested.
The anti-inflammatory compounds mean dark chocolate is also good for hear health. These chemicals make the blood vessels wider and more flexible, and preventing blood cells from adhering to the walls, lowering stroke risk.