Dark chocolate has been given quite the health halo over the last couple of years (See: Milk Chocolate vs. Dark Chocolate). Its main ingredient, cocoa, is packed with antioxidants, specifically flavanoids. Research has shown that it may reduce risk factors for heart disease, improve cognitive function, and lower cholesterol levels—and there might be even more good news.
A recent British study published in the Journal of the International Society of Sports Nutrition revealed that eating dark chocolate as a daily snack could help boost athletic performance. The study was based on the theory that dark chocolate may be similar to beetroot juice in containing a substance called epicatechin (a type of flavonol), which may increase nitric oxide production. Researchers split nine amateur cyclists into two groups. One group replaced one daily snack with 40 grams of dark chocolate and the other group with 40 grams of white chocolate (they alternated for two weeks each). When cycling at a moderate pace, they found the dark chocolate group used less oxygen and covered more distance in a two-minute flat-out time trial.
So, should we start stocking up on dark chocolate to improve our workout? Not so fast. Keep in mind this study was done on a very small sample size and only with cyclists, which makes it harder to make general recommendations. Additionally, 40 grams of dark chocolate has 217 calories, 12.6 grams of total fat, 2g protein, and 19.6 grams of sugar—a little too high in fat and sugar and low in protein for the average workout snack.
Bottom line: If you want to include two small dark chocolate squares of chocolate as part of a well-balanced diet, go for it. Numerous studies have confirmed its health benefits (Reasons Chocolate Is the Best). If you're looking for a noticeable difference in your athletic performance, maybe wait until there's more research. In the meantime, there are plenty of guilt-free ways to enjoy your chocolate kick.