Dark Chocolate For the same reason that dark chocolate can help boost your metabolism, it can help you sleep better, too. Compounds in dark chocolate have been found to reduce the production of the hormone cortisol in the brain. This “stress hormone” is associated with weight gain, and the more stressed you are, the harder it is to quiet your thoughts at night. Eat it throughout the day to help you feel more relaxed, not right before you go to bed, since it does contain a little bit of caffeine.