If you felt a sense of calm and well-being the last time you devoured a piece of dark chocolate, there may be a scientific explanation behind it. In a study last year 30 people who complained about stress ate a little bit of dark chocolate every day for two weeks. In the end the most stressed-out participants showed the most improvement. Researchers found that dark chocolate might help lower your stress hormones.

And the benefits of eating dark chocolate don’t stop there. Dark chocolate is also rich in antioxidants called flavonoids (milk chocolate contains far less), which help your body fend off cancers and heart disease. And, in a study of 44 adults with high blood pressure, eating dark chocolate daily for several months resulted in lowered systolic and diastolic blood pressure levels.

While this is all excellent news for dark-chocolate lovers, it’s important not to go overboard in the name of health. Chocolate is high in calories and saturated fat, and eating large amounts can expand your waistline. Eat moderate portions a couple of times a week. Think of it as a way to reward yourself for waking up for an early morning run on the treadmill, eating a healthful dinner, or simply getting through the day.