A:This perennial dessert favorite packs a big health punch. A 2006 study, for instance, found that consuming dark chocolate has cardiovascular benefits. Other studies have demonstrated that the flavanols in dark chocolate—compounds found in plants—also have antioxidant, anti-inflammatory, and even memory-boosting properties.
Most notably for athletes, dark chocolate increases the availability of nitric oxide in the blood, which improves blood flow and decreases blood pressure. Better blood flow means your muscles will get fuel and oxygen more efficiently, increasing endurance and decreasing recovery time.
Another study (in mice) found that nitric oxide, combined with exercise, led to significant muscle gain.
How much should you take? If you want to use dark chocolate to boost your endurance during a long workout, try eating 100 grams of it two hours before your workout. Researchers found that men who did so had higher plasma insulin and glucose concentration during a 2.5-hour bike ride, giving them more energy and quicker muscle repair.