Dark chocolate contains a host of benefits for the body, both mentally and physically. It provides you with the needed stamina to perform strenuous workout routines while helping you build muscles and a healthy heart.

Scarlett Johansson is a foolproof testament of how dark chocolate does wonder to the body. Her personal trainers, the brothers Ryan and Eric Johnson, helped tone the actress so she can perform multiple stunts in her Marvel films including Avengers: Infinity War and Captain America: Winter Soldier. One advice the brothers, who are owners of the chain of Homage Fitness gyms in Miami, New York, and D.C., give their clients to boost their pre-workout energy is to snack on dark chocolate.

However, not just any dark chocolate will do. They suggest a good quality dark chocolate rich in antioxidants, preferably those that have 70 percent cacao, and having two to three pieces 10 to 15 minutes before a workout. The brothers say the snack releases dopamine, that part of the brain responsible for the reward-motivated behavior. It also gives gym buffs vasodilation, which is the pump they are after if they are looking to build muscles.

Dark chocolate is simply a great source of energy as much as it calms the nervous system since it stimulates the brain to release serotonin. It provides just the right amount of food inside your stomach before a workout.

"So we found that the little piece of dark chocolate doesn't have much weight to it but it's very nutrient-dense so it really provides the body with a lot of energy whilst still making you feel light in the stomach, allowing you to jump around and move."

Psychologically, eating dark chocolate before a workout gives you something to look forward to because of its benefits associated with exercise. The trainers call this a "positive feedback loop" in the brain.

Dark chocolate has been lauded as a healthy snack because of its benefits both physically and psychologically. It boosts weight loss and helps keep a healthy heart because of its antioxidants. It also enhances athletic performance, according to a 2016 study at London's Kingston University.

The study, which is published in the Journal of the International Society of Sports Nutrition, involved cyclists who are asked to eat dark chocolate before a cycling test to determine their level of stamina. The results showed that those who had the snack used less oxygen at a modern pace and covered more distance in a two-minute time trial. The researchers credit the epicatechin contained in the cacao bean that increases nitric oxide production in the body, which reduces oxygen consumption, thus allowing the cyclists to cover more distance.