Snacking on dark chocolates daily may help give sports enthusiasts an extra edge in their fitness training, a new study led by an Indian-origin researcher has claimed.
Researchers found that dark chocolate provides similar benefits to beetroot juice, taken regularly by elite athletes after studies showed it can improve performance.
"Beetroot juice is rich in nitrates, which are converted to nitric oxide in the body. This dilates blood vessels and reduces oxygen consumption - allowing athletes to go further for longer," said Rishikesh Kankesh Patel, a postgraduate research student at Kingston University in the UK, who led the study.
The researchers wanted to find out whether dark chocolate could provide a similar boost, as it contains a substance called epicatechin - a type of flavanol found in the cacao bean, that also increases nitric oxide production in the body.
To test the theory, Patel carried out the study with a group of nine amateur cyclists.
After undergoing initial fitness tests to establish a baseline for comparison, the participants were then split into two groups.
The first group was asked to replace one of its normal daily snacks with 40g of a dark chocolate known to be rich in flavanols for a fortnight, while the other participants substituted 40g of white chocolate for one of their daily snacks as a control.
The effects of the athletes' daily chocolate consumption were then measured in a series of cycling exercise tests.
The cyclists' heart rates and oxygen consumption levels were measured during moderate exercise and in time trials.
After a seven-day interval, the groups then switched chocolate types and the two-week trial and subsequent exercise tests were repeated.
The study found that after eating dark chocolate, the riders used less oxygen when cycling at a moderate pace and also covered more distance in a two-minute flat-out time trial.
Patel said the results opened the door for more research which could eventually lead to dark chocolate becoming a staple part of endurance athletes' diets.
"Both dark chocolate and beetroot juice are known to increase nitric oxide, which is the major mechanism we believe is behind these results," Patel said.
"We found that people could effectively exercise for longer after eating dark chocolate - something that's not been established before in this way," he said.
The study was published in the Journal of the International Society of Sports Nutrition.
