Cayenne peppers contain capsaicin, a compound that some research has suggested may be effective at helping the body burn fat, notes Authority Nutrition. As of 2015, limited research also suggests that consuming capsaicin with a meal causes a reduction in the overall calorie intake of some individuals.
Capsaicin is the compound that lends cayenne pepper its hot, spicy flavor. When consumed, capsaicin promotes the release of catecholamine hormones such as adrenalin, norepinephrine and dopamine, according to Precision Nutrition. Upon the release of these hormones, associated with fight-or-flight response, the body increases its metabolic energy expenditure by moving stored fat molecules into the blood stream to power the muscle tissue.
One study performed on a group of 25 college students showed that eating capsaicin may reduce calorie intake at a meal, reports WebMD. During the test, examiners asked some of the subjects to eat meals containing capsaicin, while others ate meals that did not contain the compound. Four hours later, the subjects ate as much macaroni and cheese as they wanted. The subjects who had eaten the capsaicin meals ate an average of 66 fewer calories of macaroni than the non-capsaicin group. The capsaicin did not have an effect on people who already ate spicy foods, suggesting that people build up a tolerance for the compound over time.