Cayenne Pepper May Burn Calories, Curb Appetite

April 27, 2010 -- Red cayenne pepper may help burn calories and curb appetite, especially in people who aren’t used to eating it, says a new study that was partly supported by the National Institutes of Health and the McCormick Spice Company.

The study found that about half a teaspoon of cayenne pepper either mixed in food or swallowed in a capsule helped normal-weight young adults burn about 10 more calories over a four-hour period, compared to eating the same meal but without the red pepper.

Pepper also decreased appetite, especially in people who said they didn’t already eat spicy foods.

Study researcher Richard Mattes, PhD, RD, distinguished professor of foods and nutrition at Purdue University in West Lafayette, Ind., thinks that the pepper is stimulating the trigeminal nerve, one of the main nerves in the head and neck.

“Chemesthesis is the term for chemical irritation, and that’s the sense that this work focused on,” Mattes says. “What we were interested in is, does activation of that system lead to increases in energy expenditure, alterations in appetite and food intake, and so on.”

"The appetite responses were different between those who liked red pepper and those who did not, suggesting that when the stimulus is unfamiliar it has a greater effect,” Mattes says in a news release.

Based on his study, Mattes says it appears that once a person gets used to the spicy foods, their effects start to wear off.

“So the question is, how long does the phenomenon last once you start using red pepper. And if it starts to diminish, how long do you have to wait to obtain the same benefits?” Mattes says. “Those are future studies. This was just our observation that the effect was bigger in people who were not regular users.”

The study is published in Physiology & Behavior.

Previous studies had tested the thermogenic, or calorie-burning, effects of red pepper but had used quantities that were too large to be practical for most people.

Testing the Effect of Pepper

For the study, researchers recruited 25 men and women from a college campus. The average age of study participants was 23. The average BMI (body mass index) was 22.

Thirteen of the study participants reported regularly eating spicy food before the study, while 12 didn’t eat hot spice.

Participants were asked to complete a total of six study visits, each separated by a week.

They were also instructed to avoid alcohol, caffeine, or strenuous exercise before their lab tests.

Participants fasted for 12 hours before coming for a lab visit in which their resting energy expenditure, core body and skin temperatures, and appetites were measured.

They were then randomly assigned to eat meals with or without red pepper added. There were three visits with red pepper and three without.