Although previous studies have suggested that capsaicin – the compound that makes most chilies taste hot – may reduce hunger and increase energy expenditure, the researchers behind this latest study, published in Physiology & Behavior, said that most amounts tested would not be acceptable for most Americans, even though spicy/hot has been reported as being one of the most appealing flavors in the United States.
Moreover, while other research has also tested the effect of capsaicin consumption via supplements, this study examined the effect of relatively small amounts of cayenne pepper – about half a teaspoon – in foods, and found that actually tasting the pepper may increase its efficacy for appetite suppression and boosting energy expenditure.
Distinguished professor of foods and nutrition and lead author of the study Richard Mattes said: "We found that consuming red pepper can help manage appetite and burn more calories after a meal, especially for individuals who do not consume the spice regularly. This finding should be considered a piece of the puzzle because the idea that one small change will reverse the obesity epidemic is simply not true. However, if a number of small changes are added together, they may be meaningful in terms of weight management."
The study examined the effect of cayenne pepper consumption on the appetite of 25 non-overweight people over a six-week period, 13 of whom liked spicy food and 12 who did not. The researchers assessed that those who did not like red pepper preferred 0.3 grams on average, compared to regular spice users who preferred 1.8 grams.
Overall, consumption of the spice increased core body temperature and led all study participants to burn more calories, while those who were infrequent consumers of spicy food also said they were also less hungry after eating the spice and experienced fewer cravings for salty, fatty and sweet foods.
“Once it becomes familiar to people, it loses its efficacy,” Mattes said. “The finding that there is a difference between users and non-users is novel and requires further study to determine how long it will be effective and how to adjust the diet to improve continuous effectiveness."
Mattes also warned against consuming capsaicin in supplement form in an effort to impact appetite and energy expenditure.
"It turns out you get a more robust effect if you include the sensory part because the burn contributes to a rise in body temperature, energy expenditure and appetite control,” he said.
The researchers concluded that concentrations of the spice in foods, reflecting taste preferences, could be more effective than supplements for weight management.
Source: Physiology & Behavior
102 (2011) pp. 251-258
“The effects of hedonically acceptable red pepper doses on thermogenesis and appetite”
Authors: Mary-Jon Ludy and Richard D. Mattes