Disliking Red Pepper Increases its Appetite Effects

WEST LAFAYETTE, Ind. Red pepper reduced appetite, especially in those who don't normally eat spicy foods, in a new study from Purdue University (Physiol Behav. 2011 Mar 1;102(3-4):251-8).

Previous studies have found capsaicin, the component that gives chili peppers their heat, reduces caloric intake, but only in high doses (up to 10 g/meal) most would not be eating in a typical meal (about 1 g/meal).

Twenty-five healthy, lean men and women (aged 23.0 ± 0.5 years, body mass index [BMI] 22.6 ± 0.3) participated in this randomized crossover trial. Half of them (13) considered themselves spicy food users, while the others (12) did not. They were broken into three groups: one group consumed a standardized quantity (1 g), another group ate their preferred quantity (regular spicy food users 1.8 ± 0.3 g/meal, nonusers 0.3 ± 0.1 g/meal) and the final group ate no red pepper.

Researchers reported energy expenditure and core body temperature were greater, and skin temperature was lower, after subjects ate 1 g red pepper versus the non red pepper group. Respiratory quotient was lower after the preferred red pepper dose was ingested orally, compared to in capsule form, which suggests red peppers effects on energy balance stem from a combination of metabolic and sensory inputs, and that oral exposure is necessary to achieve its maximum benefits.

They also reported caloric intake was lower after eating 1 g red pepper than not eating red pepper for those who dont like spicy foods, but not in regular users. Preoccupation with food, and the desire to consume fatty, salty and sweet foods were also decreased more in non regular users than users after a 1 g. This suggests that individuals may become desensitized to the effects of red pepper with long-term spicy food intake.

"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," said Richard Mattes, distinguished professor of foods and nutrition who collaborated with doctoral student Mary-Jon Ludy on the study. However, if a number of small changes are added together, they may be meaningful in terms of weight management. Dietary changes that don't require great effort to implement, like sprinkling red pepper on your meal, may be sustainable and beneficial in the long run, especially when paired with exercise and healthy eating."

She also added, "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. Once it becomes familiar to people, it loses its efficacy. 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."

The study was funded by the National Institutes of Health under the Ruth Kirschstein National Research Service Award and by the McCormick Science Institute.