More hot research!

We reported last year on a study that evaluated the effect of eating chilies on blood sugar levels and metabolism (Hot research! 7/14/06). Unfortunately, that study's results suggested only that the amount of insulin needed to control a person's blood sugar might be decreased after eating a meal containing chilies, but that the amount of energy the person burned - their basal metabolism - was unaffected.

In a follow-up study reported in the European Journal of Clinical Nutrition (2007;61(3):326-333), 36 volunteers were randomly assigned to a bland or chili-containing diet, then after four weeks of following that diet, they switched to the opposite diet for a further four weeks. The chili-containing diet included the equivalent of 30mg per day of capsaicin, the active ingredient in chilies.

At the beginning of the study and then again at the end of each diet period (at four and eight weeks), the subjects' blood pressure was tested and their cholesterol scores were measured via blood test. In addition, their basal metabolic rate (the amount of energy an individual burns while at rest) was measured.

The results are disappointing. Even a regular diet of chilies, as opposed to a one-time meal as in last year's study, had no effect on an individual's metabolism. Interestingly, the scientists note that the male volunteers had a slightly lower resting heart rate after four weeks of the chili diet as compared to the bland diet. (A higher resting heart rate can be a risk factor for heart disease, especially in white men.)

What this means for you

This is a small study, but one that's fairly well designed, and it certainly appears that it puts paid to the idea that eating chilies will raise your metabolism. You can still love spicy foods, though, and spicy foods like salsa are a great, low-calorie way to brighten up what might otherwise be boring food. Try some Pork Chops with Warm Tomatillo Salsa, Tenderloin with Harissa Sauce, or Tuna with Wasabi Pea Crust for a change of pace.

First posted: April 4, 2007