How it Works
The secret to pepper's fat-blasting power lies in an alkaloid substance called capsaicin, which is also the source of the hot flavor. Not only does capsaicin ignite your mouth, but it may actually cause your body to heat up so that you burn calories faster.
The capsaicin/temperature link may be explained by the activity of brown fat. Most of the fat in our bodies is white, and excess levels of white fat are what cause people to become overweight or obese. In contrast, brown fat makes up a very small percentage of total fat (not all people may even have it), and is highly active as it works to regulate body temperature. Experts used to think that only babies have brown fat and they lose it growing up; now we know that adults also have brown fat, and can even build new brown fat cells.
In animal studies on hot peppers and weight loss, subjects demonstrated higher levels of brown fat activity after exposure to capsaicin. Although animal studies do not accurately predict results among people, it's possible that hot peppers also increase human metabolism by activating brown fat.
There also may be hope for people who desire similar effects without having to eat spicy foods, although research is still in the beginning stages. A small study published in the American Journal of Clinical Nutrition revealed that young men who had previously demonstrated brown-fat activity burned slightly more calories in the hour after taking capsinoids, which are capsaicin-like substances found in a unique variety of sweet pepper. Capsinoids don't taste hot, but this study suggests they may have similar thermogenic effects as spicy foods.
Regardless of the mild metabolism-boosting effects of peppers, the most effective way to slim down is to reduce caloric intake and increase physical activity. Peppers won't make up for overeating, just give you a minor boost.
Other Benefits of Hot Peppers
Weight loss aside, hot peppers come with plenty of health benefits. They contain even more vitamin C than citrus fruits, and more vitamin A than carrots. The capsaicin also induces a rush of endorphins, creating a boost in mood that keeps many pepper-lovers coming back for more. Capsaicin is also widely used as a topical pain reliever, and some research shows that ingesting the substance may help stave off prostate cancer.
Ranking the Heat
Heat from peppers is ranked using the Scoville scale: the higher the Scoville number, the higher the capsaicin content. Peperoncinis and pimientos are at the bottom rung with scores of 100 to 500, while the hottest peppers, such as ghost chilies, rank among 1 million Scoville units. Jalapenos, as hot as they may appear, lie near the bottom of the chart with 2,500 to 8,000 Scoville units.
Nina Kate is a certified fitness nutrition specialist through the National Academy of Sports Medicine (NASM). She also studied journalism at the University of California, Los Angeles (UCLA), and has contributed to numerous major publications as a freelance writer. Nina thrives on sharing nutrition and fitness knowledge to help readers lead healthy, active lives. Visit her wellness blog at BodyFlourish.com.