Some foods contain molecules that increase your body's metabolism and stimulate fat burning. Red peppers contain a molecule called capsaicin that is shown to increase your fat-burning rate and promote weight loss. However, the capsaicin content in the different red pepper varieties differs extensively. Eating a pepper low in capsaicin will not affect your fat burning.
Red peppers come in hundreds of varieties, including bell, chili, cayenne, jalopeno and pimento. Bell or sweet pepper is a large bell-shaped pepper that comes in four varieties: green, yellow, orange and red. These are actually the same vegetable but harvested at different stages of maturity.
The scientific name of red peppers – capsicum – refers to the molecule found in most red peppers called capsaicin. Capsaicin is a colorless, flavorless and odorless natural substance that produces a burning sensation in the mucous membranes and gives spicy foods their heat and pungency. High concentrations of capsaicin will produce burning effects on your skin and so topical analgesics will usually contain the compound. In addition, muscle rubs and sports creams that seem to warm up the skin for pain relief will usually have capsaicin in them.
Capsaicin can increase your metabolism through thermogenesis, or production of heat. Capsaicins stimulate your body to burn calories as heat and improve your fat oxidation. According to a study published in the “American Journal of Clinical Nutrition,” eating 6 mg of capsaicins per day improved abdominal fat loss in men and women. Capsaicin can also suppress appetite. According to the "New York Times," eating hot sauce containing appetizers before meal decreased calorie consumption by 200 calories. Adding hot red peppers on your everyday dishes can therefore boost your metabolism and help manage your weight.
Bell Pepper and Capsaicins
Red peppers contain different amounts of capsaicins. According to the Union County College, the highest levels of capsaicins are found in the habanero peppers, which have a rating of 100,000 to 300,000 Scoville heat units. Bell peppers have a rating of 0 or 1 Scoville heat and do not contain significant amounts of capsaicins. Since red bell peppers have no heat, they are sweet and more favorable for most people. They contain high levels of vitamins and are a nutritious addition to any diet. However, eating red bell peppers will not improve your fat burning, unlike eating other red peppers.