Advertisers claim the belts promote fat loss in the "trouble" areas of your body, like your abs, back of your arms, and thighs. The belts heat up like a sauna, and increase heat and perspiration at these points, supposedly allowing you to "sweat" off the fat.
You cannot "spot reduce" fat on your body. Through diet and exercise, you lose fat all over your body at a consistent rate.
The sauna belt is like the electro-belt popular in the 1990s; the device does not work. There is no substitute for disciplined diet and quality exercise. Full body saunas do increase body heat and calorie expenditure, but sauna belts are too small to lower your body's fat reserves.
Increasing your body heat is a proven way to expedite the weight loss process. Wrestlers and boxers use body heating techniques, sometimes to dangerous extremes. Go jogging with a sweat suit on, and/or exercise outside at noon, the hottest time of day. Drink plenty of water to prevent dehydration, and stop exercising if you feel faint, dizzy, or intense pain. Remember, losing fat takes time and diligence. Always consult a physician before beginning any exercise routine.