Never, losing weight depends on reducing energy intake and consuming excess energy. The reason of obesity is that intake exceeds consumption, and energy accumulation is fat storage. Seasonal belts can't help you consume excess energy, so you can't lose weight. Also, for obese people, wearing a belt will tie excess fat around the waist and stretch the ribs for a long time, causing fatal rib eversion. For losing weight, my advice is to drink a cup of black coffee every morning, green tea during the day, eat less carbohydrates and energy, eat more vegetables and exercise, and eat low-fat meat, fish, beef and chicken.