A body slimming vest is designed to be worn close to the skin, typically as an undergarment. The vest may use materials that compress the body and create a slimmer appearance. Some body slimming vests also claim to promote weight loss by raising body temperature, increasing sweating, and stimulating weight loss in the abdominal area. However it's important to note that there is no scientific evidence to support these claims and the weight loss from sweating is temporary and not sustainable.