Usually when you start to exercise, the fat has already been burned, and it is not the case that you have to exercise for 30 minutes in order to burn fat. At the beginning of exercise is mainly in the blood glucose consumption for energy supply, and fat decomposition for energy supply is supplemented, is not no fat consumption. It is just that when you start exercising, you consume less fat, and the ratio of consumption of the two is different. Under normal circumstances, 30 minutes before exercise is mainly the first consumption of glucose in the blood to provide a short period of energy, at the same time the body will also mobilize a small amount of fat consumption to provide energy. When the glucose in the blood is consumed, the body will mobilize a lot of fat to provide the required exercise energy, and at this time, fat consumption is the main consumption. To summarize, exercise is fat-burning. People who need to exercise are advised to do so under professional guidance.