The effect of losing weight by fasting exercise will not be better. The wrong idea is that fasting blood sugar is lower, and fat will be consumed faster during exercise, so that fat function can be used faster and better weight loss effect can be achieved. However, the final weight loss effect of exercise is determined by the total energy consumption. Sugar is the main energy-supplying substance in the central system of human body, and the blood sugar will decrease obviously on an empty stomach. Therefore, when you exercise on an empty stomach, because your blood sugar is at a low level, the excitability of the central nervous system of your body will first decrease, which will make it difficult for your body to complete exercise with moderate intensity or above for a long time, and eventually lead to a decrease in the total amount of exercise, and the total energy consumed by your body is less than that on an empty stomach, so the weight loss effect will not be good. And some obese people are accompanied by blood sugar regulation disorder. Fasting exercise is likely to increase their chances of hypoglycemia and increase their risk of sports injury.