Have cereal for breakfast. It is best to eat some high-quality protein for lunch, such as chicken, fish, lean meat and beef. Their calories are very low, about 140 calories, which is lower than the 170 calories contained in one or two grains. Moreover, if people don't take enough protein when they lose weight, their metabolism will decline, which will affect the effect of losing weight. Losing weight must be scientific and reasonable, otherwise it will not be easy to lose weight but will come back.