If you are thin in a normal diet, it is mainly because of poor digestion and absorption ability. First of all, we should regulate the spleen and stomach, eat a little food that warms the stomach and intestines, and try to give priority to digestible pasta. You can eat chicken gizzard-membrane, hawthorn and other things that strengthen the stomach and spleen. After that, we should pay attention to diet, eat less fried food, and finally exercise reasonably. On the one hand, exercise can promote digestion and absorption, on the other hand, muscle gain is also weight gain.