If you want to get fat, you must first understand why you are not fat. First, you are malnourished and have an irregular diet. Second, it must be bad stomach. If you don't absorb the best things, your stomach will be zero. Third, the energy you eat in your stomach is less than the energy you consume in a day, which is unbalanced. I hope you can consider these aspects. According to your requirements, you can't be fat, otherwise you will gain weight and improve your physical fitness. Then, eat more foods with high carbohydrate content in protein, and eat less junk food and greasy food with high fat and sugar, followed by moderate exercise to keep fit, and finally good gastrointestinal conditioning. It is recommended to drink probiotics. It is a kind of beverage granule containing prebiotics. He is a microorganism that protects the intestines and helps the intestines digest and absorb energy. I know a good imported probiotic raw material, and I am drinking it myself.