Most of the very thin people have digestive tract diseases, first of all, to identify the cause, and actively treat the primary disease. Poor absorption of the gastrointestinal tract or food intake is too little, which can easily lead to malnutrition, very thin people usually meal principles to adhere to a small number of meals, diet time as regular as possible, the diet structure should be balanced, usually you can consume more easily digestible, high-protein, high-calorie food, such as chicken and duck, deep-sea fish, eggs, beef and mutton. At the same time, strengthen physical exercise, such as swimming, running, playing ball and other sports, through exercise can increase meal size, promote absorption and enhance physical fitness. If accompanied by gastrointestinal diseases, such as irritable bowel syndrome, gastroenteritis, etc., should be under the guidance of a doctor reasonable use of drugs, the representative drugs are mainly omeprazole, rectification, etc.. If necessary, perform colonoscopy and gastroscopy to exclude tumors and other chronic wasting diseases.