1. Goal setting: The minimum weight is generally set at 90% of the ideal weight. The rate of weight gain is 2-3 pounds/week for inpatients and 0.5-1 pounds/week for outpatients. Intake is usually started at 30-40kcal/kg/day (approximately 1000-1600kcal/day) and must continue to increase. During the weight gain phase, some patients may consume as much as 70-100kcal/kg/day. Patients who throw away food, vomit or exercise excessively or have non-exercise exertion such as fidgeting need higher caloric intake. 2. Develop recipes: give easily digestible, highly nutritious, high-quality food, with animal protein as more than 1/2 of the total protein. When the patient’s BMI <15, add 250-500mg/day of Nengye Energy Nutrition Solution, or add protein powder. 3.Giving mode: The lighter ones are mainly for dietary adjustment, eating according to the recipe and gradually increasing the amount of food. In severe cases, the diet can be liquid or semi-liquid at the beginning, without adverse reactions, the diet can be gradually changed to soft rice, etc. If the digestive function is very poor, those who cannot eat actively can be fed slowly by nasal feeding or intravenous nutrition, and if necessary, blood, plasma or albumin can be transfused repeatedly. However, patients with anorexia nervosa are prone to infections due to wasting and compromised immunity. Only when the patient does not cooperate with oral intake, health, life safety and recovery are threatened, the application of nasal feeding or intravenous nutrition mode is considered. 4.Limit the amount of activity: the early feeding of supplementary nutrition is less, and the activity should be limited. Consideration must also be given to the possible risk of fracture and heart failure in some patients. For those with severe low body weight, the patient's activity must be strictly limited. Gradually increase the activity level as the patient recovers fitness. Take care to monitor so that the patient does not over-exercise for energy expenditure.