Eat less and eat more, but don't increase the amount of food per meal. Because most thin people have weak gastrointestinal function, eating too much at a meal often cannot be effectively absorbed, but it will increase the burden on the stomach and cause indigestion. You can change the number of meals per day to 4~5 times. Food is based on the principle of high digestibility, high protein and high calorie, and gradually increases the intake of various nutrients, such as chicken, fish fillets, vegetables, sea cucumbers, butter and cream. Eat whatever you want to promote appetite. At the beginning of the "fattening" plan, you can choose some delicious food you want to eat to stimulate your long-term tired appetite. It is suggested to buy some special recipes with beautiful pictures and cook all kinds of delicious food in various ways.