hello, according to your situation, your calorie intake is low, and you are in the growth period, which leads to malnutrition and thin body.

According to the daily intake of China Nutrition Society, you can compare it yourself:

Millet: 251-411g

Vegetable: 311-511g

Fruit: 211-411g

Meat birds: 51-75g

Eggs: 25-511g. Porridge+meat bag+egg+fruit; Soymilk+meat buns+eggs+fruit

fried rice with eggs+soy milk+fruit

For Chinese food at school, you can choose protein-high foods such as meat, pork liver, fish, tofu and dried tofu

Make a dish for dinner: steamed fish, stewed pork ribs with potatoes, fried pork liver with sweet peppers, fried beef with celery and fried lean meat with your favorite vegetables, stewed chicken with wax gourd and so on.