A child who is thin can gain weight on dietary changes. The diet should be high in protein, nutrients and vitamins. Especially children who are developing will need more supplementation. It is also important to rule out whether your child has a digestive disorder or hypothyroidism that is causing him or her to be thin. There are many reasons why a child may be thin, including family genetics and insufficient dietary intake of nutrients. Especially children who are developing, consume a lot and need to consume more energy and nutrients or more. Diet should maintain a balanced intake and not picky about food. Eat a diet high in protein, nutrients and vitamins. If it runs in the family, it usually does not require special treatment as long as it does not affect health. If your child is thin, you should also wonder if it is caused by a digestive disease or hypothyroidism. If the child is thin and accompanied by bloating, constipation, diarrhea, fatigue and other abnormal symptoms, patients are advised to go to the hospital in time.