Tips to gain kid's weight:
Consult doctor: Sometimes kids can be allergic to a particular food or milk. This food allergy can make it difficult for the body to absorb nutrition and proteins. Your doctor can advise what food is healthy for your child. For example, Celiac disease among kids leads to immediate weight loss. So, know the problem behind the underweight kid.
Include green vegetables: Vegetables are rich in nutrients, proteins, minerals which improves body growth and also keeps the kid healthy and fit. Green vegetables contains healthy vitamins which maintains eye sight and also improves concentration.
Zinc rich foods: Some kids have less appetite which makes them lose weight and look underweight. Lack of appetite among kids is also due to lack of zinc. Include zinc rich foods such as lamb, sesame seeds, watermelon seeds, peanuts, beans, spinach, mushrooms, asparagus and milk in your kids diet to make him/her gain weight.
Fruits and nuts: These are must have in a kid's diet. Give your underweight kid fresh fruits which are filling and nutritious. Grapes, apple, bananas, oranges and watermelon are healthy fruits for your kid. Nuts such as almonds, pistachios, peanuts, cashew nuts are rich in good cholesterol and calories which helps in the growth and weight gain of kids.
Include these foods in the kids diet to make him/her gain weight in a healthy way. Reduce the intake of foods which have artificial sweeteners as they fill the stomach easily and controls appetite.