If you are concerned that your child may be underweight, consult your child’s physician. Assuming your child has no underlying medical concerns, the idea will then be to encourage weight gain in a healthful way, with food. Empty calories from foods high in fat and added sugars might add a few pounds, but they will not provide the nutrients a child needs to build strong bones and a healthy body.
If your child is underweight, start by ensuring that most meals and snacks are nutrient-rich. Good sources of protein for weight gain include eggs, peanut butter and other nut butters, bean soups, hummus and full-fat milk, yogurt and cheese. Whole wheat bread and pasta, mashed potatoes and hot cereal are excellent carbohydrate choices, while nuts and seeds, and avocados, are healthy fat sources to help your child gain weight.