help for my son to gain weight?

My son is 16 months old and is at the 3rd percentile for his weight and 7 for his height. Also, he is allergic to milk and other dairy products. He is not lactose intolerant, he just cant have dairy at all. What are some things i can do to make him gain weight?

[Renee Radenberg]

His weight is on the 5th percentile for his age. Suggest making ‘milkshakes out of soy ice cream and soy milk blended together or soy smoothies (soy yogurt, soy milk and frozen fruit). All soy products are milk free because they come from plant and not animal source, however, he will get additional calories and protein for weight gain. Use chocolate or vanilla favored soy products so there is not so much 'soy' favor and it will taste like a real milkshake / smoothies. If you do not want to use soy milk, then use Pediasure which is a dense nutrient drink. Have him eat extra foods to increase protein and calories – meats, fruits, vegetables, and grains. Hoped this helped you.