First: Is the doctor worried?
Second: All kids are different - even in the family.
Third: I would focus on giving your child a well-balanced, healthy diet of fruits, veggies, grains, etc. Think of the pyramid. Or, contact a nutritionist.
If you pursue a high-calorie diet, you could end up on the other side of the scale and also have a child with bad eating habits later in life.
Updated
First: Is the doctor worried?
Second: All kids are different - even in the family.
Third: I would focus on giving your child a well-balanced, healthy diet of fruits, veggies, grains, etc. Think of the pyramid. Or, contact a nutritionist.
I do recommend having him further tested by an internist for any issues, to be safe.
If you pursue a high-calorie diet, you could end up on the other side of the scale and also have a child with bad eating habits later in life.