Underweight 29 month old girl

My daughter is 29 months old and weighs 22lbs, 36 inches tall and 17-inch head circumference. I have been concern about her weight because she eats very well but does not gain weight. The doctors have assured me that she probably has a very high metabolism but she has been this weight for about a year she does not lose weight it just stays the same what can be the cause of this?

[Renee Radenberg]

Her weight is below the 5th percentile and her height is between the 50-75th percentile for her age. Suggest giving her nutrient dense drinks in place of milk for all meals and snacks, such as milkshakes (milk, ice cream, and fruit blended) or Pediasure. She needs protein sources at each meal such as the milk, puddings, rice and bean combo, meat, to name a few, to help gain weight. At this age she can also be eating finger foods so let her eat on her own. Some tips for additional calories: If she likes pasta, then add meat or cheese sauces to the pasta instead of plain tomato sauce or plain pasta. Add dry milk to oatmeal, mashed potatoes, gravies, creamed vegetables, and creamed soups (add additional protein sources to soups such as meat). Use all fat dairy products and no low fat foods so she has the calories she needs. Hoped this helped you.