not gaining weight

My 21 month old daughter weighs 18 1/2 lbs and is around 28 inches tall.  I'm having a very hard time getting her to gain weight.  She is a very picky eater, and has failure to thrive, so every meal its like im forcing her to eat.  I give her 2 cans of pediasure a day as added calories and she eats 3 meals and 2 snacks.  She does not like to eat, but I make sure she does because she can not afford to lose the weight. I just don't understand why she isnt gaining any weight.  She hasn't gained much weight since she has turned 1 and off of formula. She also has sensory issues to the mouth which i believe is a reason why she doesn't like food.  Please help me with how i can get her to gain weight.  

[Renee Radenberg]

Yes, her weight is below the 5th percentile for her age. You did not state what type of foods she is on, only she has sensory issues. Is she eating regular food or still on blended or soft foods? If she is only eating blended/soft foods she may need to learn how to chew and swallow. Some children just do not know how to do it and need to be taught. They need to learn how to chew and swallow food properly; it is not really an instinct behavior like sucking. Has she been evaluated on how to chew food? If not, then suggest getting her evaluated, by going to your MD, and start therapy so she can start to eat regular food. That’s good she is taking Pediasure. Suggest adding ice cream to the Pediasure for additional calories (like a milkshake) and increase to 3 cans a day to help with weight gain. If she continues not to gain weight, then recommend having her MD check her medically. Hoped this helped.