Child will not eat and never hungry

My child is turning 2 this week and I am extremely concerned with his eating habits and weight. At one years of age he weighed 18 lbs and has been 20 lbs since he was 14 months. At meal time he will only eat about 5 bites of food and cry and whine to get down for his chair. I offer him food throughout the day, all day and he just doesnt eat. If I dont make him eat he just will not eat. He will go a whole day refusing to eat and doesnt seem to want to, its like he's never hungry. I am very concerned that he is not eating and not gaining weight. I have expressed my concern to his pediatrician but he doesnt act like its a concern. Is this something I should worry about?

[Renee Radenberg]

His weight is below the 5th percentile for his age. Suggest Pediasure, milkshakes or smoothies with fruit - milk or yogurt, banana or strawberries (or any type fruit), ice cream for all meals (in place of milk) for additional calories for weight gain. It is frustrating when they become more interested in their environment instead of eating. The most important thing is to RELAX. You do not want mealtimes to be a battle of the wits between the child and you. Do not force a child to eat and give them the foods they like. Slowly introduce new foods, and if he does not want it, do not make a fuss over it. Let it go and enjoy the meal. Try again in a few months. Sometimes it takes 5-9 times to introduce a food to a child that they will accept the new food. Hoped this helped you.