DS8 is in the 85th percentile for height and the 10th percentile for weight. I suppose I could adopt the old "he'll eat when he gets hungry" philosophy, but I prefer NOT to be able to see every vein in his body through his skin!
I do not limit what I cook to only what he will eat, and I do encourage him to try everything at least once, but I will ALWAYS have food available that I know he will eat if he balks at what I am serving - California rolls, peanut butter and baked beans among other things.
I'm terrified that he doesn't get enough protein.
I have a dd5 who is in the same boat. She also spent the first two years of her life in and out of hospitals EVERY time she got sick....even with the common cold. Her immune system was so bad (dr. said due to the fact that she was tall, but way too skinny for her age). She stopped nursing entirely at 14 months (she didn't nurse that much anyway), only to discover that she didn't like milk. My pediatrician gave her chocolate milk in his office one day, and she drank it....so, he told me to give her chocolate milk if that is all she would drink. He also said she was not "allowed" to skip a meal.
Well, that TOTALLY started me in the cycle of "catering" to my child. So, yes...I do cater to her. However, we do have a rule that with every birthday there is a new food that she must eat. This year, she picked hamburgers as her food. She doesn't like them, but she will pick at it until it is gone.
As a mom, you can always tell which foods your child really doesn't like, compared to the ones they just don't want to learn to eat. For example, my dd says she doesn't like hamburgers, but will comment on how good the house smells when I am cooking it (before she knows what it is).

She grudgingly eats it. However, put corn in her mouth...and you might as well have put in poo!!! Sarah Bernhardt would have NOTHING on the dramatics of this kid!! I guess she really doesn't like corn...or watermelon...or many other yummy things that anyone in their right mind would love!!
However, there is not a SINGLE food that I was forced to eat as a child that I can even tolerate now....beef stew and grape juice were things I was forced to eat, and even now the smell makes me want to barf. In contrast, there were many foods I was not forced to eat as a child, and never would've eaten as a child that I truly LOVE now (guacamole and balsamic vinegar come to mind).
Bottom line, my dd is polite enough to know NOT to raise a stink if we go somewhere and she is served something she does not like....that's basic manners. But, in my heart I cannot/will not make our dinner time a battle of wills over food, when my dd has always had food issues. As long as she is getting enough protein and fruit (and taking her 15 vitamins a day

), I try really hard not to get too upset over her limited choices. We put good food in our house (almost entirely organics, raw milk, raw butter, and raw cheese), and if she chooses not to eat our dinner, I really have very little problem with her getting a few slices of cheese to eat instead. As long as she is choosing good foods....I don't care what she eats...as long as she actually eats!!