I can't find any good info on this just by googling. DS has his 3 yo WBV coming up (he turns 3 at the end of february), and I will talk to his doctor about it. DS hasn't gained any weight since his 2 yo visit... literally. He was 26 pounds at 2 yo, and he's still 26 pounds.
I get nervous about weight b/c he fell off his charts at 5 months, and by the time he was 17 mo old had only gained 4 pounds. Turned out, he had a massive hole in his heart and his heart was enlarged to 3 times it's normal size. He had open heart surgery when he was 19 mo, and between the surgery and his 2 yo visit, he gained 7-8 pounds. But then stopped gaining again. He is getting taller, so that's something at least.
As far as diet, he's kind of picky... and actually requests pb&j sandwich for nearly every meal... we don't give in to this of course, but a typical daily menu looks something like this:
pb&j for early breakfast
midmorning snack at daycare (I think this is usually cereal or crackers)
lunch at daycare includes a protein, veggie, fruit, and milk
afternoon snack at daycare (usually some kind of crackers and water)
protein, veg, starch, fruit, and milk for dinner
for proteins, we do a meat or cheese dish (he loves steak, chicken, pork chops)
starch is usually either WW pasta, or brown rice, sometimes potato
we give him whole milk, and try to limit juice (although we do not have a juice ban in our house so he does get it regularly, but not more than one small cup a day)
we also add butter, olive oil, or sour cream to a lot of our dishes
we allow him to drink water/milk on demand.
I just stopped BFing about a month ago.
He doesn't like avocado, yogurt, nuts (except in the form of nut butter) or smoothies.
He has plenty of energy, although he is a terrible sleeper, and does have purple circles under his eyes. He is smart, talkative, creative, sweet, very loving, and just generally pretty easy going (although he definitely has his moments).