actually imo, i feel that though the pediatrician is a professional, but taking care of a kid needs to be hands on.
even they have the knowledge from all the books, they dont face your child 24/7 so you know their condition best.
so if you feel that he is really eating too little, then just go ahead.
maybe just let him snack thruout the day.
if he likes certain food, offer it more to him.