Hi There,
My 20 month old is a great breakfast eater and eats a good lunch... some dinners he does great, others, he doesn't eat much. Toddlers generally eat better at some meals than others... my son eats most of his food early in the day, my niece who is the same age eats barely a few cheerios for breakfast, and more at her other meals. We try to eat dinner as a family and I generally make one meal for everyone (with a few exceptions), I serve a little of everything, and he eats what he eats... sometimes he will eat just one part of the meal, but usually finds something he likes. My son still isn't much of a veggie eater, but will still eat baby food veggies, so on most nights I give him that as well, just to assure he is getting some veggies. Also, sometimes kids won't touch things you think they will like (mine won't eat chicken nuggets) and love things you don't expect (he loves refried beans on tortilla's like a little taco with a little taco meat). So, just offer him a variety of what you are eating and don't make him the same old things he likes... you are not a short order cook, and kids will not starve themselves... if he is hungry he will find something from the dinner plate that he likes.