well if mine say they dont like it they go hungry!
they are both good eaters... and generally i give them foods that i KNOW they like, and when offering new things have things they like as well.
TBH at the moment both my 2 tell me they dont like it nearly every meal, drives me mad!, but i KNOW they like it and i simply reply "well then you will be VERY hungry at bed time / tea time or whatever!" they always sit odwn and eat it.
IMO food is food. It all tastes nice enough!
Mine also know alot about nutrition (as much as a 3 and 5 year odl can understand!) they know that at EVERY meal we have protein to make us grow. Veg for vitamins to keep us healthy and carbohydrate to give us energy!
They also know about certain foods eg
Milk / yogurt / cheese etc = calcium. STRONG bones
Green veg and meat = iron = healthy blood
salmon = omega 3 = healthy brain
fruit and tomatoes = vit C to help stop colds
carrots = see in the dark
Generally a light hearted converstaion about what they are eating and how it is good for them makes them eat it! and if not they go hungry! (the reality is the VERY rarely dont eat it tho!.... which im sure is becuase they know there is nothing else!