I have jsut been reading a chapter on this in The Mighty Toddler.

It says something about trying not to always substitute with milk as thats what they want and he will just learn that if he doesnt eat dinner he will get a nice big bottle of his favourite drink. Dont know how true that is but it kind of makes sense.

It also says that toddlers will eat if they are hungry and it is common for them to have one big meal every one or two days and then basically just snacks at other times. It is a passing phase and as long as you are offering a variety of nutritional things as well then that is good.

HTH. Just what I was reading at that very moment. Havent got to that stage myself yet though