Laura from my own experience, I say to still just offer them the hot meal and if they don't eat it then they don't eat it. Their choice. Your job is to prepare the food and decide what it is, their choice is to put it in their mouths or not. This is the age where DH and I went really really really wrong and offered whatever it was DS would eat, saying it was because he was teething, etc etc etc, and I have regretted it every day since.
If they are eating sandwiches and bananas and such at other times in the day then you know they are getting food - breakfast, snack, lunch, snack and then if they don't want dinner then so be it. But still only offer them what you are making.