I go through the same thing.
My hubby works 7-3, and doesn't eat all day. Therefore, by dinner (5-ish) he is really hungry, but then around 10 he is hungry again. My thoughts is that our dinner is his lunch, and then at 10 he has a dinner
But at 10, he always offers me food... "you want one?" and of course sometimes I really do want to eat, just because it looks/smells good. But I'm really trying to say no. And sometimes when I saw "I don't want to eat just to eat, I'm really not hungry" then he'll say "yeah, me neither"....
Sometimes I just have to turn away, or eat something else. Luckily, the foods he snacks on are things I don't like.
I think every once in a while you should eat some of the fish n chips, and some pie... because if you don't, you will just crave it and then eat more. But eat it in moderation, and try to eat different "better" foods around your hubby and son.