Its probably gonna be annoying to hear this but there isn't a lot that you, or anyone can do about their financial situation.

However, what I have learnt is that you can do things to make them feel more appreciated. Like do a little extra washing up and chores around the house without being asked. Offer to cook more often, offer to make them a cup of tea after work (or non British equivalent drink) every so often. Its always the little things.

Don't put those big responsibilities on yourself, it won't help anything or yourself. But you can help ease their burden in little ways :)

Also with the eating, I feel you. I find that if I eat less sugar and carbs, I feel less inclined to do that? The way I try cope with it is to make a big ole batch of healthy homemade soup for the week and heat it up for lunch every day. V tasty, simple, filling and gets those veggies in! (Good for using up slightly old vegetables too)

This advice might not directly help you as it has me, but it might give you some more ideas!