Your husband is totally selfish, if he can't see it, continue to tell him/show him everyday until he changes his behaviour.
We might have baked cookies, we just ask if we can have one. You don't help yourself to anything you want, because you paid for it. That's what a narcissist does.
If I cooked 3 sausages, 2 bacon for 4 of us to eat and husband eats 1 rasher , 1 sausage half an hour before plating, he would get 1 slice of bacon and 2 sausages. I certainly wouldn't deprive myself or children their allocation of food, because he helped himself. He's helped himself to his allocation, so of course he gets less when it's time to eat.
There's always one last chocolate bar, one last banana and anyone who want's it, will ask if they can have it. Daughter has her own chocolate, husband will ask if he can have some, daughter replies yes or no. If NO, he can't have it. It's hers ! Yes he pays for the shopping, no that does not give him carte blanche to eat everybody's food, treats, snacks.
What an ignorant, horrible shit of a husband you live with. What does your child do, when their dad has eaten their prepared lunch? not eat? Some idiot posters are arguing with other posters saying he has no control/food addiction. WHERE IN THE OP DOES IT SAY THAT??
OP you have already questioned his behavior, he's already replied that he's paid for it and doesn't need permission.
Start with STATING, if he eats some of his food before plating, he WILL have less on his plate and TELLING him NOT to eat his children's treats, before asking. If he continues, bake earlier before he gets home and hide. Eat all of his favourite food/snacks ( cause I'll be surprised if he doesn't have his own favorites in the cupboard )
You are enabling him to do what he wants and ignoring obvious resentment your children will have as a consequence.
This will honestly affect your children more than you know it.
I would be so evidently cross and as frightening as a mad banshee, if he did this, he would NEVER do it again.