Hi J.,
It sounds like you have a little boy with a big appetite. My oldest daughter used to do the same thing your son is doing. When I would be tending to my younger daughter, she would go into the pantry and find things to munch on. I didn't tell her she was stealing. What I told her was that she wasn't allowed to get food without Mommy's permission.
I would feed her three solid meals a day, plus at least one snack in the morning and one in the afternoon most days. But she would still say that she was hungry. What I noticed was that the more she munched throughout the day on little items, the less she wanted to eat during the main meals, and it seemed like she was constantly eating, eating, eating.
When she was about three or four, we put a child-proof handle on the pantry so she couldn't get in there. Then she went for the refrigerator! So we put one on there, too. I kept stressing to her that she needed to eat lots of healthy food at breakfast, lunch and dinner, then she wouldn't want to eat so much the rest of the time.
When the childproof locks were on the refrig/pantry she didn't like it. She started coming to me several times each morning and afternoon for a snack. I had to keep telling her that one snack between meals was enough. If she truly seemed hungry because she had been extra active, I would give her a second snack in the a.m. or p.m.
There is not reason why three square meals and two, maybe three snacks a day aren't enough for a four year old. They often act like they're hungry out of boredom or because they like getting attention from us.
What ended up working out finally for us was: making her snack time at a specific time each day (she likes routine) and: making sure that she was really getting enough to eat at her main meals, then giving her a higher protein or high fiber snack. What I call a snack might be some peanut butter on whole wheat crackers, some cheese cubes, some cut-up apples with peanut butter or caramel, or some rolled up turkey slices. I also would have her drink a lot of water with that snack, because many times they are not getting enough fluid and that makes them think they are hungry. Eventually we were able to take the locks off and she stopped sneaking into the pantry, because she knew what time her snacktime was and would begin to look forward to it.
She still acts hungry at times outside of snacks and meals, but at this point, I can almost tell if her hunger is from boredom or stress and deal with that issue.
One other thing - I let my children have water or skim milk whenever they wish and don't count the milk as a snack. If they are truly hungry, the skim milk will take the edge off the hunger.
Prayer is always good, but try to make sure that he doesn't equate wanting to eat with being a bad person. Make sure he knows that you are praying with him to be obedient to you just like God wants us to be obedient to Him. It sounds like he might not totally understand what he is doing, but he seems so hungry when he does it.
One more thing (I'm sorry this is so long): why is he so hungry? People get hungry for so many reasons. Have you had his blood sugar checked? If it is off, it can cause constant hunger. He might have some other medical issue. And like I said before, he might be doing it out of boredom. Maybe he needs to be doing more stimulating things to get his mind off food? I have dealt with this issue with myself and my daughter, so my heart is with you.
Blessings,
S.