Sounds to me you are a lot like me.. I used to get shoppers guilt big time before we all got really into this WOL.
I used to think I was terrible that I wouldn't buy just one little HC item for him to enjoy as a reward for doing so well.
I started thinking about it and realized rewarding with HC food was doing him an actual disservice, it was giving him double meanings and keeping him from seeing that this is a long term commitment.
My son is always starving after school ( the days he buys), and I think you hit the nail on the head when you mentioned he must have had a HC lunch in school. Maybe you should try sending him with his lunch a few days a week, and see if he comes home as famished as he does when he eats the school food.
My son takes boiled eggs, celery, carrot sticks, cheese and some pepperoni the days he brings his lunch. The days he does this, he is not looking in the fridge the minute he gets in the door.
I too grew up with having to have a bedtime snack, and I in turn started doing it with my son. We have adjusted our schedule to where we eat dinner about 2 hours before his bedtime. He still looks to having a snack before bed, and we sometimes have a big hissy fit or tantrum, but I do win out lol, I have learned I am the mom, and he is the child. Standing firm has taken a long time for me to develop, but I know that I am doing the right thing.
You may want to try what I did, which was taking him shopping and let him pick out the LC foods he would like to be eating. He may pout a bit when you stay clear of the chips and sweets, but after awhile it is such a high to see them picking the cheese and meats that are LC. My son now reads labels with me and will point out to me if something has more then 1 gram of carb per serving!
I also told him, if he feels he is not getting enough to eat, then we can go back to him counting calories, fats etc and be eating half or less then what he is eating now.
Being "hungry" all the time this is not what he wants to do, he wants to be able to snack and not have to be limited on portions.
George has been in a growth spurt on and off for the past year, and being a bottomless pit goes with the territory.. You just have to help him decide what it is that he wants to put in the pit lol!!!
Hope this helps a bit.
Have a great day
Laurie