How to help my teen son?

My son can not stop eating. He has been sneaking food since he was tall enough to reach the countertops and we would find banana peels hidden in his room. Now he’s 15 and is still sneaking food and just keeping the trash or dishes in his room. He comes home from school and eats any leftovers or anything he can find in the kitchen, then he has a full dinner. Later after I’ve gone to bed, he’ll come to the kitchen and get anything else he can find and even search for things that may have been hidden.

This morning I discovered there’s a full can of whipped cream missing (that I had hidden in a drawer under other things). I have been keeping most individual wrapped things in my room so he won’t get them, but that doesn’t always stop him and I can’t keep refrigerated things in there. He will drink 4-6 sodas at a time (they only recently started drinking it and we only ever have diet), a whole bag of chips or crackers, just large quantities of food. When we eat dinner, he absolutely inhales it and may not even wait for it to cool off!

I have two younger children as well so it’s not possible to just not have food here, but I’m lost on this! I’ve tried to discuss with him but he won’t have it and absolutely shuts down. He has ADHD and was on Vyvanse, but stopped taking it, and when I brought it up he absolutely refused to reconsider.

There has never been food insecurity in our house, so it’s not that. What can I do?!