Actually, I'm going to encourage you to be compassionate in this case and realize that he is acting out of either compulsion or actual need, and not in a malicious way.
I suggest that you, in an effort to better yourself and the world, start bringing in special treats just for him.
Now, you don't need to take credit for this, the inner joy of giving should be reward enough.
Does he like sea food? Personally I love crab cakes, and I'll bet he does too.
The problem is that everyone else does too, so you should probably hide it in his desk somewhere so nobody else eats it. I'd think somewhere in the back of a bottom drawer, just to be safe.
If it's still there on Monday just pop it in the fridge where it's easier to find.
A really fun surprise is to leave some sushi in his car for after work, but it's hard to sneak out early to buy it without him noticing. So I recommend picking it up in the morning on the way in, it's just alot more convenient. Most gas stations have sushi now so it shouldn't be too inconvenient.
Again, I merely ask that you put yourself in his shoes and ask yourself what you'd do if you were a self entitled cunt with no sense of propriety?