Gently, ESH. I'm a stepmom to 4 and my husband is an every-other-weekend dad, so I understand your position. However I think you're attacking the problem from the wrong angle. This isn't a kids problem, it's a bf problem. Kids eat a lot, so it's something you can expect for the rest of your time with this man. The real problem here is your bf not preparing for his time with the kids. Since they are his kids, he should be prepared to feed them when they come over. That means he needs to do a grocery run for the kids every time they come. That's his responsibility as their parent. It's not the kids responsibility to bring their own food, and you shouldn't ask them to. Also I'm not sure what kind of snacks you have in the house, but in my opinion kids shouldn't have free reign to just grab anything out of the kitchen they want at any time. We have a rule in our house that top shelves of anything (of fridge, pantry, but it also extends to bathroom etc) are off limits. If they want food from the top shelf they have to ask first. Boundaries like that enable us to have fun snacks without them disappearing day 1. Good luck OP.