I find the buying food for your adult kids kind of weird. If I am going to their house for dinner I will buy wine, dessert etc but I don't grocery shop and buy them stuff. Sometimes my kids will pop over with a great bakery danish and we will all share it.
My mom is huge on bringing us food, making us food, and bringing lots of stuff. I have this imaginary conversation in my head with her where we are saying the exact same phrase but with opposite interpretations. So a statement like 'I have one white shirt' which for me is awesome, perfect, I am ready for anything. In my mom's perspective there is lack and scarcity and a real need to shop because it is ONE white shirt. It keeps me sane and crazy at the same time to think of that.
My brother has been putting his foot down with the food. His family does not eat very many sweets so the regular cookies were being thrown away. He just started telling her not to send/bring them so often but if there is something they would like he will tell her and she makes it. He has been working on this for 5 years. I take all the cookies but adjusted so we don't get the kind I hate anymore. I throw some away. There is no way I can put a dent in her driving out crockpots of food including bacon or ham, I haven't eaten pork products for 37 years. So the kids eat some, then what does not get eaten gets tossed. I know where I stand on that one, but truly it feels like a passive aggressive dig to keep bringing out this particular food (so they are not 'deprived'). I don't think this has anything to do with age.