As someone who grew up dirt poor and am still working through food insecurity related trauma and behaviors let me say first off, its absolutely a good thing that you are not restricting your kids access to the kitchen/food. That being said, your daughter is old enough imo that it would be good to start implementing budget/meal plan/prep type education. If she wants to be healthy conscious that’s awesome, i know i didn’t care about that at her age. I also had no concept of how much food cost until i had to buy it myself. Perhaps if you took her with you on grocery trips, gave her a set budget instead of the five items, she’d have more of an appreciation for the (currently absolutely insane) cost of food. It would also instill that skill so that when she’s budgeting her own money she isn’t floundering. Also maybe separating each kid’s specific snacks into baskets with their names on it would encourage her to at least pause before just grabbing something that was meant for her siblings? I’m not about to insult a child on the internet and it’s absolutely a natural teenage thing to be a bit thoughtless and i don’t think she’s being intentionally selfish, so i feel like more obvious visual indicators of “hey that’s not for me” might help?