I wouldn't hide the crisps etc. If they eat them all then they learn that they don't get any more until the next food shop and they have to wait.
We focus a lot on ingredients rather than instant snack food. So always things like flour, eggs and oats in the cupboard, tins of soup, crackers, a loaf of bread in the freezer, bags of frozen vegetables and fruit.
We buy a lot of fruit that lasts ages when kept in the fridge e.g. apples and pears.
If DDs eat all of the crisps then they can have a slice of toast or some crackers and butter with a piece of fruit for a snack. I'm not buying them more just because they've been greedy and eaten it all in a few days. I think it's a lesson they need to learn about regulation and portioning rather than there being an endless supply.
If they eat all the cereal then I can still make porridge or an omelette for breakfast.
Maybe swap to big pots of plain yoghurt rather than small tubs of flavoured ones.
We do one shop a week. It does mean by the end of the week we are eating more out of the freezer and cupboard but that's fine. A lot of frozen veg is excellent, we always have pasta in the cupboard, I buy meat on reduced stickers and put it straight in the freezer. So nobody is going to go hungry.