Our 2023 average monthly grocery purchases for a family of 7 (granted kids are younger; oldest is 11) was $560. That is everything we would purchase at a grocery store: food, cleaning supplies, toilet paper, etc.

We don't buy a lot of prepared foods. We buy fresh fruits and vegetables and other ingredients and make most of what we eat ourselves. Also don't eat a ton of meat. Not vegetarian, but my wife is "Word of Wisdom-etarian" if you will, so we eat meat sparingly (few times a week) because I don't care enough to separately cook meat for most meals.

The correlary observation to the grocery budget is garbage going out. We take our one black garbage can out once every other week, if that. Sometimes skip a couple weeks. Our neighbors have 4 cans that are overflowing and taken out every week. Maybe that's just anecdotal, though.