Food weight is roughly indicative of how much you're going to eat, and it's what most grocery stores list nowadays on the shelf price labels, both for basic foo

Food weight is roughly indicative of how much you're going to eat, and it's what most grocery stores list nowadays on the shelf price labels, both for basic foods and processed/packaged. As far as spoilage goes, that's just purchasing what you'll assume to eat. And having a few vegetables go off at the end after you've already eaten many of them doesn't even double the price per unit, while convenience food ranges tend to be many times the price.