I'm thinking about this same issue so hopefully this takes off. One idea that I might consider is that people often waste food for a variety of reasons associated with care and high expectations of themselves. On the first issue, I've been to a couple of conferences where ethnographic methods were used to reveal that food waste in the home was stemming from an overwhelming concern that the homemaker would not be able to provide for people if they happened to come by, or if their kids friends came over, or an impromptu dinner party happened. I'm not sure how to manage that, but it could be used as a leverage point to make people feel better about how their not wasting is a form of care for others. Second, at least in my anecdotal experience, food waste comes about due to this notion that "of course I'm going to cook a meal every day because that is what I am supposed to do." You could make this a social engagement for promoting points for any members that can offer recipes to others that a) request help or b) have their food getting close to spoilage. A second subset of options could be on how to preserve foods easily to extend shelf life, e.g. quick pickling is stupid easy and could be put in as a pop up option as spoilage gets close.