In a walkable area, you don't buy for a week at a time, you buy what you need for a meal or two. Popping into the store is a pleasant, 10-minute diversion where you're likely to see friends and neighbors, not a 2-hour safari overland to the edge of nowhere. It means buying fresh, healthy food, rather than the giant pallets of highly-processed product that I see folks haul out of the CostCo.