I get by with a lot less and I am often in remote areas where I might need to go 2-3 weeks without a grocery store stop. My 4 cu ft refrigerator/freezer will store plenty of meat and other perishables. I do cheat on the fruits and vegetables. In hot weather they need some cooling so I use a small folding cloth ice chest. I put in a frozen blue ice packet every few days.
Rather than getting a unit big enough to handle weeks and weeks or months of food, I also have a lot of menus that can use non-refrigerated items. I make some pretty decent tacos and other dishes with Costco canned chicken.