We usually eat out about 2x a week. I have a family though (husband, 2 kids). When I was single, I ate out for at least one meal most days. Some days I ate out for every meal, plus drinks. It was as different lifestyle. I was home much less and out with friends a lot more. I tried not to waste food though. Leftover pizza from one night got paired with a salad I made from stuff I bought at the grocery store and eaten for lunch later in the week. Veggies about to go bad got roasted and eaten as part of dinner.
OP, you need to rethink your habits. There's no reason you need to buy groceries you're just going to throw away. Also, why don't you eat your restaurant leftovers. Also, there is a food box in my neighborhood where you can donate non-perishable food. I'm sure there's one near you.