I have a Trader Joe's adjacent to my office. So most of the time I'll go down there on Monday and stock up on supplies for the week. I do the same with coffee. We have a local coffee joint (Collectivo if you're local to WI) and every two weeks I'll buy a pound and have it ground for my French Press and that's my morning coffee.

I do, at times, bring leftovers, packed in a plastic bag to keep separate from my clothes.