On short trips that start from home (rather than an airport), I take one days meals frozen. They act as ice for keeping other things (beer?) cold and when they thaw you can heat and eat.

My favourites are stews, but I suppose anything frozen will work.

BTW, I buy small amounts of condiments, OTC drugs, etc from Minimus so I don't have to carry a jar of mayo or a tin of extra virgin olive oil.

I buy as I go, but sometimes you can't always find a place to buy, so I also carry some freeze dried meals. I like the type that you add boiling water, stir and re-seal.

I carry one luxury item, a plunger coffee maker that is also a mug. I really love my coffee and I can't stand the usual sludge I find on tour.