I've been experimenting with OMAD using only shelf stable ingredients (because no fridge.) I throw in a cup of rice, some canned meat, dehydrated veggies, bouillon, honey, nut butter, cheese powder, spices... Cook it in my 12v oven for 2-4 hours. Pretty tasty and it does the trick for balanced nutrition. Cheap as fuck, probably amounts to a few bucks per entire day's calories. I used to also put in a can of beans or scoop of lentils, but that much fiber in one meal was *destroying* my gut.