>>326773
Depending on length of stay/need for leave-no-trace you can do various things.
If you are just out for a short time (1-3 days) you might just get some snacks as recommended and eat them. No heating required, but keep in mind to drink enough. Never eat without drinking, else you will dehydrate.
If you are out for longer (3-7+ days) you should think of packing some other stuff. You might mess your stomach up with extended consumption of snack bars (lel) and dried foods, also you will want to eat something warm probably.
Without a need to stay low key (stealth camping, summer season = forest fire, SHTFantasy) you can just make a nice camp fire and cook your stuff on there. Note, that you will start smelling like smoke, it's ridiculous how often people overlook that fact and act surprised.
If you gotta stay hidden or can't make an open fire (or don't want to), you can use a camping stove with any kind of material. Esbit, gas, alcohol, pick your poison. Very compact, not too much smell/smoke/flame and works fine. Gas in winter sucks, as you will need half a can to heat some medium sized pot, so stick to other fuel in winter.
Okay, so what to cook now? My receipt for long term food in the outdoors that is weight and cost efficient as well as doesn't mess up your stomach is a mix of dry rice and lentils packed in ziploc bags. It's a very efficient way to carry around foodstuffs (and other gear) that the UL fags first brought into practice. You can also take bannock and things like that to make bread or soup. Also bring tea, hot chocolate, soup powder and whatever else you might stir into a cup of hot water.
Basically for longer stays you want all the proteins, carbohydrates and fats you need, plus vitamins, minerals, etc. (that's macro- and micro-nutrients). Rice plus lentils gives you all essential amino acids and is very easy to cook, just throw it in your cup/pot with a 1:2 water ratio and let it cook with some stirring until the water is gone. Add some sauce/spices and you're set. Add some oil for fats and better flavor. That's the cheap way basically.
If you don't just hang around outside but actually do a lot of physical shit, use more fats and carbohydrates. I recommend dextrose sugar tabs, they don't hurt your teeth, go directly into the blood and really give you a nice supply of energy without that extreme energy curve other sugars do (super awake, then slacking off from low blood sugar). Also they're kinda cheap, you can buy that shit in bulk I think and just take a pouch full of them with you. Remember to drink when you eat them.
1/2