Depends on how long you think you would need to be away from a real kitchen with ingredients?
If it was just a handful of days and I had the money, I would get some MRE type meals, because they have the heat source to cook it with integrated into the kit, lugging about some type of hobo stove or something could be a bother, especially if you have no experience using it.
If you were going to be heading into the wild (regardless if urban or forest kind of wild) for a while, like weeks, then I'd get some type of portable kitchen unit that runs on some heat source that is both inexpensive and not too weighty, like maybe the gel type fuel (think its called FireDragon? same company makes lightweight portable stoves to burn it in). And then a large suitable container for water (need to be enough both for drinking and cooking liquids), and then some spices, some red lentils (cooks fast enough for portable stoves) and whatever else you could put in lentil stew that stores easily during travel circumstances. E.g. rice, spices, millets, oats (nice to cook on its own to change up things, just lentils gets boring).
That should be a very efficient way to survive, a weeks worth of food couldnt cost more than 10 bucks, if you dont account for the price of the spices. Fuel and the portable kitchen thing shouldnt be more than something like 10-20 bucks max either, if you're buying it at a store with sane prices.