Desert Survivalist

Desert Survivalist is an achievement in Fallout: New Vegas which is awarded for successfully healing 10,000 points of damage using food.

Food Regeneration Points
The game tracks the amount of health the Courier heals through consuming food as a general stat. However the number of regeneration points are not determined by the number of Hit Points the player heals with food, but rather the number of points a food item (that the player consumes while hurt) can heal. This means that if the player is hurt by X amount of points, and consumes an item that heals Y amount of points overall, the game will add Y food regeneration points to the player's statistics even if Y > X, which count towards the achievement/trophy.

So a player who is even hurt by 1 point, and consumes a bottle of purified water, which heals by 6 points for 5 seconds (therefore 30 points overall), 30 points will be added to the player's "Health from Food" stat. This logic applies for the majority of food items, though some do not add their total health regeneration points to the statistic.

This method of tracking can also be stacked if the player consumes all the food items of his choice at once without leaving his Pip-Boy. However it should be noted that if they are healed completely by the instantaneous healing of the food items they consume, the "Health from Food" stat will cease tracking the rest of the food.

With this knowledge, it is therefore possible for a player who has never been healed by food before to get the achievement/trophy in 1 go without leaving his/her Pip-Boy by being hurt by roughly 21 points (in order to offset the instantaneous healing¹) and consuming 334 bottles of purified water.

¹ Purified water, when consumed, seems to instantly heal between 1/16-1/17 points of health (though this can vary when initially hurt).

Locations for obtaining food, en masse

 * William Farber inside the terminal building at Camp McCarran stocks a large amount of vegetables and he restocks every 72 hours.
 * Make your way from Ruby Hill Mine to Jacobstown. You can encounter a lot of bighorner bulls. Each will often contain 3 to 5 Bighorner meat that restores 30HP (depending on your Survival skill).
 * Etienne at the Westside Co-op stocks a large amount of vegetables and other food.
 * You can find lots of malnourished bighorner and malnourished brahmin at Matthews Animal Husbandry Farm that won't attack you.
 * Genaro sells a variety of suspect meats inside Freeside's North Gate.
 * In the refrigerator inside the McBride house there are 10 brahmin steaks. It requires you to steal them unless you have completed The Screams of Brahmin.
 * If you have the Followers Safehouse, you can get as much food as you need. The Followers of the Apocalypse doctor restocks the fridge while she's there, and as long as she's in the safehouse, the fridge is immediately restocked as you take from it.
 * The Presidential Suite in the Tops Casino is stocked with fresh fruit.
 * The Boomer Chef in the Mess Hall & Munitions Storage at Nellis Air Force Base usually has a wide variety of food.
 * The Ultra-Luxe sells wasteland omelets. They are resupplied every Sunday and Wednesday. Also, there are fresh vegetables and meat in the basement, but this requires stealing them.
 * Kill giant radscorpions in The Thorn or Scorpion Gulch for Radscorpion poison glands. Bring them to Ruby Nash in Primm and tell her to make some of her famous casserole.
 * You can also get an unlimited amount of food from the Sierra Madre vending machine in exchange for Sierra Madre chips in the Abandoned Brotherhood of Steel bunker.
 * There is also lots of food in the refrigerators in the Vault 3 cafeteria behind a locked door.
 * In caves around Zion Canyon you encounter large amounts of cave fungus.
 * The sink in The Sink can be upgraded to create purified water from empty bottles. Getting a few hundred empty bottles is quite easy by visiting the Sunset Sarsaparilla Headquarters and looting the boxes of empty bottles.