Desert Survivalist

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

Food regeneration explained
If consuming the food will cause your HP to be > 100%, then you only get points for the difference. For example, if you have 200 health, and your max health is 250, consuming anything that grants more than 50 HP will be wasted, as you'll only gain 50 points towards the award.

This also means that you can't "over-heal" with something that grants more HP than you currently have with the intention of adding more points towards this achievement. For example, a Wasteland Omelet grants +6/(60sec), or 360 HP total. If your current HP is 100 with a max of 250, consuming the omelet will only grant 150 points towards the achievement. If you take 50 points of damage while the omelet is healing you, common sense says this should give you an extra 50 points, but this is incorrect. You still only receive the 150 initially granted.

One other thing to note, there seems to be a limit (4---a limitation of the Gamebryo engine dating back to Morrowind) to the amount of unique things that you can eat at once that actually take effect. After hitting that limit, you no longer gain stat adjustments/rads/FOD/points towards Desert Survivalist. If this occurs, simply wait until some of the food items "wear off," then continue consuming.

A good option is to travel to New Vegas Steel, just opposite Vault 3. Inside are several molten steel girders dealing around 35 damage regardless of DAM threshold. This can be constantly used and has no effect on apparel or limbs. Another (perhaps more common method) is to go to any body of water and stay under water until you at the brink of death. Then eat the food you have, allow yourself to heal and repeat.

In hardcore mode, it is extremely easy to get this challenge: Get enough food to heal 10000 HP, lose enough health which leaves room for the most healing food to exhaust all it's healing, then eat all food at once.

Locations for obtaining food, en masse

 * William Farber inside the Terminal Building at Camp McCarran stocks a large amount of vegetables.
 * 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.
 * 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 have a wide variety of food.
 * The Ultra-Luxe sells Wasteland omelet. Resupplied every Sunday and Wednesday. Also, there are fresh vegetables and meat in the basement, but this requires stealing them.
 * Kill a bunch of Giant radscorpion in The Thorn or Scorpion Gulch, get a total of 150-200 Radscorpion poison gland, and bring them to Ruby Nash in Primm and tell her to make some of her famous casserole.
 * You can also get unlimited number of foods from Sierra Madre vending machine at Abandoned Brotherhood of Steel bunker, if you have Dead Money add-on.
 * 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 (50+).