Wilderness Starving: Living Off Your Fat

3 months in the wilderness out of 6

How much fat would you need to survive in a long term situation?

I started seriously thinking about this after watching the show Alone season 3 in which the contestants strive to be the last one to stay in the wilderness for half a million dollars.

The winner stayed 87 days because the other remaining person was pulled out by the medics for losing too much weight (dropping below a BMI of 17). Zachary Fowler caught about 58 fish, one bird, and a handful of grubs in those 87 days.

That amounts to about 23,000 – 35,000 calories or ∼350 kcal per day (usd.gov).

A 25 y/o male that weighs 165 lbs and is 5′ 10″ tall would need to eat ∼2,750 calories per day to maintain his weight.

The food he gathered would maintain his weight for 8 – 12 days only, his fat provided the rest.

How fat should I be to survive 4 months eating 350 kcal per day?


Overweight but not obese!

I would have to weigh 200 lbs and would end up weighing 118 lbs with a BMI of 17 after 120 days.

I would need 35 lbs of extra fat.

Both the weight loss rate and energy needs change over time:

How many days would I last if I started with my current weight?

Only 2 months. Still that is much more than the 3 weeks rule of thumb that most survivalists memorize (rule of threes).


Where does that energy come from?

A sedentary 155 lbs man has ∼33 lbs of fat and ∼13 lbs of muscle as emergency energy source (Wilderness Medicine).

That is∼140,000 calories from fat and∼24,000 calories from muscle.

Those 164,000 calories could sustain you up to 2 months if you managed to get water, vitamins and minerals from the wild.

This is the reason why almost everyone can survive 3 weeks without food. And that’s why anyone can claim to be a survival expert without actually being able to thrive in the wilderness.

The 4 month threshold is what separates the survivalists from the hunter-gatherers.


Which nutrients would you need to survive?


You should always be well hydrated in a long term survival situation. Water is the most important nutrient.

Getting micro nutrients is relatively easy: although most edible plants relatively low energy, they do contain a good amount of minerals and vitamins.

Vitamin C

Is an important nutrient, and it is very abundant. Pine needles, juniper, berries, and plants in general contain lots of it.


Is another essential micro nutrient. It is not easy to find except in coastal areas. Some plants and their roots are a good source of it. Animals (particularly blood) are another potential source.


Is the most common deficiency in the world. Red meat (specially liver), seafood, birds, and insects are a good source of iron from the wild. Another good option is to cook in a cast iron skillet, for it increases the iron content of your food.

after three months living in the wilderness, taken from our camp

Month 3 of 6 in the Wild.

After my partner and I returned from our six months in the wild, she had a blood test done. Even though we were at a “normal” weight and had eaten relatively enough food: she had an iron deficiency. I encourage you to check my post How starvation affects survival to learn more about its effects.

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6 Comments on "Wilderness Starving: Living Off Your Fat"

  1. billrussell | July 15, 2017 at 01:15 | Reply

    155 lbs is a very small man, actually. Most US men are more like 200 lbs, but if you’re doing anything but lay around in your sleeping bag/tent, your energy needs, as a200 lber, are more likely to be 4000-5000 calories per day (in the wind, cold, wet). Mike Phelps had to eat 12,000 calories per day. You wont be in a swimming pool, but you’ll be working 3x as long per day, so, think about that.

  2. billrussell | July 15, 2017 at 01:18 | Reply

    Fowler lost 70 lbs in 87 days and the number of fish is irrelevant. What matters is the total weight of fish he ate. 60 fish could be just a very few lbs of flesh. Or it could be a ton, depending upon the size of each fish. Since he went 3000 calories in the hole, every day, and fish provide only 400 calories per lb (live weight) he should have been catching 8 lbs more fish every day, which might well have meant 20 fish per day. That makes his 60 fish look a little silly, does it not?

  3. billrussell | July 15, 2017 at 01:29 | Reply

    if those folks knew anything, they’d take a PARACORD Hammock and PARACORD gillnet, unravel them into their 3000 ft length, and weave 2000 sq ft of 3″ mesh netting out of the inner strands. Thats enough to close off a small cove (after baiting heavily with fish guts) and trap 100’s of lbs of fish. Using poles driven down into the mud, you can move the net and fish into a deep hole, near the bank, and keep them penned up there. This lets you dipnet or spear the fish as you need them, say, 15 minutes per day. It also lets you roll the rest of your big net around a log, and tie it down, protecting it from floating debris and storms.

  4. billrussell | July 15, 2017 at 01:32 | Reply

    It is legal for the Alone guys to bait in bears and arrow them from a tree platform. Boil off seawater for a few days, so that you’ll have the many lbs of salt needed to smoke/dry that fatty meat. That 100 lbs of salted bear meat will win the show for you! Another reason to take one of Chief Aj’s slingbows and the 6 arrows, is gained by having 4 of those arrows have 4 long, barbed tines on each fishing head. Those tines can be readily converted into 2 fishooks per tine. Set them on small log rafts, baited for ducks and gulls, with a drowning rock tied about a foot from each hook.

  5. billrussell | July 15, 2017 at 01:35 | Reply

    fish and game provide ZERO carbs. About the only carb sources available on Vancouver, in late fall are cambium, lichen and kelp. Kelp have only 50 calories per POUND. you can’t even begin to eat enough kelp to fulfill your brain’s need of carbs. So you have to make a stone or wood mortar and pestle and juice about 20 lbs of kelp per day. If you go at this right, a skinny person CAN win the (clear) 1/4 million dollars in 2 months. That’s $4000 per DAY, even while you sleep. You have to soak the seaweed in freshwater for a bit, so that you dont dehydrate yourself with all that salt.

  6. billrussell | July 15, 2017 at 01:37 | Reply

    the netting, around sapling frames, can be used to trap fish, crabs, mammals, and birds. So you can have meat, fish, lichen cambium, crustaceans, and kelp juice. The net-pen for fish guarantees you enough protein and fat, IF you can choke down that much boiled fish, drinking the broth from boiling fishheads. You then have some free time to look for and process condiments, like wild mustard, that will help you choke down all the fish.

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