The textbook "Fundamentals of Search and Rescue" in Chapter 6 describes the priorities of needs in survival situations. The priorities listed are

  1. Air
  2. Shelter
  3. Rest
  4. Signals/Communication
  5. Water
  6. Food

Placing food last the justifaction is a common one that is given.

[Countless people around the world] have only one meal a day and some not even that. Records from survival experiences show numerous accounts of 40 to 70 day periods with no caloric intake. This fact, coupled with current records showing that most survival situations last a few days at the most, emphasizes that procurement of food in a survival situation should be last on the list of priorities.

My personal anecdotal experience has shown that transitioning from one metabolic regime to another results in a period of days where you are not near 100% functionality as your body adapts and acclimates to the new situation. In long terms situations, more than 5 days or so I have experienced that the body does adapt and performance returns to normal.

In a survival situation, that is expected to last less than 5 days, is there research to suggest that finding high caloric food be prioritized in order to maintain lucidity and physical performance to facilitate rescue, is there any evidence to suggest that de-prioritizing food increases survival, and is there any literature to describe the metabolic transition that I have anecdotally experienced?

  • You have experienced incoherence when fasting for < a week? It seems the typical survival advice barring extenuating circumstances is to shelter in place and wait to be found, which shouldn't require significant food intake.
    – topshot
    Commented Aug 14, 2019 at 13:52
  • 3
    This question could use a title edit so that people don't click it thinking it is actually a question about the starvation transition, which it is not. It is about priorities, and the question only mentions starvation transition tangentially and only as it relates to survival priorities.
    – Loduwijk
    Commented Aug 14, 2019 at 18:42
  • Note: The question specifically asks for research, evidence or literature, not for opinions.
    – user15958
    Commented Aug 16, 2019 at 7:39

5 Answers 5


I think that list is talking about immediate priorities, that is, what you must focus on first to stay alive in a survival situation, not whether food is necessary.

From Backcountry Chronicles, the article Wilderness Survival Rules of 3 – Air, Shelter, Water and Food lists four of the rules like this

Survival Rule of 3 and Survival Priorities

For real survival situations it is better to remember and prioritize by the four levels of the Survival Rules of 3:

  • You can survive for 3 Minutes without air (oxygen) or in icy water

  • You can survive for 3 Hours without shelter in a harsh environment (unless in icy water)

  • You can survive for 3 Days without water (if sheltered from a harsh environment)

  • You can survive for 3 Weeks without food (if you have water and shelter)

The main point of the Rules of 3 that we have to concentrate on the most immediate problem first.

So, for example, you should not risk exposure by leaving shelter to look for food (when the need for food is not urgent).

Or in your six points, not to risk exposure or exhaustion by trying to make a signal (when a search party might find you anyway).

You want to be rescued, but alive.

  • 2
    3 minutes without air or in icy water seems like a heroic upper limit. One minute is probably more realistic, and maybe 30 seconds of that where you're actually still capable of doing anything useful to save yourself.
    – J...
    Commented Aug 14, 2019 at 15:55
  • 1
    @J... I don't suppose these are absolute figures: they are geared to the catchy "rule of 3". You'll last more or less than 3 hours in exposed conditions, depending on how severe the exposure. More or less than 3 weeks without food depending on level of activity. Etc, it's all relative to conditions. Commented Aug 14, 2019 at 16:03
  • 4
    FYI for cold drowning (icy water), you're only dead when you're warm and dead. Cold and dead people can be revived, "Attempt to resuscitate cold victims who appear dead. Some have survived even after several hours of CPR. Check for a pulse and indications of circulation for at least 30 seconds before beginning CPR.." < Dive SSI React Right First Aid... This is for Hypothermia related first aid, so do try for cold drowning in conjunction with drowning first aid as well.
    – Aravona
    Commented Aug 14, 2019 at 16:28
  • 3
    None of those are the point, which is to get out of the water before you think about salvaging your possessions, and so on. Commented Aug 14, 2019 at 16:39
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    @Aravona Fair, but if you're expecting someone to come and save you within 30 minutes then this entire list is a bit moot. From a survival standpoint, assuming no external help is forthcoming, being three minutes in ice water is a situation with self-managed recovery prospects having a very low order of probability. Being in ice water at all, on your own, in a survival situation, even for 30 seconds is a dire situation. Could you get out, dry, build a fire, and warm up before incapacitation sets in (nevermind hypothermia)? If there's a sauna 10m away, sure...we do that for fun. Otherwise...
    – J...
    Commented Aug 14, 2019 at 20:12

is there any evidence to suggest that de-prioritizing food increases survival

Anyone who has ever prioritized food and died of any of the other issues would be evidence that de-prioritizing food would have increased survival. If someone spends a couple days setting traps, snares, and fishing lines only to realize they still don't know how to get fresh water and dies on the third day would regret not prioritizing water.

You note in your quote the emphasis is the typical scenario of being rescued in a few days. Food is barely an issue then, but all those other factors could kill you.

Don't forget to use your brain though! It is your most important tool for survival. If lost in a forest at 40 degrees latitude late spring or early autumn and the weather forecast was no rain for a few days, then tending to a shelter early on is foolish. If I expect a search dispatched within a couple days, I'm also going to ignore the "rest" criteria and spend lots of energy preparing a massive smoke signal that cannot be missed.

Don't throw your logic out the window. Just use the priority list as a reminder of what could kill you first, and remedy that if necessary.

A specific use case...

On the other hand, if you believe that there is a very real possibility that you might be stuck long term, then you need to tend to every one of the needs on that list, and you only concentrate on the higher priority ones to the extent that you need to mitigate them.

For example, if I was extremely lost very deep in the wilderness, neglected to leave any travel plans with trusted people back home, and it's early spring at about 50 to 60 degrees latitude so I do need to worry about severe environmental conditions but the weather is good at the moment, my first two actions would be to set up a covering to protect against rain/snow and to find a water source. The water search would actually come first, not because it's more important than the shelter and rest, but because I want to set up the shelter near enough to the water to assist my long term goals, so I combine shelter and water in my first action. It beats rest temporarily because I'll need to find water anyway, and "search -> water -> rest" is better than "rest -> search -> water (when already dehydrated)".

As soon as I can after shelter + water, I'm going to try to do something for food. Food beats out signals/communication right now because I don't expect anyone to be searching for me, so I expect the signals to be in vain, but I know that I need to avoid starving.

This scenario was forced on us by negligently not informing anyone of our travel plans. Remember to provide that information to at least 1 trusted individual before your travel! If I had not been so foolish in this use case, I could have prioritized signals and drastically improved my survival odds.

But since it is what it is, working on development of food sources comes before signals. But as soon as you can either break from food or multitask, then I'd work on signals. Eventually the situation might come that I can signal for help, so I do want to have that option available.

Air was never at risk in this use case.

So in this specific use case, the situation-specific order of events that I would have thought about ended up being 1) water 2) shelter 3) rest 4) food 5) signals/communication, and air is not even on the list.

That does not mean that air is not the highest priority - it is. Or that sheltering from rain and snow in that environment is not more important than water - it is more important than water. But I would have used the combination of the survival priority list with my knowledge of my unique circumstances to juggle priorities and maximize long term survival.

In fact, if you want to follow your priority list strictly, one could even put it this way: "Air? Satisfied. Shelter? I have a tent (tarp, bivy bag, whatever) so I can shield from the rain or snow quickly if needed, and weather's ok for now so satisfied. Rest? Not satisfied, so I should get a rest as soon as is reasonable. Signals? Not satisfied at all, and I was dumb so nothing I can do about that for now. Water? Almost out, not satisfied, get more as soon as possible. Food? Almost out, but it can wait since I have more pressing needs." Running through the checklist just like that and following it to a tee would get you results similar to what I said above, with the only difference being water wasn't queued up as efficiently.

  • 2
    It's a good answer, especially being aware of one's situation and prioritising accordingly. The premise of "location unknown" also involves another general rule: stay where rescuers will expect you to be. In your example you would need to make a calculated decision about whether to attempt to walk out, or stay where you can make a signal. The whole thing is about risk management. Commented Aug 14, 2019 at 20:44
  • @WeatherVane "...walk out or stay..." True. In my mind, when I said "extremely lost very deep in the wilderness at latitude 50-60" I was thinking of being so deep in the Canadian wilderness and so many miles from the nearest trail (presumably from trying to fix your situation and only getting more lost) that the odds of stumbling onto anything useful are very slim. That's what I had in my head. Hopefully it would not come to that. At that point, you might need to essentially live out there and hope that you thrive to where you can stockpile enough food to risk a long trailblazing walk out.
    – Loduwijk
    Commented Aug 14, 2019 at 21:49
  • Alternatively, I am curious now: If someone from the US went for a long hike in Canada and got into this situation and nobody knew they were even lost or in Canada, I wonder how useful/successful it would be to simply start a massive smoke signal and keep it going all the time for weeks or months. I wonder if any aircraft would ever realize something is amiss. Scary thought. Better take GPS, beacon, or at least a signaling mirror or strong flashlight.
    – Loduwijk
    Commented Aug 14, 2019 at 21:53
  • You're going that far into the backcountry without a PLB or the like? Commented Aug 16, 2019 at 2:34
  • The question specifically asks for research, evidence or literature, not for opinions.
    – user15958
    Commented Aug 16, 2019 at 7:38

Another factor here: Depending on where you are you very well might find that attempting to obtain food costs you more energy than whatever you find provides.

I'm thinking of my usual hiking territories. At lower elevations I have seen the occasional lizard at a range where it wouldn't be a hail Mary to try to nail it with a rock. Also at lower elevations I have seen rabbits--but the terrain has never been conductive to setting snares.

At higher elevations I have seen birds--never at a range I could hope to bag one, though. There are also occasional horses, they are reasonably tolerant of humans but I would seriously doubt my ability to bring one down.

If I'm in a survival situation out there I'm going to be looking for shelter to reduce heat loss, not looking for food.

  • The question specifically asks for research, evidence or literature, not for opinions.
    – user15958
    Commented Aug 16, 2019 at 7:39

While it looks like it has changed, Outward Bound used to routinely include a 3 day solo without food. If I recall correctly, a poncho tarp shelter was provided and you were located near clean water. You were expected not to make a fire or hike out. After the 3 days, you had to hike a few miles to the common gathering spot and were given a moderate meal. Then the trip continued. Apart from the stress, I think this is a reasonable approximation of a survival situation in which you believe there is a good chance you will be found.

I went to a rad high school that included a 10 day winter backing trip in the white mountains of NH. It was Outward Bound inspired and included a 3 day solo. We were given a poncho tarp, sleeping bag, and allowed fires. We were also given a small ratio of food. My guess is something like 1500 calories for the 3 days. Like Outward Bound, you were hungry when it started and were expected to hike after it ended. There was never a case where a student was injured or unable to continue.

For at least periods of 3 days, food really is not an issue and young and relatively inexperienced people can survive with minimal supplies.


I don't know. I think it really depends on the situation but some of them are critical.

1 Air and other environmental elements like extreme heat, cold, ice water, blizzard ice storm, avalanche...etc should be 1st priority because they would kill you in minutes.

2 Once you pass that immediate fatal condition then I personally think it's exposure to both environment and wild life. This depends on where you are though. Sandy vacation beach in the Bahamas is completely different than top of an ice cap.

3 A plan. I think that once you are out of dying in hours then you can sit down and have a plan. Maybe to find water or seek for a way to signal for rescue. Just sit down and see what you have with you, what you have around you and what you need.

4 Water > Shelter > Signal. Imo is most common where you need a shelter to prevent exposure but not immediate enough so you can actually move around looking for water.

5 Food is last because you don't really need it until the 6th-8th day without food. Maybe you will feel rough for day 2 and 3 but day 4+ should make you feel better. You will need some sort of starch or sugar for day 8+ to prevent you from feeling weak but it's pretty much your brain is hoping for some sugar.

  • The question specifically asks for research, evidence or literature, not for opinions.
    – user15958
    Commented Aug 16, 2019 at 7:38

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