What is the Minimal Diet for Survival?

“To eat is a necessity, but to eat intelligently is an art.” – La Rochefoucauld

We all know the Rambo-stories about diehards getting stuck in remote deserts, jungles or even at sea, surviving on a bare diet of turtle blood, forest grubs or grilled rats. Those people are survivors in the literal sense of the word, but most of them were not actually getting the right amount of nutrients to healthily sustain themselves over a longer period of time. That’s why today we’re exploring the minimal diet needed for a human being. Not to merely delay death, but to actually stay alive and healthy.

As most survival readers know, the human body can roughly survive without food three weeks. However, this is an excruciating and painful process. Even a daily intake of 600 calories (that’s an average grilled rat) is significantly lower than what is required for long-term survival. In such a situation, the body resorts to breaking down its own organs to sustain itself. 

Practical implications of this blog

Why would I want to know this, you may wonder? Below I listed a few reasons where this knowledge comes in handy. 

Doomsday prepping 

You can use the numbers to calculate if you’re prepping for disaster. Take the daily minimal need of all your family members in active circumstances, or less when you’re prepping for nuclear disaster in an underground bunker and multiply it by the number of days, you’re willing to stock up for. 

Hiking provisions

Another useful application is to calculate your needs for a long hiking adventure in uninhabited areas, scarce of resources. 

Am I overeating?

For fun, count out the number of calories taken for a couple of days and compare that number to the number that matches your activity level (see calculator below). Most people will find out they’re likely to be overeating. But before radically changing your diet, it’s best to speak to a professional dietician to determine your ideal calorie intake.

Can we trust the numbers?

The number of calories required for survival depends on various factors, including age, gender, weight, activity level, medical condition, and environment. As a general rule, it is recommended that adults consume at least 1,200 calories per day to maintain basic bodily functions.

This is a pretty unreliable generalization that won’t help you in that desert or jungle. In a survival situation where food is scarce, a person’s calorie needs may be far greater due to increased physical activity and stress. Yet, if food is extremely limited, a person may be able to survive for a short period of time on as few as 800-1,200 calories per day. It is important to note that severely restricting calorie intake for an extended period of time can lead to malnutrition, other health problems and ultimately death.

How many calories do I need to keep my organs running normally?

Men typically require more calories than women, and those who engage in high levels of physical activity need more than sedentary individuals. While extremely active people can consume more calories without gaining weight, most individuals do not require more than 3,000 calories daily. In fact, overconsumption is a much bigger problem in most countries than malnutrition. The numbers are no joke, with a whopping 2,7 billion people in the world having overweight versus ‘only’ 663 million undernourished ones. Food for thought, I guess.

To maintain your current weight, it is necessary to consume at least the same amount of calories needed to operate the organs For instance, a male weighing 175 Lbs. and measuring 5 foot 9 in height is said to need around 1900 calories a day to support the functioning of his organs.

But if he engages in activities such as walking, running, and daily chores that require more calories, his calorie intake should be higher. Of course, food isn’t just about calories, otherwise we could just survive on plain rice alone, which we can’t. Therefore, it is essential to keep in mind the right balance of vitamins and trace minerals needed by the organs; otherwise, malnutrition can occur, leading to slow death, even if you consume enough calories.

So how to know how much your particular body needs to survive healthily? 

BMR is the key

A crucial number for survival is the Basal Metabolic Rate (BMR). This number represents the amount of calories your body burns to perform essential life-sustaining functions. Also known as Resting Metabolic Rate (RMR), this is the number of calories burned if you were to stay in bed all day. To determine their body’s metabolism rate, many people use this basal metabolic rate formula.

Your BMR is responsible for approximately 60-70% of the calories you burn, including the energy required to sustain vital functions such as the beating of your heart, cell production, respiration, body temperature regulation, circulation, and nutrient processing. Various factors, including age, weight, height, gender, environmental temperature, diet, and exercise habits, influence your unique metabolism rate, or BMR.

How to know your BMR?

Need to determine your BMR? There are two common formulas that can help.

The first formula is the Harris Benedict equation, which has been in use in some form since 1919. This equation estimates the amount of energy your body uses to stay alive. To use this equation, you need to input your weight in kilograms, height in centimeters, and age in years.

  • For women, the Harris Benedict equation is: BMR = 655.1 + (9.563 x weight in kg) + (1.85 x height in cm) – (4.676 x age in years)
  • For men, the Harris Benedict equation is: BMR = 66.47 + (13.75 x weight in kg) + (5.003 x height in cm) – (6.755 x age in years)

Once you have inputted your information, solve the equation to determine your BMR in calories. Keep in mind that BMR is the amount of energy your body would burn if you did absolutely nothing all day.

The second formula is the Mifflin-St. Jeor equation, which is newer, but just as widely used as the Harris Benedict equation. Like the first equation, you will need to input your weight in kilograms, height in centimeters, and age in years.

  • For women, the Mifflin-St. Jeor equation is: BMR = (10 x weight in kg) + (6.25 x height in cm) – (5 x age in years) – 161
  • For men, the Mifflin-St. Jeor equation is: BMR = (10 x weight in kg) + (6.25 x height in cm) – (5 x age in years) + 5

Both equations will yield similar results for the same person. However, if you don’t feel like doing the math yourself, there are plenty of online BMR calculators that can do the work for you. Simply enter your information and you’ll get your BMR in seconds!

I figured out I only need between 1650 and 1700 calories a day, but when involved in physical activity such as hunting, fishing, carrying firewood and fetching water it shoots up to between 2700 and 3000 quickly. From this, we can conclude that the bare BMR can be a good basic indication, but doesn’t really reflect your reality when stranded in the desert. 

Extreme survival stories

Extreme survival stories

Despite all the logics and calorie formulas we apply, the human body is a tough one, and some people, including ones described in our earlier stories, defy all odds. Take the example of Mila Lana, a Russian woman who grew up in abject poverty and with chronic malnutrition in a Siberian city which sees winters as cold as−71.7 °F.

‘For about 8 years, my family (three people, 1992-2000) ate one loaf of bread and several cups of sweet tea a day. From time to time we drank courses of vitamins, sometimes we ate berries and fruits, juices (in summer), sometimes we went hungry for one or two weeks per month. However, we survived. We suffered more psychologically than physically.

Mila reasons that her body needs about 1200 calories per day and noticed that if the food is less than 1000 calories per day, she started losing weight. “The loaf of bread had 1,632 calories / 3 = 544 calories, + sweet tea (1 glass about 65 calories * 5 = 325 calories). Total: I got about 870 calories per day. The lack of food was compensated for in the summer. In general, my physical condition was normal. But psychologically, it was hard.’

Worse even, was life for prisoners in concentration camp Auschwitz, where they were given between 1000 and 1300 calories a day. The inmates were required to engage in strenuous physical labor for 12 hours a day while on this meager diet. This, besides the abject and violent conditions in these death camps, turned their average lifespan into just 3 months. This was due not only to the insufficient intake of calories and protein, but also the absence of crucial nutrients such as vitamins, which undoubtedly contributed to the shortened survival rate.

Can I live on 1200 calories?

If your BMR says 1200, then there’s a good chance 1200 calories is enough for you in sedentary condition. Remember that many factors will increase the number of calories needed. But just to show that it doesn’t have to be that sad, I compiled a low-calorie sample menu for you all to see it doesn’t even have to be so grim.

Low-calorie breakfast:

1 slice of whole grain toast (80 calories)

1 scrambled egg (90 calories)

1 small apple (80 calories)

1 cup of black coffee or tea (0 calories)

Total calories: 250

Low-calorie lunch:

3 oz of grilled chicken breast (140 calories)

1 cup of mixed vegetables (50 calories)

1/2 cup of brown rice (100 calories)

1 small orange (50 calories)

1 cup of water (0 calories)

Total calories: 340

Low-calorie dinner

3 oz of baked salmon (180 calories)

1 cup of steamed broccoli (55 calories)

1 small baked sweet potato (100 calories)

1/2 cup of sliced strawberries (25 calories)

1 cup of water (0 calories)

Total calories: 360

Yay, snacks included (choose one though)

1 small container of low-fat Greek yogurt (80 calories)

1 small handful of almonds (100 calories)

1 medium carrot with 2 tablespoons of hummus (90 calories)

Total calories for snack: 80-100

A low-calorie diet doesn’t even sound so bad, right? Just remember to not take this as dietary advice! This blog is about survival in extreme conditions, and to know how many calories you need to stay alive. At most, this story might show that there’s a good chance you’re structurally eating way more than your body needs. However, if you want to lose weight, don’t blindly follow BMR-numbers, but rather talk to a professional dietician since each body has its own particular needs to function properly.


With the BMR-calculation model this blog gives, we can learn about the bare minimum number of calories we need in extremely sedentary circumstances, assuming this number will shoot up as soon as we get physically active. So, while BMR can serve as an indication, know that you’re never in control over the situation you may find yourself in and that, in survival mode, you’re not always that likely to hunt and gather the 3000 calories needed for long-term upkeep of the body. Luckily, most people are found within 72 hours after going missing, which is much too short to die of hunger. 

As always, stick to the basic order of survival: water, fire, and shelter before worrying about food. Not having your basic three organized is a much bigger danger than hunger in emergency situations. 

In any case, the BMR gives you a fair estimate of whether your calorie intake matches your activity level and body type, whether lost at sea, clueless in the steamy Amazon or even as a sedentary desktop survivalist at the home front. 

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