Starvation Mode: What Is It & Are You In It?

Let’s paint a picture…

You decide you want to lose some weight, you know, drop a few pounds to feel and look a little better. The weight gain has a snuck up on you and you realise it’s time to take control, after all the holidays are coming and you want to look your best.

You calculate your calories, set your macros and start tracking your food intake using the MyFitnessPal app. Weighing yourself daily you see the weight begin to drop off and all goes well over the following weeks, you’re feeling on top of the world.

A couple of months down the line your weight loss begins to slow down before stalling all together, there’s even days where you’re a little heavier than normal.

What the hell’s going on?

You give it another couple of weeks but nothing changes. You drop your calories down a little lower and do a little extra exercise. Things initially appear to be better but another couple of weeks down the line and the scales refuse to budge again.

You repeat this process a couple of times, making incremental progress but mostly spinning your wheels.

By this point you’re deep into your weight loss journey and this shouldn’t be happening. You begin to worry, “why am I not losing weight”, “what’s going on?”, then it dawns on you, you must be in starvation mode.

Your body is shutting down and preventing weight loss, you might even be gaining a little weight back because of it.

You decide the best thing to do is bump your calories back up to “re-set” your metabolism and pull yourself out of this dreaded starvation mode, then you can go back to losing weight.

However, when you do this you end up back at square one, gaining back all the weight you lost, plus a bit more and being no better off than when you started over half a year ago.

Starvation mode has reared its ugly head again.

Except, has it? Is that what’s really going on here? Or is it something else?


What is Starvation Mode?

The funny thing with the starvation mode is that what most people think it is, is not what it actually is, and this is where the problem begins.

The way most people see starvation mode is as follows,

“Eating too few calories, for too long of a period will cause your metabolism to slow down so much that it will prevent weight loss and even cause weight gain.”

The solution to this definition of starvation mode?

“Eat more calories to ‘re-start’ your metabolism and get out of starvation mode before going back into a calorie deficit to lose weight again.”

However, whilst this might seem like the logical thing to do (if this is your definition of starvation mode) this cycle of weight loss, followed by starvation mode, having to re-start your metabolism before going back into a calorie deficit is not only fundamentally flawed but it is also not happening as a result of your body entering ‘starvation mode’.

The truth is whilst starvation mode is a real thing this definition of it is bullshit. For the average gym goer or quite frankly anyone else it’s not something you ever need to worry about.

The actual definition of starvation mode or the starvation response (1) is,

“a state in which the body responds to prolonged periods of low energy intake [by burning] free fatty acids from body fat stores, along with small amounts of muscle tissue to provide required glucose for the brain. After prolonged periods of starvation, the body has depleted its body fat and begins to burn primarily lean tissue and muscle as a fuel source.”

As you can see your body’s response to starvation i.e. reduced food intake or no food intake is to continue burning body fat for energy before moving to muscle mass for the same purpose.

It doesn’t halt fat loss or cause weight gain, it will continue to break down either fat or muscle mass to create energy until there is nothing left to use.

The starvation response in its true form is completely irrelevant to weight loss conversations for the average person trying to lose weight for a few reasons:

  • You should not be trying to lose fat by using a severe (more than 500) calorie deficit

  • You should always be weight training to help preserve muscle mass

  • You should not be concerned with reducing body fat to levels which require you to burn your muscle mass for energy

  • ‘Starvation mode’ does not cause weight gain or a plateau in weight loss

The only reason it keeps coming up is because of a fundamental misunderstanding of what actually happens during the ‘starvation mode’. To illustrate this, we can look at a famous study conducted by Dr. Ancel Keys.


The Minnesota Starvation Experiment

November 1944, World War II is raging but all is quiet in the hallways of the University of Minnesota Football stadium as 36 young men are shown to their new home for the next year.


They volunteered to be part of an experiment that was to be conducted by Dr. Ancel Keys and his team of scientists (2).

The poster used to recruit participants into the study

The poster used to recruit participants into the study

At the time, the effects of hunger and starvation were rampant in heavily rationed countries and whilst there was anecdotal evidence of its effects there was little to no actual scientific literature.

Keys and his team set out to change this.

Over 200 individuals applied to take part in his study but in the end only 36 were chosen. They were selected on the basis of their good physical and mental health as well as their ability to bond with others in difficult circumstances.

The aim of the experiment was to monitor the physical and psychological effects of semi-starvation on the men whilst also examining the most effective way to help individuals recover and rehabilitate after starvation.

Note: If starvation mode as most people see is the correct definition then we would expect to see most if not all participants lose some weight before plateauing or even gaining weight during the study.

Ancel’s study required the men to lose 25% of their body weight and was split into 4 phases.

  1. Three months of eating a normal maintenance diet of 3,200 calories a day

  2. Six months of semi-starvation using a calorie restricted diet of 1,570 calories a day*

  3. Three months of restricted rehabilitation consisting of 2,000 – 3,200 calories a day

  4. Eight weeks of unrestricted rehabilitation where no limits were placed on calories**

*Several participants were kicked out of the study for cheating on their diet.

**Only 12 of the 36 stayed on for the non-compulsory 4th phase. During this period of unrestricted eating they often consumed 5,000 calories a day with one man eating 11,500 on one day.

During the entirety of the study participants were required to walk 3 miles a day as well as work in the lab for 15 hours week and participate in education activities for 25 hours a week.


What Did They Find?

They found that prolonged semi-starvation led to emotional distress and depression in most men. They also noticed that all men lost interest in sex, became obsessed with meals time and frequently got irritated if meals were not served on time.

However, most importantly to this discussion the researchers found that during phase 2, although there was a marked decline in the subject’s basal metabolic rate all men lost weight and continued to lose weight throughout this period.

In fact, they kept on losing weight until they got all the way down to 5% body fat and could no longer lose any more weight without risking serious health implications (3).

Photos of 2 of the participants from the study

Photos of 2 of the participants from the study

Does this mean you should use semi-starvation to lose weight?

HELL NO! You should never do this BUT there are 2 important points we can take from this study:

  1. If you’re in a calorie deficit you will lose weight

  2. Your caloric needs will decrease as you lose weight


Why Do People Think They’re in Starvation Mode?

It’s a fair question and the answer is adaptive thermogenesis.

Adaptive thermogenesis is the name given to the slowing of your metabolic rate when you remain in a prolonged calorie deficit. The greater the calorie deficit and the greater the duration of the deficit the higher this reduction in metabolic rate will be.

However, this reduction in your metabolic rate is not enough to invoke this so called ‘starvation mode’ and prevent weight loss. At most you’re looking at the slowdown of your weight loss progress over time as your calorie needs change due to this metabolic change combined with your change in weight (5).

As you lose fat and your body weight goes down so will the number of calories you need to maintain your weight, which means the number of calories you can eat and lose weight will also change.

For example, what worked for you at 280 lbs won’t necessarily work for you at 220 lbs as your body’s needs will be different. It’s this change in caloric need and the small impact of adaptive thermogenesis that causes you to stop losing weight, not starvation mode kicking in.

What’s really happening when you claim to be in starvation mode is actually very simple.

Whatever you think (bad luck, bad genetics, starvation mode, etc..) if you’re not losing weight or are gaining weight then guess what...YOU’RE NOT IN A CALORIE DEFICIT.

If you think you are…I’m sorry but you’re wrong.

Hidden calories, a reduction in exercise, adaptive thermogenesis and a change in weight are the culprits and if you address these issues and make sure you’re actually in a calorie deficit then weight loss will resume.

The bottom line is that ‘starvation mode’ as most people see it is not accurate and certainly not a concern. Your concern should be, whether or not you are in a calorie deficit.

Another point to make is that the reason you think you’re gaining weight in ‘starvation mode’ is generally for one of three reasons:


You’re Over-eating Without Realising

Easily done and easily rectified. After a while of tracking your intake and seeing results you will naturally relax and a little complacency will settle in and maybe you’ll stop accounting for the milk in your coffee or the oil used in cooking. Maybe you’ll begin eyeballing things or miscalculating. Whatever, it is these calories will slip by unnoticed and result in you thinking you’re in a calorie deficit when you’re more likely at maintenance or in a surplus.

The solution: start measuring your intake again and get back on track, double or triple check your daily calories if you need to.


You’re Gaining Muscle

Depending on your training experience, starting body weight and workout routine, it’s possible that you’ll gain some muscle even when eating in a calorie deficit. This means although you’ll be losing weight your scale weight may appear to be stuck when in fact it’s because you’re also gaining muscle that it gives the appearance of a lack of progress.


The Non-linear Results of Weight Loss

Your weight will fluctuate day to day depending on a variety of factors, including by not limited to: hydration, bowel movements, exercise, food intake and bloating. You can reasonably expect to see fluctuations of in general a couple of pounds across the week and possibly more. This is completely normal and again highlights the importance of weighing yourself daily and taking a weekly average.

Ok so maybe you’ve addressed these issues and your weight still isn’t moving. What do you do then? Well, chances are you’ve hit what’s called a weight loss plateau.


Summing Up

Yes, starvation and the starvation mode (also known as starvation response) is a real thing but it’s not what most people think it is and for this reason it’s not something the average dieter needs to be concerned with.

However, due to a process called adaptive thermogenesis your caloric needs will decrease as your body weight decreases and for this reason you may hit a weight loss plateau. When this happens, there are 3 simple solutions you can use to get your fat loss going again; recalculate your calories, introduce refeed days or use a diet break.


Additional Information & Interesting Facts

In 2005 Leah M. Kalm and Richard D. Semba published an article titled “They Starved So That Others Be Better Fed: Remembering Ancel Keys and the Minnesota Experiment” in The American Society for Nutritional Sciences (6).

In this paper, they discuss Key’s study and share some fascinating details that provide a deeper insight into the minds of the participants.

One participant named Harold Blickenstaff was recorded as having said:

“I don’t know many other things in my life that I looked forward to being over with any more than this experiment. And it wasn’t so much … because of the physical discomfort, but because it made food the most important thing in one’s life … food became the one central and only thing really in one’s life. And life is pretty dull if that’s the only thing. I mean, if you went to a movie, you weren’t particularly interested in the love scenes, but you noticed every time they ate and what they ate.”

Another participant, Samuel Legg tells of the impact semi-starvation had on him mentally;

“I was walking along … [with my] buddy … it was deep into the semi-starvation, and we were tired … we would look for driveways when we got to a cross street … so we wouldn’t have to walk up one step to get from the road to the sidewalk … We were tired and weak. And so, we were standing at a corner waiting for a light or something, and a kid came along on a bicycle, and he was really moving, pumping away … And I looked at him and said, “Wow, look at that boy. He’s really whizzing.” And then I said to myself, “I know where he’s going. He’s going home for supper. And I’m not.” And then for a very brief, I hope it was brief, moment … I suddenly hated the boy … I hate at this point to tell you this, because it doesn’t speak very well for me. But I remember … with … horror that I could feel such a thing. So utterly irrational, but there it was. And you ask an experience that I remember; I sure remember that. That was rough.”


60 Years Later

Almost 60 years after the Minnesota Experiment, 19 of the 36 original participants were still alive and 18 were interviewed in an oral history project conducted from July 2003 through February 2004.

A letter was sent to each participant, inviting him to take part in a tape-recorded, structured interview. After oral consent was obtained, 14 participants were interviewed in their homes or offices, and 4 were interviewed by telephone.

Perhaps most interesting of all is that all things considered…

“the participants agreed that if the clocks were turned back, they would again make the same decision to participate, even after having experienced the physical sacrifice required.”

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