"Metabolic damage" and "starvation mode" - refuted by science
If you want to know what science has to say about "starvation mode" and "metabolic damage", you should read this article
The most important facts at a glance:
- "Metabolic damage" is not real. They have never stopped anyone from losing weight and there is no need to fix them with complex and cumbersome diet voodoo.
- "Starvation mode" is real in a sense, but it's not nearly as dramatic as many people think.
- There are three reasons you can stop losing weight while dieting "for no good reason": You retain water, you build muscle, or you overeat (and this is more common than you might think)
If you're reading this article, there's a good chance you've already experienced the following scenario first-hand:
You're dieting to lose weight and you're doing everything right. You.
- You maintain a calorie deficit
- You eat enough protein
- You stick to your nutrition plan
- You train regularly with weights
- You limit your cardio training
And at first, everything is going more or less according to plan. Your weight and waist size have decreased and your muscle definition has improved - everything was going according to plan like clockwork.
And then suddenly your progress comes to a standstill.
For no apparent reason, the pointer on the scales stops moving and your reflection in the mirror no longer changes. You know the concept of energy balance and - determined to keep the ball rolling - you continue to reduce your calories and increase your cardio.
It works, of course...up to a point. And then you're stuck again - and this time you feel even more emaciated than before.
What can you do? Is this the maximum your body can take? Have you reached your "set point"? Is a lower body fat percentage simply not achievable for you?
And then you hear about "starvation mode" and "metabolic damage."
You'll find stories about people - typically women - who say that even with extremely low calorie intake and many hours of exercise per week, they are not losing weight and claim that (alleged) metabolic abnormalities caused by calorie restriction are responsible.
Basically, this story goes like this:
Dieting gradually reduces your basal metabolic rate dramatically, ultimately halting fat loss and necessitating lengthy "recovery programs" to repair the damage - if you ever manage to regain a healthy metabolism at all.
Hence the term "metabolic damage".
When your body goes through the complex set of metabolic, physiological adaptations that supposedly lead to metabolic damage, your body is said to be in what is known as "starvation mode". This supposedly starts on the first day of your diet and gets progressively worse and worse over time.
How real are these claims really? Well, it all looks like this:
- "Metabolic damage" is not real. They have never stopped anyone from losing weight and there is no need to fix them with complex and cumbersome diet voodoo.
- "Starvation mode" is real in a sense, but it's not nearly as dramatic as many people think.
In this article, you'll learn why this is the case.
In addition, you'll also learn the real reasons why your weight loss stalls and what you can do to break through weight loss plateaus with ease.
Let's get to the point.
What is "metabolic damage"?
According to most theories, the term 'metabolic damage' refers to a condition where multiple physiological systems have been disrupted and as a result your metabolism is burning less energy than it should.
In other words, it is a hypothetical state in which you burn fewer calories than you should based on your weight and activity levels. Furthermore, once your metabolism has been damaged, it is said to remain paralyzed even if you stop dieting and simply try to maintain your weight.
This is called "metabolic damage" because, according to this theory, your metabolism is literally damaged to some degree and action is needed to repair the damage.
(And in case you are not familiar with this term, your body's metabolism is a collection of physical and chemical processes that serve to produce, maintain and destroy material substances and make energy available).
The cause of metabolic damage is said to be running a calorie deficit and/or starvation diet for too long, and too much cardio training is also often seen as a cause.
If you stop losing weight after a period of dieting for no apparent reason or struggle to prevent weight gain after a prolonged diet, some people will claim for this reason that you may be suffering from metabolic damage that needs to be repaired.
The "evidence" to support all of this is almost always stories. Stories of people who can't lose weight despite eating less than a hundred calories a day or even stories of people who gain weight despite eating almost nothing and doing intense exercise.
And so people all over the world have been convinced that dieting has messed up their bodies - perhaps even irreversibly - and that their only hope of getting back to normal is to take dietary measures.
How is metabolic damage supposed to be repaired?
The typical protocol for repairing metabolic damage is simple: increase your daily calorie intake in small increments - usually 50 to 100 kcal - each week until you reach your calculated daily energy needs.
In some cases, precise instructions are also given regarding the macronutrient breakdown.
The basic idea behind this approach is that by slowly increasing calorie intake (rather than drastically increasing calorie intake as most people do after a diet) you allow your "damaged" metabolism to "keep up" and process food efficiently, which should result in a gradual increase in metabolic rate without unwanted fat gain.
This is commonly referred to as "reverse dieting" and while it is indeed a good idea to gradually increase your food intake after a prolonged period of calorie restriction, you don't have to do this for the reasons usually given (more on this later).
What is 'starvation mode'?
The idea behind 'starvation mode' is similar to the idea behind the concept of 'metabolic damage'.
Here's how it works: If you're too aggressive in your calorie restriction, then your metabolism will slow way down, making it more or less impossible to continue losing weight without eating less than a lean model.
According to many fitness gurus, if you stay in a starvation mode for too long, the next phase of "punishment" will begin: Muscle loss and fat gain.
We are told that the only way to avoid this is to lose weight slowly through a small calorie deficit (10 to 15%). We are told that if we get too greedy, we will pay for it later.
The way most people describe it, metabolic damage and starvation mode work together in the following ways to hinder your progress:
- You eat too little and lose weight too quickly.
- You put your body into starvation mode and your weight loss stops.
- You eat less and exercise even more, which further exacerbates this reaction and leads to metabolic damage.
- The longer you stay in this state, the less weight you will lose regardless of what you do and the more damage you will cause that will need to be repaired later.
Now, as you're about to see, there's a grain of truth to all of this, but as with most things that everyone in the fitness world "knows", more of it is false than true.
Does weight loss actually damage your metabolism?
No.
Okay, I'll explain this.
To understand the true science of fat loss, you need to start with the principle of energy balance and understand how only your energy intake and energy expenditure dictate your weight gain and weight loss.
Once you understand this, you will realize that significant weight loss requires you to consume fewer calories (energy) than you burn over an extended period of time.
For most people, this is where the learning process ends. They wanted the one great trick to melt away their belly fat and life preservers and they now know it: eat less and move more.
What they don't know, however, may come back to haunt them later, because calorie restriction does more than simply reduce overall fat mass - it also affects your metabolism in different ways that can make fat loss increasingly difficult over time.
In short, when you restrict your calorie intake to lose fat, your body will try to reduce your calorie expenditure and increase your calorie intake. By doing this, it wants to eliminate the energy deficit and create a balance between calorie intake and expenditure, thereby bringing fat loss to a halt.
The truth is that in order to lose fat, you have to force your body to do something it doesn't want to do (mild and prolonged starvation) and in the spirit of self-preservation, your body has developed self-defense mechanisms that it uses to fight back.
Let's take a look at the most important of these...
Your basal metabolic rate will drop.
Your basal metabolic rate is the amount of energy your body burns at rest. Your body's biggest energy consumers are your organs and your muscles (these are the primary determinants of your basal metabolic rate).
When you expose your body to a calorie deficit, hormonal adaptations take place that cause your body to burn less energy at rest.
The primary hormones involved in these adaptations include leptin, ghrelin, thyroid hormones and testosterone, all of which are affected unfavorably by a calorie deficit.
The thermic effect of food decreases.
The thermic effect of food is the amount of energy expended in the consumption, digestion, absorption and storage of food.
Scientific research has shown that the thermic effect of food accounts for about 10% of daily calorie consumption, with the exact amount varying based on the macronutrient composition of the diet.
While calorie restriction does not appear to directly reduce the thermic effect of food, a reduction in overall food intake will naturally result in a reduction in overall energy expenditure.
You burn fewer calories through "spontaneous" physical activity.
Every day you perform varying amounts of spontaneous activities such as walking around while talking on the phone, going to the bathroom, drumming your fingers on the table while reading or bouncing your legs while thinking.
The energy burned by these activities is known as NEAT (non-exercise activity thermogenesis) and plays a much bigger role in your daily energy expenditure than most people think.
Scientific research has shown that NEAT can vary by as much as 2,000 kcal per day from person to person and the same research suggests that by taking simple steps to increase overall activity levels such as taking the stairs instead of the elevator, walking short distances instead of driving, doing housework while watching TV, etc., people could burn an additional 350 kcal per day.
When you are in a calorie deficit, the body reduces its spontaneous activity levels and thereby reduces its daily energy requirements - often significantly.
What's more, scientific research shows that this adaptation can be maintained for some time after you return to a normal diet (this is one of the reasons why weight gain after dieting is so common).
You burn fewer calories during exercise.
When you reduce your body weight, you also reduce the amount of energy used during exercise (it takes more energy to move a heavier body).
There's more here than may seem obvious at first glance, as studies have shown that energy expenditure remains lower than normal even when body weight is artificially increased during weight loss.
Let's put it all together
As you can see, your daily energy expenditure is something of a moving target and one of the challenges during a diet is to adjust your exercise and nutrition plan accordingly to ensure that your energy deficit remains high enough for you to continue to lose weight.
The described changes in your basal metabolic rate, NEAT, the thermic effect of food, etc. are also known as "adaptive thermogenesis" and are your body's primary "countermeasures" during weight loss.
They can be very effective. If you don't know how to use them properly, they can significantly slow down the rate of your weight loss or even bring your weight loss to a halt.
What they can't do, however, is 'damage' your metabolism - even if you're cutting your calorie intake, eating too little protein and doing too little strength training.
While you can expect greater reductions in your basal metabolic rate if you do these things, the effects will be much less than many people would have you believe.
Several studies have shown that the reduction in metabolic rate associated with dieting, even with long periods of very low calorie dieting, only ranges from 5 to 15%.
Furthermore, it took a reduction in body weight of about 10% to produce the larger double-digit reductions and most of the research in this area was done with people who made pretty much every classic mistake: they ate too little, ate too little protein and did no resistance training.
We also know that these effects, although they can persist long after weight loss has ended, can easily be reversed by increasing calorie intake, training with weights and eating a high protein diet.
You might be wondering what happens if you do everything right - that is, if you use a moderately aggressive but not insane calorie deficit, eat about 2 grams of protein per kilogram of body weight per day, and do a few hours of heavy resistance training per week.
Well, studies have shown that this approach to fat loss can actually increase your metabolic rate and muscle mass.
So the term "metabolic damage" is a misnomer. The more accurate term would be "metabolic adaptation", which can work for and against you depending on your goals and your actions.
Is starvation mode real?
No, not in the strict sense that most people understand this term.
As you already know, your body responds to calorie restriction with countermeasures designed to halt weight loss (adaptive thermogenesis), but there is no mode that the body goes into and no physiological switch that is flipped to make further weight loss impossible.
The best example of all this that I know of is one of the most extreme studies ever done to study human metabolism: The Minnesota Starvation Experiment.
This experiment began in 1944 as the end of World War II was approaching and its purpose was to find the healthiest way to help millions of starving people in Europe regain a normal body weight.
As you've probably guessed, this experiment involved starving people - and by starving, I mean starving in the truest sense of the word.
The scientists took 36 volunteers (who were given the choice of either going to the war front or taking part in this experiment) and, to replicate conditions in an average prisoner of war camp, they had to perform several hours of physical labor per day and walk 22 miles per week while being put on a diet that provided them with only about 50% of their average daily energy requirements - for a period of 6 months!
As you can imagine, things got really gruesome. By the end of the study, the men were nearly starving and one had even cut off several of his fingers to end the experiment early.
And what about their metabolism? Was their metabolism as severely damaged as advocates of the concepts of "metabolic damage" and "starvation mode" would predict?
No.
After losing an average of about 25% of their body weight, their basal metabolic rate was about 20% lower than scientists would have estimated based on their body weight.
In other words, after 6 months of the most extreme weight loss program, their metabolic rate was about 20% below normal.
During the next phase of the study, the subjects were put on a "recovery diet" that would allow them to regain most of the weight they had lost, and after 12 weeks of this diet, their metabolic rate was re-examined.
This time the average metabolic rate was only about 10% lower than would have been normal and in some cases it had even returned to normal as if nothing had happened.
Not great news, but not too bad considering what they had put their bodies through.
For example, if you started your weight loss journey with a basal metabolic rate of around 1,800 kcal, then played Auschwitz for 6 months and then regained the lost weight, you could expect a basal metabolic rate of around 1,600 kcal per day. That's not ideal, of course, but it's also not enough to make any future weight loss impossible.
It's also worth noting that, according to a new study, when looking at the long-term data (rather than the first 12 weeks of recovery), there is no evidence that any of the study participants suffered any residual 'metabolic damage'.
This means that everything returned to normal and some people simply took longer than 12 weeks.
This groundbreaking experiment is also another nail in the coffin of starvation mode:
Each participant lost weight steadily until the end of the study. The rate of weight loss slowed, of course, for the reasons already described, but weight loss never came to a complete halt.
So it's pretty safe to assume that with 1,500 kcal per day and many hours of moderate exercise per week, people still lose weight steadily ... for six months ... we have nothing to worry about.
So if metabolic damage and starvation mode can't make you stop losing weight, what can be responsible for a plateau?
The real reasons you stop losing weight
There are three reasons why you stop losing weight for no apparent reason:
- You are storing water
- You are building muscle
- You eat too much (and in most cases more than you think)
That's all.
Trust me.
Your metabolism is not as unique as a snowflake. Your body works the same way mine and everyone else's does. You just need to learn how your body is "tuned" and make sure you don't make any of the common weight loss mistakes.
The bottom line on metabolic damage and starvation mode
Metabolic damage and starvation mode are, for the most part, bogeymen.
Your metabolic rate may drop when you lose weight (although not necessarily), but if you know what you're doing, the effects of this will be negligible and quickly reversible with a short period of 'reverse dieting' once you've reached your goal.
Even if you've already done everything wrong to lose weight - you've cut calories too much, you're eating too little protein and you're doing far too much cardio - you still don't need to worry about this. Even the most extreme circumstances can only cause a small reduction in metabolic rate and this reduction will disappear naturally when you go back to eating normally.
Source: https://www.muscleforlife.com/metabolic-damage/
By Michael Matthews