“Metabolic Damage”

  • by
Metabolic Damage

Last post I spoke about “starvation mode”.  If you missed it, you can read it HERE

Basically, I spoke about how “starvation mode” (at least the version most of us know it as) is a myth.

In this post I want to talk about a fairly similar topic: “metabolic damage”.

You may have heard this term thrown around lately, as it seems to be the latest fad within fitness circles.

What is metabolic damage?

So, the theory goes something like this…

You follow a calorie-controlled diet for a prolonged period of time.  You workout regularly and consistently (particularly doing a lot of cardio, too). Over the weeks and months you manage to drop body fat and maintain or even build muscle mass too.  But what happens next?

It appears that all of that dieting and training negatively impacted your basal metabolic rate (slowed your metabolism).  Your body starts burning less calories than it should. And this ultimately brings your fat loss to a halt.  It has “damaged” your metabolism, i.e. “metabolic damage”.  Now the only way to fix it is by following a super complicated far-out bunch of witchcraft type diet techniques.

Not true.

Is metabolic damage real?

No, metabolic damage is not real.  End of article.  Just kidding! Keep reading.

As discussed in my post on “starvation mode”, when you are in a prolonged calorie deficit, it is true that processes do take place in the body to prevent further weight loss.  But it won’t “stop” you from losing fat.  And there are some external factors at play too when dieting.

So, it is true that:

 – You naturally tend to feel more tired and move less – i.e. NEAT (non-exercise activity thermogenesis) levels decrease (fidgeting, pacing, walking, etc).

– Also, it is true that your metabolism begins to slow down after consistent dieting (this is adaptive thermogenesis), meaning your body will burn less calories while at rest.

What may be classed as external factors, are:

– TEF (thermic effect of food) levels decrease, probably because you’ll be eating less food due to dieting.  So, your body will burn less calories through the process of digestion.

– You will burn less calories during exercise, because your body adapts to become more efficient at carrying out exercise while saving energy.  Plus, it may very well be that you are not training as hard as you think you are, if energy levels are declining from dieting.

But no, your body does not enter a “mode” where it refuses to drop body fat!  Nor does your metabolism get damaged.

The Minnesota Experiment

I want to refresh your memories from my last post on “starvation mode” POST,and again mention the Minnesota Experiment.

You can read more details about this in my previous post. To summarise, an experiment was conducted on starvation.  The participants were genuinely starved (extremely low calories) and forced to perform hard physical activity every day for six months.  The findings of this dangerous study were that the participants lost 25% of their bodyweight on average.  And, despite being starved and worked to exhaustion, the participants’ only saw a fairly small reduction in their basal metabolic rate (metabolism).  Furthermore, this decrease in their basal metabolic rate was significantly remedied after twelve weeks of following a normal diet again.

The take home message: their bodies did not suffer metabolic damage.  They continued to lose weight over the duration of the experiment.  And their metabolisms pretty much returned to normal afterwards.  If this is what happened to these guys after six months of torturous conditions, do you really think it will be different for you? In comparison, your diet of a slight calorie deficit , with workouts a few times a week is a breeze!

And another metabolic damage study

Still not convinced?  OK, here’s another paper.  They concluded that “the theory of permanent, diet-induced metabolic slowing in non-obese individuals is not supported by the current literature”.

The rate of weight loss did slow down, but it never came to a stop.  And participants continued to lose weight for the duration of the study.

Zinchenko, Anastasia & Henselmans, Menno. (2016). Metabolic Damage: do Negative Metabolic Adaptations During Underfeeding Persist After Refeeding in Non-Obese Populations?. Medical Research Archives. 4. 10.18103/mra.v4i8.908.


Then why does it seem that fat loss stalls after prolonged dieting?

This question is actually very simple to answer.

  1. Fat loss tends NOT to be linear, especially after dieting for a little while.  This means that after a few weeks into a calorie-controlled diet, you may very well not see a pattern of regular fat loss each week.  You might lose 1lb one week, 2lbs the next week, no change for the next two weeks, and then 1lb the week after.  It’s not always linear!  You may think that your body is not dropping fat anymore, when in fact it still is. The process just may have become slower.
  • You may be gaining muscle mass whilst dropping body fat.  This is especially possible for those new to resistance training.  If you lose a lb of fat but gain a lb of muscle, then your body weight will not have changed.
  • You may be retaining water.  This can happen depending on:
  1. hydration levels,
  2. the time of day you weigh yourself,
  3. your stress (cortisol) levels,
  4. your menstrual cycle if you are female,
  5. or even due to how much food you have still in your digestive system.
  • The most likely solution – you are eating too much.  Even when you have the best of intentions in sticking to your diet, adherence becomes harder and harder over time.  Portion sizes slowly begin to creep up, whether you know it or not. The best fix for this is to weigh and log all of your food and drink.

OK, metabolic damage doesn’t exist.  But what should I do after I finish dieting so to prevent regaining fat?

The answer to this question is really simple: reverse dieting.  I talk more about reverse dieting in this post HERE from when I used reverse dieting myself after dieting.  To sum it up, it is exactly as the name implies.  It is the process of gradually increasing calories and / or decreasing exercise levels over a time period to give your metabolism time to adjust back to normal, without piling on body fat.

I hope you found this post useful.  Yes, your metabolism will slow down a little from dieting.  But you now know that metabolic damage simply just doesn’t exist, so is one less thing to worry about.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.