Today we are going to learn all about what a damaged metabolism looks like, what causes it, how to fix it and how to prevent it for the future.
You’ve probably heard the word “metabolism” a lot, especially if you struggle with weight loss. While there is some good information out there, there is also a lot of pseudoscience and claims based on poor evidence.
Luckily, there has been lots of research on metabolism and weight loss and we have a good understanding of how our diets affect our metabolism and how to use our diets to manipulate our metabolism to be more in our favor, whatever that may be.

What does metabolic damage mean?
Metabolic damage is not a scientific term, but is used to describe the decrease in energy expenditure due to weight loss and restrictive dieting. Another term for this is adaptive thermogenesis.
Here is an example of what metabolic damage might look like:
- January 2022: 150 lbs, burning 2400 calories per day
- April 2022: 140 lbs, burning 2100 calories per day
- August 2022: 130 lbs, burning 1800 calories per day
- December 2022: 120 lbs, burning 1500 calories per day
As restrictive dieting and weight loss continues, metabolism will drop. This is because your body is trying to conserve as much energy as possible and your body has less tissue to maintain (less fat and muscle mass).
The lowering of your metabolic rate is pretty much unavoidable. While there are some modifications you can make to prevent metabolic damage as much as possible, it’s very likely you will experience at least a slight decrease in metabolic rate.
This being said, metabolic damage is not permanent and can be reversed by modifying your diet and lifestyle. I know the term sounds pretty scary, but I assure you it’s nothing to fear. If anything, the more you understand it and work with it, the better.
How do you know if you have a damaged metabolism?
There are a few signs you can look out for to see if you are suffering from a damaged metabolism. While some are pretty obvious, others can be harder to spot. In general, it’s important to be in tune with your body and understand when things may be off.
The first sign is inability to lose weight even when you are still eating the same calorie deficit as you were your whole weight loss journey. This is a sign that your maintenance calories are now the same as what your calorie deficit once was.
For example, if your maintenance calories used to be 2000 calories, and you ate 1700 calories to be in a calorie deficit, then when your metabolism drops to only burning 1700 calories, you will stop losing weight, causing your weight to plateau.
Another sign might be a decrease in energy. Because your body senses you are restricting your caloric intake, it’s going to be as conservative with energy as possible. That means you will likely have less energy to exercise or perform other activities throughout the day.
That being said, you will likely experience a decrease in energy when you first start going into a caloric deficit. A good way to combat this is ensuring you don’t go into a large deficit. Try not to decrease your calories by more than 200-300 calories per day and avoid overexercising.



What causes a damaged metabolism?
There are several factors that contribute to a damaged metabolism. Remember, our bodies are sensitive and very adaptive to change. Therefore, when you make changes to your diet and lifestyle, your body will also make changes to ensure you can survive these changes.
The largest factor in metabolic damage is weight loss. When you lose weight, your body has less tissue (fat and muscle) to maintain, therefore it is burning less calories throughout the day compared to before you lost weight.
Along with this, when you lose weight, your body thinks you are going through a period of starvation, therefore it will conserve more energy so you won’t lose as much weight. While this isn’t beneficial in the times we live in now, this was extremely helpful when starvation and malnutrition were a common struggle.
Another factor is restrictive dieting. The main reason this contributes to damaged metabolism is because it leads to weight loss. The more restrictive the diet, the more weight loss and the more damage to your metabolism.
Will eating 1200 calories a day slow your metabolism?
When I first became interested in weight loss, I downloaded the app MyFitnessPal and set up calories at the lowest limit possible, 1200 calories. I assumed that eating the lowest amount of calories possible would lead to the fastest weight loss, which is what I desired at the time.
Not only was I unable to maintain this low calorie limit for an extended period of time, but I also gained the weight back (plus more) quite rapidly after returning to my normal diet.
To put it plainly, 1200 calories will absolutely slow your metabolism down. Even sedentary women are burning about 1800-2000 calories daily. If you only consume 1200 calories (the energy needs for a sedentary 4 year old by the way) then you are putting yourself in a 600-800 calorie deficit every single day.
While it’s very tempting to eat the lowest amount of calories as possible to get the results you want as fast as possible, it is not a good idea and can actually be quite dangerous. Good into a small deficit (ideally about 200-300 calories per day) will yield slower results, but will also lead to less metabolic damage and will be easier to sustain long term.
Overall, I do not recommend eating 1200 calories per day. I can’t imagine any scenario in which this would be beneficial.



Is “starvation mode” real?
Okay, let’s talk about starvation mode. This is the idea that your body will actually hold onto weight or gain more weight when you are eating in a caloric deficit.
Fortunately, this theory has been proven false. If it were true, no one would die of malnutrition and starvation. While your metabolism can decrease when losing weight, it’s impossible to gain or maintain weight in a caloric deficit.
I think where a lot of this confusion comes from is the fact that people don’t really understand what a calorie deficit is. By definition, when you are in a caloric deficit, you are eating less calories than you are burning.
You can’t accurately predict how many calories you are burning a day in an online calculator. The only way to know for sure how many calories you burn per day is to be in a metabolic ward, which is incredibly expensive. Along with this, your metabolism changes day to day.
If you think you burn 2000 calories a day, and are eating 1700 calories a day and not experiencing weight loss, you may think calorie deficits don’t work. In reality, it’s likely you are actually burning less calories than you think you are, which is why you aren’t losing weight.
To sum it up, it’s impossible to gain or maintain weight when you are in a caloric deficit. Therefore, starvation mode doesn’t exist.
Is metabolic damage permanent?
No! Metabolic damage is not permanent in any way shape or form. Your metabolism is constantly changing and shifting. In the same way it decreased in response to weight loss, it will increase in response to weight gain, simple as that.
Don’t be afraid that dieting and weight loss has ruined your metabolism forever. It hasn’t. There are steps you can take to restore your metabolism back to baseline.
This being said, I don’t recommend going on super low calorie diets (like 1200 calories per day), even if you are able to bounce back from it. The lower the deficit, the more metabolic damage, and the longer and harder it will be to return back to normal.
Instead, opt for smaller deficits that will be easier to recover from. If your metabolic rate drops from 2000 calories to 1800 calories, it will be easier to bring back up compared to 2000 calories to 1400 calories. So be prudent when attempting to lose weight!



How do you fix metabolic damage?
So once you’ve discovered that your metabolism has been damaged, how do you fix it? There are several ways you can improve your metabolism again, but to sum it all up, you need to start eating more.
Some people choose to take it very slow to minimise weight gain. This is often referred to as reverse dieting. As you slowly increase calories, your metabolism will also slowly increase, leading to weight maintenance and even weight loss for some people (if your metabolism increases faster than your calories).
But, this process is long and can be hard since it requires precise tracking and discipline. Another way to increase your metabolism is simply just eating more, without tracking. The more you eat and the more weight you gain, the faster your metabolism will grow.
If you have a history of eating disorders or malnutrition, I highly suggest working with a medical team when regaining weight. There is a small risk for refeeding syndrome, therefore it’s best to work with health professionals who know what they’re doing.
You can also increase your metabolism by gaining more lean mass in the form of muscle. Because muscle burns more calories than fat, a 130 pound person with a 15% body fat percentage will likely burn more calories at rest compared to a 130 pound person with a 30% body fat percentage.
That being said, if you want to gain muscle, you need to be eating more calories than you are burning. The only exceptions are those who are new to weight training or those who are coming back after a long period of time. If you aren’t in either of these calories, you will need to be eating a surplus of calories to gain muscle.
Whatever way you decide to do it, it’s important that you are eating more. There’s no way to increase metabolism without increasing your caloric intake.
How long does it take to reset your metabolism?
Honestly, I can’t tell you for sure. It depends on how much weight you gain, how much of a caloric surplus you are in and if you are incorporating weight training or not.
It also depends on what your goals are. Are you trying to maintain your weight at 2000 calories? 2400 calories? 2600 calories? It will be longer to reach your goal if it is higher, shorter if it is lower.
If you go all in and eat as much as you can to gain weight, you might come back to baseline in a month or two. If you take your time to reverse diet, it may take several months, up to a year.
In the end, choose a method that works best for you and your goals. I would recommend taking it slow if you want to minimize weight gain. But, if you want to return back to normal as soon as possible you can always take the fast route.



How do you prevent a damaged metabolism?
There are several things you can do to prevent metabolic damage in the first place. I highly recommend implementing these tips instead of damaging your metabolism and then trying to fix it.
First, avoid restrictive dieting and weight loss. If you want to prevent metabolic damage completely, you should avoid weight loss completely, simple as that. There is no way to 100% prevent metabolic damage caused from dieting. While it can be minimized, it can’t be avoided completely.
Second, implement weight training. By increasing your muscle mass, you are increasing your lean body mass and therefore increasing your metabolism. By going through periods of gaining muscle and losing fat, you can change your body composition. When your body has a lower fat percentage, you will be able to burn more calories while staying the same weight.
In the end, avoiding extreme weight loss and adding some weight training to your routine can do wonders for your metabolism. Not getting a damaged metabolism in the first place is always best!
If you struggle with yo yo dieting and binge eating, check out my online course and ebook. I go over every step you need to complete to overcome chronic dieting and stop binge eating for good. If you want some free tips, check out my guide below: