Is Your Metabolism Really Damaged from Dieting?

The term “Damaged Metabolism” is thrown around quite often in the diet and fitness internet sphere. The idea behind it is that by dieting or restricting for a period of time, your metabolism slows down and no longer function the way it is supposed to. A damaged metabolism is blamed for a variety of symptoms, the most notable being prone to weight gain. In essence, this concept is true, but the term “damaged” is somewhat misleading.

Why “Damaged” Is Not the Right Term

The word damaged creates the connotation that metabolism is actually harmed and no longer functions properly, however, this is not the case: slowing down is exactly what the metabolism is supposed to do given a limited number of calories.

Damaged would imply that the stimulus that caused the problem is already gone, yet the problem remains indefinitely. Likewise, in terms of dieting, a damaged metabolism would suggest that the metabolism is still slow despite no longer being in a caloric deficit.

Why It Seems Like Your Metabolism Is Damaged

For many former dieters and those in Ed recovery, this change in metabolism may appear permanent because they seem to gain weight even when eating at maintenance. The problem is that they are often calculating maintenance based on their former body weight rather than their new body weight set point.

Maintenance vs Body Weight Setpoint

Eating at maintenance is different than eating for your body weight set point: maintenance just means that the number of calories to stay at a certain weight. For instance, a female may be able to “maintain” and 12% body fat by eating 800 calories a day, but she’ll feel dead inside during the process. Conversely, your body weight setpoint is the body weight and fat mass that your body strives to maintain through your metabolic rate, hunger, energy expenditure, etc. In other words, it is your natural weight equilibrium. The setpoint is body weight that you would end up if you were to eat to complete satiety for a period of time, anywhere from a few weeks to several months.

Dieting Raises Your Body Weight Setpoint

Your body weight setpoint increases after a period of dieting because your body wants to make sure that it holds on to some more fat aka energy, just in case there is another famine in the near future.

The only way to recover your metabolism is to allow yourself to reach that new body weight set point. It is only once you reach this new set point and stay there for a little while that your body assumes that there is no longer a famine and that it should return to functioning normally.

Minnesota Starvation Experiment

Below is a chart from the Minnesota Starvation Experiment, which was the largest, most comprehensive study ever done on semi-starvation and caloric restriction. The chart portrays the body weight and body fat of the participants before dieting, during dieting, and during recovery.

You can see in the chart that by around R10 (ten weeks into recovery) they were back at their pre-dieting weight and body fat levels. They were recovered at that point then, right? Not exactly, if they would have stayed at this level, they would never have recovered their metabolism completely. For instance, they would still have constant craving, low libido, and poor digestion. In order for them to recover their metabolism, they had to eat to their satiety set point, which is the body weight set point in which you are no longer hungry. For most of them, this new body weight set point was obtained at about 140% more fat mass than before dieting.

Body Weight & Fat Mass Changes Before and After Caloric Restriction:

Minnesota starvation experiment body fat changes

(Keys, 1950)

The Good Things About Reaching Your Setpoint

While the possibility of gaining this much weight in recovery might scare many of you, there are many plus sides to reaching this new set point. When you finally reach this set point you will no longer have the symptoms associated with eating disorders and chronic dieting. No more bloating, no more craving, no more easy weight gain, and no more feeling tired all of the time. Unfortunately, a mistake that many make during recovery is that as soon as they get close to their setpoint, they get afraid of the amount of weight they are gaining and begin dieting again or eating at maintenance. It is not always easy to accept the necessary weight gain, but it is worth it to fix your health.

You Will Begin Losing Weight Once You Hit Your Setpoint

The good news is that this is also the point that your body determines that there is abundant food and that it therefore no longer needs to hold on to all of this energy in the form of fat. You can see that in the last part of the curve in the chart above, this is exactly what occurred in the test subjects. By 56 weeks into recovery, the men were back at their original body fat and weight.

What Causes This Spontaneous Weight Loss?

You may be wondering the mechanism behind this post-setpoint weight loss. Once your body is no longer concerned with starving, it will begin to make several metabolic adjustments in your favor. A few of these changes include lowering your hunger, raising your resting metabolic rate, and increasing your non-exercise activity thermogenesis (aka NEAT). NEAT is basically an increased proclivity to move caused by excess energy. This may take the form of any movement that is not for the purpose of exercise, such as fidgeting, pacing, or getting an urge to take a walk. What’s important about this weight loss is that you should not have to force yourself to eat less or move more, that is dieting. When you are truly at or above your setpoint, the weight loss will occur without you consciously striving to lose weight.

How Will You Know When You Reach Your Setpoint?

I need to mention here that you shouldn’t have a goal weight that you consider your body weight set point. This weight might be a 160% increase for some, and only a 15% increase for others. Rather than targeting a goal weight, use your hunger and symptoms as a guide. Eat as much as you want whenever you want and once you begin to lose interest in food, you have made it to your set point.

Most Important Takeaway

I’ll end my emphasizing this again because it’s very important: after a period of moderate to severe caloric restriction, returning to your previous weight is not enough to fix your metabolism because your previous weight is now below your new body weight set point. You must reach this new body weight set point for your metabolism to fully recover.