Metabolic adaptation is a biological response following weight loss in which the body decreases energy expenditure, improves its metabolic efficacy, and increases signals for energy intake as an apparent survival mechanism to regain or retain lost body mass (Martínez-Gómez & Roberts, 2021; Trexler et al., 2014).
Consequently, metabolic adaptions make continued weight loss more difficult while increasing the chances of weight regain, especially in those who are overweight or obese.
Metabolic adaptation can play a significant role in the long-term success of many weight loss journeys as body mass makes up the largest component of resting metabolic rate (RMR), and decreasing body mass inherently results in decreased RMR.
What Causes Metabolic Adaptation to Weight Loss?
The primary cause of metabolic adaptation to weight loss is losing weight too quickly. However, metabolic adaptation to weight loss is an inherently biological feature of the human body, so it can be difficult to fight against.
Since the body has a biological system in place to regain fat mass that is lost, it can be difficult to prevent “fat overshooting” and the regain of additional fat mass following periods of weight loss (Dulloo et al., 2015). Therefore, it is critical that anyone who is beginning a weight loss program be aware that repeated bouts of weight cycling (weight loss followed by weight gain) can produce more metabolic adaptions and additional “fat overshooting,” so it is important to make healthy lifestyle improvements that produce weight loss instead of just trying to lose large amounts of weight quickly through extreme dieting or other extreme measures.
By reducing the number of weight cycling bouts, individuals will have better chances for long-term body composition improvements.
How to Prevent Metabolic Adaptation to Weight Loss?
In order to combat metabolic adaptations to weight loss, exercise has been theorized as a solution to maintain fat-free mass and lean body mass, which are the most metabolically active components of total body mass.
However, some research has indicated that even the relative preservation of fat-free mass does not negate decreases in RMR caused by substantial body mass loss (Johannsen et al., 2012). However, exercise can play a role in reducing metabolic adaptation to weight loss (as I will explain below), and there are other options as well.
Lose Weight Slowly
As a primary way of combatting metabolic adaptation for long-term weight loss success, individuals should attempt to utilize the smallest energy deficit that promotes substantial weight loss. Large energy deficits will result in increased lean body mass losses and should be avoided in an effort to maintain or even increase lean body mass losses during long-term weight loss programs.
Personally, I suggest a goal of losing two pounds per week or less. Any more than this rate can have detrimental long-term effects. Diets that attempt to tell you to lose 20 pounds in two weeks or other irrational goals are more likely to promote metabolic adaptations to weight loss.
Eat a High Fiber Diet
For several reasons, a high fiber diet can also be useful for combatting metabolic adaptations to weight loss (Melby et al., 2017). High fiber meals are generally more time-consuming, promote satiety, and increase the production of short-chain fatty acids that play a role in improving the gut microbiota.
Do Resistance Training
There are many aspects of metabolic adaptation to weight loss and its potential for promoting weight regain, but I believe the role of physical activity in preventing weight regain despite metabolic adaptation is critical. In a study on contestants of “The Biggest Loser,” it was clear that significant long-term increases in physical activity played a key role in preventing weight regain and promoting additional weight loss or weight management (Hall, 2021).
Not only does physical activity promote lean body mass gains that offset some of the metabolic adaptations created by body mass loss, but it also offsets decreases in RMR and has an effect on appetite signaling feedback.
Weight training is especially important due to its ability to increase lean muscle mass and improve markers of general health.
Along with dieting to reduce caloric intake, developing a physical activity program is crucial for long-term weight loss success.
Take a CLA Supplement
Unlike the other suggestions above, this suggestion to prevent metabolic adaptation to weight loss has less scientific evidence to support it, but I theorize that it can play an important role. CLA suppresses lipogenesis (the creation of body fat) and reduces lipoprotein lipase production in body fat, which promotes the storage of body fat (Kennedy et al, 2010).
Animal models consistently demonstrate anti-weight gain and anti-obesity effects of CLA, although human studies are inconclusive, However, I believe CLA has enough promising research that it can be safely utilized to help prevent metabolic adaptation to weight loss.
If you would like to try a CLA supplement, I believe a good option is Sports Research Max Potency CLA:
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Concluding Thoughts – Metabolic Adaptations to Weight Loss
Metabolic adaptation to weight loss is a biological feature that helped with survival throughout our historical roots but plays a key role in preventing individuals from maintaining weight loss. Losing weight slowly, eating a fiber-rich diet, and weight training are evidence-based approaches to reducing metabolic adaptation to weight loss and preventing repeated weight cycling bouts that can lead to future health problems.