“Reset” your metabolism? NEAT trick, but not really.
I have begun to notice a trending topic in the fitness world. Let me re-phrase that. A new, exciting phenomenon has forced its way in front of my eyeballs on just about every social media outlet. You may have already seen a chiseled physique talking about “resetting these 3 hormones” or an ad for a product to “hack the female metabolism”. Ta-da, that’s the secret to weight loss! Easy-peasy. So how do you reset your hormones (and/or metabolism), you ask?
Great question. You can’t.
Your metabolism is not a game you can “reset” or cheat (up, down, left right, B, A, Start?). It is made up of several components. While it is not cheatable, per se, some components are modifiable.
The graphic below illustrates these components and their relative size to your total daily energy expenditure, which many refer to as the “metabolism”. (In reality, metabolism is a complex network of chemical changes which convert nutrients into energy and cellular building blocks). As you can see, exercise makes up just a tiny portion of your total daily energy expenditure, which is why many people will not see results from a demanding workout program if they do not make dietary changes in tandem. In fact, non-exercise activity thermogenesis (NEAT), or the calories burned from all activities other than purposeful exercise, uses a larger chunk of our daily energy than exercise. Activities like walking around the office, doing yard work, or even fidgeting at your desk. Neat!
Believe it or not, we spend a decent amount of energy simply eating, digesting, and processing the food we eat. This is called thermal effect of food (TEF). Remember when we thought celery had negative calories? (Just a myth).
The largest puzzle piece, basal metabolic rate (BMR) makes up about 70% of our total daily energy expenditure. These are the calories we burn at baseline simply from staying alive. Factors that affet BMR include body weight, height, fat-free mass, fat mass, age, sex, genetic factors, and certain hormones. Fat-mass, you ask?Yes! It takes energy to maintain fat. While increasing your fat mass may defeat the purpose of increasing your BMR, increasing fat-free mass (I.e., by increasing muscle mass through strength training) may be one way to increase your BMR (2). Will this lead to weight loss? Possibly, assuming you do not “compensate” by eating additional calories. A caloric deficit is still required for weight loss to occur.
So, can you “reset” your metabolism? Short answer: no. Is it possible to modify your total daily energy expenditure through lifestyle changes? Yes! Will that lead to automatic weight loss? No. While the idea of a metabolic “reboot” sounds new and exciting, it is another trend that this dietitian will be slam-dunking into the fad garbage can.
Sources:
Trexler E, Smith-Ryan A, Norton L. Metabolic adaptation to weight loss: Implications for the athlete. Journal of the International Society of Sports Nutrition 2014;11:7. doi: 10.1186/1550-2783-11-7.
Aristizabal, J. C., Freidenreich, D. J., Volk, B. M., Kupchak, B. R., Saenz, C., Maresh, C. M., Kraemer, W. J., & Volek, J. S. (2014). Effect of resistance training on resting metabolic rate and its estimation by a dual-energy X-ray absorptiometry metabolic map. European Journal of Clinical Nutrition, 69(7), 831–836. https://doi.org/10.1038/ejcn.2014.216
