Why Does Metabolic Adaptation Matter?

Metabolic Adaptation: maybe you’ve heard about it or read about it online. What is it? And why does it matter? 

Metabolic adaptation refers to our body's metabolism. 

Defining Metabolism

First, let's define metabolism. Metabolism refers to the chemical processes that allow life and normal functioning1. These processes include those that break down nutrients from our food and those that build and repair our body1. The body's metabolism also plays a major role in weight maintenance, gain, and loss. External factors that impact metabolism are calorie intake and exercise. When external factors change your metabolism, this is called metabolic adaptation.

There is research to show that metabolic adaptation occurs during periods of prolonged negative energy balance2. In other words, if you are in a calorie deficit, or consume fewer calories than your basal metabolic rate (BMR), also known as the baseline calories your body needs to function, for an extended period, your body then adapts to a new BMR. For example, Shelby’s BMR is 2100 calories per day, and she consumes only around 1800 calories. Shelby may have initially experienced a decline in her weight or her clothes fit differently and then she stopped seeing those changes. Her weight then plateaued, because her body had adapted to the new BMR of 1800 calories. Why does the body do this? The body adapts to the new BMR to continue to preserve energy and maintain fat and energy stores. Think of this as a survival mechanism, the body knows that it needs fuel to continue all of its important metabolic processes and it will hold onto any excess stored energy to conserve it for emergency use.

While research is still emerging on this topic, it is widely accepted that with a decrease or increase in weight, there is a decrease or increase in BMR meaning the overall energy needs to adapt. If you find yourself restricting calories or foods and feeling lethargic, tired, or not losing weight on a low amount of calories or low energy intake I encourage you to focus on fueling more and eating enough each day. 

It is always recommended to consume 3+ meals per day that are well balanced with a variety of foods from each food group; carbohydrates, fats, and protein. All foods fit and our bodies will be most efficient and serve us best when we treat them the best. This is why a weight-neutral and gentle approach to nutrition serves most people best, it allows room to fuel our bodies, listen to our needs, and to better support our overall bodily functions. 

1. https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/metabolism#:~:text=Metabolism%20refers%20to%20all%20the,build%20and%20repair%20our%20body.

2. Hall KD. Energy compensation and metabolic adaptation: "The Biggest Loser" study reinterpreted. Obesity (Silver Spring). 2022;30(1):11-13. doi:10.1002/oby.23308

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Written by Delayna

Hey, I'm Delayna!

I’m an RD-to-be, college cheer coach, yoga instructor, and food and fitness lover. As an intern at HSH, I hope you find this blog and the resources available with HSH supportive on your journey to your most nourished and happiest self!  Learn more about the HSH offerings here.