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WHAT is your Metabolism?? What is Metabolic Adaptation??

Most people have either a fixed mindset around metabolism or really don’t know what it is.⁣

⁣We’ve been told it is slow or broken when in reality it is adaptive or compensates to its environment…

The truth is, You don’t have a broken metabolism.⁣

You don’t have a damaged metabolism.⁣

Like every other human being – you have an ADAPTIVE metabolism.⁣

Our metabolism is a lot of things (malleable, complex, adaptive), but one thing’s for sure is it’s not a static or stagnant being.⁣ Hence when we lose weight or gain weight the amount of nutrients (calories/macros) we may need to consume changes with the adaptations we are experiencing.

When folks throw around terms like broken metabolism or metabolic damage what is actually tends to be more of a “compensation” or “adaptation” as opposed to actual damage (this is typically referred to as adaptive thermogenesis in human research). It’s also crucial to triple check accuracy of tracking and develop key baseline metrics on things like sleep and non exercise activity.⁣

If adaptation is in fact happening, what tends to drive this metabolic change that we see during a diet, or an attempt to live at a reduced bodyweight (compared to relative past), lies in our body’s adaptive physiology and neuroendocrine system.⁣

⁣So what does that mean??

Does losing weight slow down metabolism? Absolutely.

Does metabolism decrease more than expected? It depends!

Metabolic adaptation is the process by which the body alters how efficient it is at turning the food you eat into energy. It is an evolutionary biological process in response to starvation which when we look at it through the prism of our prehistoric ancestors, makes a lot of sense! If food was abundant this meant starvation was unlikely and therefore there was no need for the body to store calories as fat for later use.

In times of famine, it was essential for one’s metabolism to be extremely efficient and only use a minimal amount of calories to maintain biological homeostasis as the rest must be stored as fat for later use to prevent starvation.

From this understanding of metabolic adaptation in terms of starvation – we can apply this to dieting!

To understand metabolic adaptation, we must first understand the elements that effect it including TDEE (Total Daily Energy Expenditure) and its components.

TDEE (Total Daily Energy Expenditure), which is the total amount of calories burned in a day, is comprised of exercise activity thermogenesis (EAT), non-exercise activity thermogenesis (NEAT), thermic effect of food (TEF) and your resting metabolic rate (RMR). During phases of dieting, your TDEE changes. This is your body’s way of manipulating its role in energy conservation so if you have less calories available you will burn less and your body will prioritise its highest needs first – metabolic functions etc.
Remember that metabolic adaptation is a response to starvation, but in modern times, dieting is the closet we’ll ever get to famine. This is therefore why your body recognises this net decrease in calories from dieting and perceives it as starvation. When this occurs, your TDEE, BMR, NEAT and EAT decrease as your body becomes more calorically efficient. This is why an individual can maintain a caloric deficit for a week weeks, lose weight then plateau while eating the same amount of calories.
In the fitness industry, this type of phenomena has often been associated with the term ‘metabolic damage’ but the main difference between metabolic damage and adaptation is that “damage” suggests that there is an irreversible issue whereas adaptation indicates the body is making an adjustment. Despite what you may have heard – no, losing weight does not “damage” your metabolism!

The physiology of weight loss is complicated, but the best strategies for losing fat and keeping it off don’t have to be! Understanding what metabolic adaptation is can help us better understand how we can achieve better body composition results in the long-term whilst highlighting the importance of strategies such as diet-breaks, refeeds and the reverse dieting can help keep energy expenditure higher and thus make the dieting process easier!