When We Cause Metabolic Damage and How to Fix It

Why Athletes and Active Adults are Struggling

Metabolic damage, starvation mode, and weight loss resistance are interchangeable terms used to describe a slowed metabolism. Active adults and athletes are struggling with this real dilemma of not being able to lose weight. Regardless of how much exercise or dieting is done, body fat reduction seems to be impossible. 

The answer could be as simple as your food intake and exercise. The human body understands the nutrient value of food and importance of calories. It also knows when energy expenditure through exercise is increasing without proper fuel to support those demands. 

Our metabolism runs efficiently when energy input and output are in balance. Understanding metabolism will be an important step to fixing ​the metabolic damage. 

Understanding Metabolism

Mixed Race woman sitting on floor resting in gymnasium
BMR Uses Between 50-70% of Total Energy Expenditure. Peathegee Inc / Getty Images

Understanding how metabolism works in our body will be important to avoid metabolic damage. The following are a few basic terms to know regarding metabolism:

Resting metabolic rate (RMR): the rate our body burns energy (calories) at rest or in a non-exercise state. 

Basal metabolic rate (BMR): similar to RMR and often used interchangeably. BMR is the rate our body burns energy (calories) at rest or in a non-exercise state. BMR accounts for 50-70% of energy or calories required by the body daily. Females require approximately 1200-1400 calories and males 1400-1800 calories daily for optimal body functioning.

Activity energy expenditure (AEE): the rate of calories or energy the body uses during physical activity such as exercise. The rate will vary from 15% to as high as 50% based on sedentary lifestyle to ​the athlete. Typically, this figure represents approximately 20% of the energy our body uses.

Thermic effect of food (TEF): the rate of calories or energy required to digest, absorb and distribute nutrients in our body. TEF accounts for approximately 10 to 20% of daily total energy expenditure and varies per macronutrient. Protein requires the highest thermic energy expenditure at 20 to 30%. 

Metabolism Basics

Many factors can alter our metabolism including food intake and increased exercise. 

Research has indicated restrictive diets can slow down our metabolism which is a normal response. Additionally, many are unaware eating food causes a lowered energy output because calories are being burned during the digestive process. Consuming insufficient calories coupled with the thermic effect of food can leave our body in starvation mode.   

Increased exercise can also alter metabolism. If we're providing only enough calories to support our basal metabolic rate (BMR) and nothing for activity, this can have adverse effects on body function. Workouts are unable to be sustained without adequate fuel. Our metabolism is unable to shuttle sufficient energy to working muscles without enough calories.

Weight loss can also affect our metabolism. When we lose fat our body responds by trying to bring the body back into balance (homeostasis). Reducing body fat is a great thing, but not when it's done too quickly. It's recommended to allow time for our body to adjust to the reduction of energy or fat stores. Weight loss of one to no more than three pounds per week is suggested to avoid impairing our metabolism.

Losing weight too fast can adversely affect our metabolism. Our body struggles to regain balance and prevents further weight loss by decreasing thyroid levels and reducing nervous system output. We respond by restricting more calories and increasing exercise hoping to stimulate weight loss. Without realizing it, we disrupt normal thyroid and nervous system function even more. 

Stress hormones can alter our metabolism. When the body is undergoing chronic caloric restriction and additional exercise, it further adapts by increasing cortisol and reducing testosterone. Studies have shown these hormones to slow metabolism and impair our ability to lose weight. 

When trying to reduce body fat, we tend to combine several weight loss methods which can potentially cause metabolic damage. Our body will respond by using muscle for energy and holding onto fat stores to survive. In our journey of weight loss and ideal body fat, it requires a process of balance. 

We want to reduce fat and our body wants to make sure we have enough energy to run efficiently. The body is simply adjusting for survival and will do what it takes to make that happen. When we make a change with food intake or exercise, our body will respond with an adjustment and that's how it works.

How Metabolic Damage Begins

Putting on extra fat can leave us feeling anxious and wanting to lose it quickly. A determined attitude can get in the way of applying the right methods to reduce body fat. Our goal is quick weight loss and not worrying about metabolic function.

We start by reducing caloric intake consuming only half the calories of our typical daily diet. As a man this could mean instead of eating 3000 calories per day, now you are raking in a measly 1600 calories. The same is true for a woman eating 2200 calories per day and shaving it down to 1200 calories.

In order to blast fat fast, an hour of cardio per day is added to your already exhausting exercise program. The start of the program resulted in significant weight loss and stimulated an even more determined attitude.

Additional weight loss methods implemented over the following weeks failed to reap the same weight loss benefits. Welcome to the beginning of the big stall. 

Why is This Happening?

Fat has stopped shedding, the scale is not budging and pure frustration has set in. Why is this happening?

In a desperate attempt to fix the problem even more drastic measures are applied. The decision is made to cut out all carbohydrates and reduce fat intake to 25 grams per day (that’s only two handfuls of nuts).

The body responds to the adjustment by barely shedding any fat weight this time. Continued disappointment in the new strategy sends many to the gym adding once again an extra hour of cardio.

A few more weeks show nothing in fat loss and the body has stopped responding to weight loss efforts altogether. 

Can I Fix Metabolic Damage?

Once we have altered our metabolism to the point of creating metabolic damage, steps can be taken to get it back:

Resting our body will be important for metabolic recovery. Apply an eat less, exercise less approach for a few weeks. Walking and light weight training is recommended through this period. Having a discussion with your physician that also includes adrenal fatigue may be helpful. 

Once you start feeling better, have more energy and an improved mental game, slowly return to appropriate methods of weight loss

It will be important to think about fat loss as a process and become patient with your progress. Fat loss is not to be rushed and aiming for approximately one to no more than 2lbs per week as a healthy goal.

Slow weight loss reduces the risk of muscle atrophy (wasting) and allows your body to adjust slowly to applied changes.  

Begin by making minor changes to your caloric intake. Keep carbohydrates in your diet and don't overdo the cardio sessions. For every change or move you make, your body will respond with an action similar to playing a chess game. Cutting calories doesn't need to be combined with additional cardio all at once. Your metabolism will not be your friend doing too much too soon. Give your body a chance to adjust to reduced calories without the added stress of increased physical exercise.

Carbohydrates are also essential to keeping metabolism elevated by activating a fat-burning hormone (leptin). Increased leptin levels are indicated to improve energy output. Reducing and eliminating carbs lowers leptin levels and decreases their function.

Adequate fat intake is important for hormone function, especially testosterone. Testosterone helps to increase our metabolism and fat burning ability. Eliminating fat from our diet can cause impaired body function and is shown to increase fat stores. 

The Takeaway for a Healthy Metabolism

Be patient – One to no more than 2lbs of fat loss per week.

Apply one change at a time and allow your body to adapt.

Carbohydrates are essential for an elevated metabolism. They may be reduced but not eliminated.

Fat intake is important for hormone function (testosterone) and burning fat. Moderate amounts of fat will prevent starvation cues and promote metabolic function.

If cutting weight for a fitness competition, apply the same methods in reverse to put healthy weight back on, but don’t pack it on.

Maintain a healthy weight on and off competitive season and the same goes for active adults. This will keep your metabolism running like a clock. 

A second reminder to be patient. Remember your body knows what you're doing. 

 

Sources:

American Journal of Physiology, Low-fat diet alters intramuscular substrates and reduces lipolysis and fat oxidation during exercise, Edward F. Coyle et al., 3/1/01

Experimental Biology and Medicine, Peripheral Signals Conveying Metabolic Information to the Brain: Short-Term and Long-Term Regulation of Food Intake and Energy Homeostasis, Peter J. Havel, 12/01

Journal of the International Society of Sports Nutrition, Metabolic adaptation to weight loss: implications for the athlete, Trexler et al., 2014

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