News Flash: You (Probably) Don’t Have a Slow Metabolism

Shannon Miller

February 14, 2019

“I can’t lose weight because I have a slow metabolism.” We hear it all the time, and for some, this is very true. However, for a majority of the population, there are likely other factors in play. Why? As it turns out, it’s actually rare to have a substantially “slow” metabolism naturally. Falling victim to the “slow metabolism” assumption can be detrimental to results, which prompts an important discussion around just how powerful lifestyle modification can be in controlling metabolism.

Losing weight is very difficult for most people. Eating well and exercising regularly can be hard habits to solidify on a long-term basis. After diet and exercise, the next factor that’s usually discussed is metabolism: an underlying mechanism that can have a big say in body composition. By definition, metabolism is “the chemical changes in living cells by which energy is provided for vital processes and activities and new material is assimilated.” In simple terms, metabolism refers to how the body converts what you eat or drink into energy to function. Even at rest, the body uses energy from calories consumed or stored to maintain internal processes like breathing, repairing cells, digesting and circulating blood.

The number of calories the body burns in a day while at rest is called the basal metabolic rate (BMR) or resting metabolic rate (RMR). Everyone’s metabolism is unique to them and dependent on factors like age, sex, body composition/weight and activity level. In general, individuals with slower metabolisms will tend to have a harder time losing weight, while those with faster metabolisms will lose weight more easily. That said, the trouble comes when individuals surrender to a self-prescribed “slow” metabolism without understanding that they can have a say in their metabolic rate by incorporating healthy lifestyle modifications.

Image credit: Vegan Liftz

You’re (Likely) Above Average

It’s true that RMR differs for everyone, but each individual is not necessarily classified as either having a “slow” or “fast” metabolism. In fact, metabolism is measured as a range, and most people fall within the average to higher end, according to trends in Composition ID client observations. A common myth is that overweight individuals have lower metabolisms, which is not always true unless a medical condition in present. In general, the heavier you are, the more calories you burn to maintain function even at rest. It’s actually relatively rare to have a naturally “slow” metabolism when controlling for outside lifestyle factors. Why? Our bodies were designed to run efficiently off of what we consume. Unless a condition is present, metabolism can be largely impacted by lifestyle behaviors.

Reasons to Have a Significantly Slow Metabolism

There are certainly medically sound reasons why someone may have a very slow metabolism which can affect weight or impact results from a fitness and nutrition plan. Most notably, these include:

  • Thyroid Disorders (hypothyroidism): Hypothyroidism is a medical condition where the thyroid gland (located in the neck) does not produce enough thyroid hormone, which can lead to fatigue, depression, and weight gain. Only 12% of people will develop a thyroid condition (hyperthyroidism or hypothyroidism) over the course of their life. Most doctors will check thyroid function for patients struggling with weight, but many will agree that the amount of weight gain from an under-active thyroid is lower than expected (only 10lbs on average).
  • Hormone imbalances: As we age, production of sex hormones decreases (estrogen in women and testosterone in men). This can affect body composition by reducing muscle mass, which can slow the metabolism. Hormone replacement therapy can be affective in managing imbalances under a doctor’s supervision.
  • Cushing’s syndrome: Cushing syndrome is a disorder that occurs when the adrenal glands produce too much cortisol. Cortisol is a hormone that regulates insulin and helps control the breakdown of proteins, carbs and fats. Cushing’s syndrome can result in obesity, and specifically, an increase in fat mass around the face a neck due to excess cortisol circulating in the body.
  • Medications: Certain medications such as antidepressants, diabetic medications and steroids are commonly known to decrease metabolic rate and cause weight gain.

It’s important to talk to your doctor if you suspect anything seriously could be going on, but if you fall in the majority of people who are not affected by a hormonal condition or are on medications that can slow the metabolism, it’s helpful to understand the power you have over your own metabolic rate.

Controllable Factors that Affect Metabolism

The good news: you’re not destined to have a slow metabolism. There are several factors derived by lifestyle behaviors that can affect RMR.

  • Irregular eating habits: Consuming too little calories over time based on your specific needs can slow down the metabolism to hold onto fat. When one assumes they have a very slow metabolism and reduces their caloric intake (or exercises excessively) over a long period of time to compensate, it can further hinder weight loss results. By eating enough calories to prevent the body from resorting to “starvation mode” to function, metabolism should increase.
  • Physical inactivity: Remaining physically inactive is a sure-fire way to keep the metabolic rate down. Increasing physical activity can fire up the metabolism, especially by incorporating weight training. Adding weights helps to increase muscle mass and decrease body fat percentage. Since muscle burns more calories at rest than fat, building muscle can raise RMR.
  • Lack of sleep: Sleep is essential to restoring the body and a vital part of ensuring a healthy metabolism. Chronic sleep loss affects glucose regulation and can cause insulin resistance. An excess glucose in the body can mean extra storage of calories as fat and eventual weight gain. Other hormones that regulate metabolism, including cortisol, thyrotropin, leptin, and ghrelin are affected by lack of sleep which can have a negative impact on metabolism.  
  • Dehydration: Water is critical for cellular processes in the body, including metabolism. Proper hydration is linked to lipolysis (the breakdown of fats and other lipids) and a decrease in appetite.
  • Stress: Stress can wreak havoc on almost every system of the body. Stress releases cortisol which affects fat storage and cellular metabolism, and can increase appetite leading to overeating.

It’s important to know there are other reasons why your metabolism may be lagging and how you can increase RMR through lifestyle modifications such as increasing exercise (weight training), getting enough sleep, reducing stress and drinking more water. So yes, you may have a slower metabolism right now, but you have control over raising it – and keeping it running higher.

The best way to understand your own metabolism is to measure it through an RMR test. Data from a Composition ID RMR test provides information about where your metabolism falls on the “slow” to “high” range, as well as a projected number of calories your body burns each day at rest, and an estimate of calories burned from everyday activity. From there, a tailored nutrition and exercise plan can be designed that falls within the correct calorie range required to lose fat mass and maintain (or gain) muscle mass.

Interested in learning your RMR? Schedule an appointment with our team of experts.

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