Metabolism is one of those concepts that is easily misunderstood among dieters and fitness enthusiasts. (And even among fitness professionals too.) It’s an incredibly complex set of processes that researchers and the general public have tried to simplify to easily digestible concepts. However, in that translation a lot of misconceptions were born.
This article will set out to highlight some of these misconceptions. You’ll likely see some familiar beliefs. What follows are metabolism myths – debunked.
But first, what is metabolism?
Metabolism involves a variety of complex chemical processes that the body uses to sustain life. Your body is made of all types of different cells, and these chemical processes are how these cells interact with one another: writing DNA, breaking down the enzymes in your food, converting nutrients to usable or stored energy, and yes, contracting your muscles to create movement.
All of this work requires energy, and that energy comes from the food you eat. (Either directly from food or indirectly from stored body fat.) The calories you eat are simply the amount of energy available to be used by the body. (In fact, the term “calories” is a unit of energy.)
Since metabolism encompasses all the processes that burn calories, it makes sense that it is relevant for individuals interested in weight loss. Remember, in order for weight loss to occur, you have to burn more calories than you consume. Those calories get burned via your metabolism supplying energy to do all this work. To maximize your ability to lose weight, you’ll want to be able to optimize your ability to burn calories.
Metabolism Myth #1: Metabolism can’t be altered.
Many people come to believe that their metabolism is out of their control, especially with the release of articles like that in the New York Times discussing the unfortunate outcome of many “Biggest Loser” contestants. Fortunately, this idea of “genetic fate” isn’t completely true.
While prolonged weight loss can cause “metabolic adaptation” (the slowing of your metabolism to adjust to the new level of nutrient intake), regular strength training can actually increase your resting metabolic rate—the number of calories you burn at rest.[1,2,3,4]
This occurs because muscle is “metabolically active,” which means that muscle tissue requires the burning of extra calories to maintain itself. This extra energy needed for the maintenance (and growth) of muscle tissue can alter your metabolism. In other words, body fat lives rent-free on the body, but muscle pays rent on time.
Metabolism Myth #2: Small, frequent meals help stoke the “metabolic fire.”
There is a commonly held belief that small, frequent meals speed up metabolism. This belief was perpetuated by two factors: 1) The description of metabolism as the burning of energy. While this is true, it certainly doesn’t capture the essence of metabolism in its entirety. 2) Stemming from the idea of metabolism as the burning of energy, the metaphor of a campfire became frequently used to describe this process. (Often referred to as the “metabolic fire.”) Just like a campfire needs a constant and steady supply of wood to keep the flame alive, so too then did the body need a steady stream of calories to keep the metabolism flame alive.
While the metaphor is easy to understand, and the idea of frequent meals makes sense intuitively, This hasn’t been shown to have an actual effect. Research conducted on this subject found that eating only two meals a day, compared to three meals a day, had no effect on total energy expenditure throughout the day.[5,6] Your body simply will not burn more calories with more frequent meals, when calories are controlled.
Does this mean frequent meals are a waste of time? Not necessarily. In some individuals, more frequent meals may be able to help them better control total calorie consumption. (Which is very important for altering or maintaining bodyweight.)
In the end, the best meal schedule is one that integrates well into your lifestyle. For some this may be smaller meals spread throughout the day. For others this may include less frequent, but larger meals at key times.
Metabolism Myth #3: Eating late at night will slow your metabolism and force the calories to be turned into fat.
There is a pervasive fear that eating late at night causes an increase in body fat. Intuitively, this makes sense because while sleeping we aren’t being active, which means we aren’t burning those calories we’ve just eaten. Not burning calories = increase in body fat.
The reality, however, is a bit different. In fact, the majority of the calories you burn every day are the result of invisible metabolic processes in the body. The amount of energy you burn through daily activity is actually very small. So while it’s true that you are not exercising while you sleep, your body is still burning energy.
There are studies that show a correlation between late-night eating and weight gain. However, this weight gain is likely caused because these individuals are consuming excess calories as a result of their late-night eating, not because of its effect on their metabolism.[8,9] In fact, consuming a meal late in the evening has no difference on metabolism than a meal consumed during normal daytime hours.
In other words, eating late at night is likely to contribute to weight gain in two different ways: 1) You consume calories above the amount required for your needs, and 2) You make poorer food choices late at night as a result of mental exhaustion.
Both can easily lead to weight gain, but neither is a direct result of changes to your metabolism.
Metabolism Myth #4: Carbs make you gain fat.
Low-carbohydrate diets have become quite popular in recent years. (Although, historically they’ve really just looped back around, having first gained popularity a few decades ago.) Proponents of low-carb diets often attribute the rise in obesity rates to an increase in carbohydrate intake, namely sugar. This view argues that in order to effectively lose weight you should refrain from consuming any foods high in carbohydrates or sugar.
(This is also the first diet wave to convince people to avoid fruit because of it’s sugar content.)
Although excessive sugar intake has been linked to an increased risk of Type II diabetes and other preventable diseases, carbohydrates (including sugar) play an important role in your body. Carbs are the body’s primary source of energy, especially for the brain (which uses sugar as fuel). Sufficient carb intake also plays a role in how well you can perform in your workouts (the intensity at which you can exercise).
In fact, world-leading metabolism researcher Herman Pontzer, Ph.D., and author of the book, Burn, studied one of the last remaining hunter-gatherer tribes in Tanzania, the Hazda, and found that they suffered from none of the preventable diseases of the modern world despite having a diet consisting of mostly carbohydrates.
Dr. Pontzer put it well,
The Truth Shall Set You Free
Metabolism is a very complex process and is easily misinterpreted in the world of fitness. These misconceptions cause confusion and lead people to behave in ways that are not only unhelpful but sometimes contradictory to the outcomes they want to achieve. You’ve read about four of the most common of these misconceptions. The truth behind these misconceptions will help simplify your weight loss plan and lead to better results.
Let’s keep the conversation going. Subscribe to my email list for regular content sent to your inbox.