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Think you know about metabolism? Chances are, your understanding varies greatly from reality. Throw aside the common excuses attached to metabolism and learn how to finally get your under control, once and for all.

8 Metabolism Myths & Facts

Discussing metabolism can be a sensitive subject for some, as most of its associations are related to weight. However, metabolism is more than "calories in, calories out" and deserves the chance to be further understood. From how it is controlled to assumptions on green tea dieting, learn the reality about metabolism myths and truths here!

8 Metabolism Myths & Facts

Claim #1: Metabolism is Controlled by the Thyroid Gland

The Truth: Yes, metabolism is mostly controlled by the thyroid, a small, butterfly-shaped gland that sits at the front of the neck and determines that rate at which the body breaks down calories from food into usable energy. But aside from the thyroid, weight, genetics, gender, body temperature, and the health of organ systems can also impact metabolism function and efficiency.

Claim #2: Thyroid Affects More Than Metabolism and Weight

The Truth: Yes, the thyroid does contribute to metabolic effectiveness and a consequential weight. And while the thyroid gland is primarily associated to metabolic regulation, it also serves additional functions, as it plays a role in hormone regulation and other body processes. Furthermore, if the thyroid is underactive (a condition known as hypothyroidism), which tends to lead to weight gain, additional symptoms include fatigue, depression, low sexual drive, hair loss, and dry skin. Hypothyroidism is detected through lab work and managed primarily with appropriate medication.

Claim #3: Metabolism Can Never Be Altered

The Truth: Although there are factors that cannot be modified, adaptations can help assist in a more efficient metabolism. Along with checking thyroid levels and addressing the need (or lack thereof) for medication, lifestyle changes plays a large part in changing metabolism. Reducing fat mass and increasing lean muscle through a well-balanced diet and regular exercise can boost metabolism.

Claim #4: Size Determines Your Metabolic Need

The Truth: Size and bodyweight plays a large role in metabolic needs. And while common associations suggest thinner people have a quicker metabolism, body composition (muscle versus fat tissues) mostly determines the rate at which energy is produced. For instance, a 200-pound individual containing mostly fat mass is not equivalent to someone the same weight with greater muscle and lean body mass, as muscle burns more calories. But as a general rule, the larger the size, the quicker the metabolism.

Claim #5: Men Have Faster Metabolisms Than Women

The Truth: Men do tend to have faster metabolisms than women, primarily related to lower body fat and more muscle mass. However, women are encouraged to have a higher body fat range for integral hormone production and childbearing. It is important to remember the recommendation is not a green light to disregard metabolism altogether, but an opportunity to take ownership of health through diet, regular exercise, stress management, and adequate sleep.

Claim #6: Metabolism Slows Down With Age

The Truth: Metabolism is shown to slow down even in the early to mid-20s, approximating a two percent decrease every 10 years after. The reduction is primarily related to a loss of muscle tissue and decline in activity levels as we age. Maintaining and preserving muscle mass through physical activity and a well-balanced diet can help counteract these effects of aging.

Claim #7: Eating Late at Night Slows Down Metabolism and Causes Weight Gain

The Truth: The eating late at night myth suggests that fourth meal slows down metabolism. But when it comes down to it, the body is still metabolizing that late night meal. And the timing of the meal is not necessarily the contributor to weight gain, but the content of it. Ultimately, the sum of calories and the quality of the meal may be causing weight gain...

Claim #8: Green Tea Dieting and Eating Spicy Foods Offers a Metabolic Boost and Results to Weight Loss

The Truth: Though it should be taken with a grain of salt, there is some truth to this claim. While green tea can a metabolic boost, it is not merely the glass of green tea that sheds weight, but other lifestyle factors chosen and implemented. Additionally, capsaicin found in spicy foods may suppress appetite and create a short-lived increase in body heat, but like green tea, it is important to not rely on it to shed off pounds!

Sydney Lappe's Photo
Written By Sydney Lappe, MS, RDN. Published on December 20, 2017. Updated on October 22, 2019.


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