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Your metabolism may not be to blame

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What you don't know is weighing you down

Chances are good you’ve heard someone blame their weight loss struggles on their metabolism. You may even think a slow metabolism is affecting your weight loss goals. However, slow metabolism is rare and studies show that, while normal metabolism is linked to weight, it doesn’t have a significant impact on weight loss or gain. So, how did metabolism get such a bad reputation as a weight loss villain?

Understanding what metabolism is and does

Metabolism is the process of your body converting calories to energy. It includes all the processes that allow you to function, including: breathing, circulating blood, controlling temperature, contracting muscles, digesting food, eliminating waste, building new cells, controlling brain and nerve function and more.

“Your body relies on calories from what you consume to operate. Metabolism is the process of your body converting — let’s say a peanut butter and jelly sandwich —into the energy it needs to complete all the little, behind-the-scenes operations that let you exist,” said David Lee, MD, of Novant Health Lewisville Family Medicine.

“With all of the calories your metabolism burns, it makes sense for people to blame metabolism when they’re not burning enough calories,” Dr. Lee said. “But there’s more to it than that.”

Metabolism and weight

When most people talk about their metabolism, they’re referring to basal metabolic rate, which is the number of calories your body needs in order to carry out its basic functions. The basal metabolic rate can be affected by factors such as your body size and composition, your sex and your age. Larger people, whether overweight or more muscular, require more energy and calories, even at rest. The male build typically is composed of more muscle and less fat than the female build, so men usually burn more calories than women. As you age, the amount of muscle on your body tends to decrease, meaning you burn fewer calories.

No matter your body composition, your basal metabolic rate accounts for about 70 percent of the calories you burn every day. The remaining 30 percent is burned through physical activity and food processing.

“Because metabolism is an internal process, tailored by your body for your body, it typically burns exactly the number of calories your body needs to operate. It operates as fast or as slow as your body needs it to,” Dr. Lee said. “Barring certain medical conditions that slow metabolism, such as Cushing syndrome or hypothyroidism, consuming more calories than your body burns is usually the culprit behind weight struggles.”

How to know if you really do have a slower metabolism

Cushing syndrome and hypothyroidism are real conditions that slow your metabolic rate, causing your body to burn fewer calories than it should.

Cushing syndrome — Sometimes called hypercortisolism, Cushing syndrome is caused when your body is exposed to too much of the hormone cortisol over a long period of time. The most common cause is extended use of oral corticosteroid medication, but it can also be caused by your body producing too much of its own cortisol. Common symptoms are progressive weight gain and fatty tissue deposits, slowed healing of cuts and scratches, acne, thicker or more visible body and facial hair and fatigue. Diagnosing Cushing syndrome can take multiple visits with your doctor to review medical history, outline current symptoms and rule out other conditions. With treatment, the symptoms can be managed.

Hypothyroidism — Hypothyroidism occurs when the thyroid gland does not produce enough thyroid hormone. The most common cause is thyroid gland swelling or damage, but it can also be caused by certain medications, congenital defects, surgical removal of the thyroid gland and radiation treatments of head and neck cancers. Because many of the symptoms are physical — pale or dry skin, thin or brittle hair and fingernails, weight gain and increased sensitivity to cold, to name a few — a physical exam is the starting point for diagnosis. If you or your doctor suspects hypothyroidism, a simple blood test can measure your thyroid levels. Treatments primarily aim to replace missing thyroid hormone.

Dr. Lee advises discussing any metabolism concerns with your doctor. In addition to being able to check your metabolism and assess your risk for the rare conditions that can affect metabolism, your doctor can help establish a plan of healthy lifestyle changes that will assist with weight loss, regardless of your metabolism rate.

If it’s not metabolism, why can’t I lose weight?

“If you don’t have a medical condition slowing your metabolism but still struggle with weight loss, it may be time to take a closer look at how you consume and use calories,” Dr. Lee said.

The factors most likely to contribute to weight gain (or that make it more difficult to lose weight) include:

  • Consuming too many calories
  • Not getting enough exercise
  • Genetics
  • Medications
  • Unhealthy habits, such as skipping breakfast or not getting enough sleep

“If we are able to rule out medical causes for a lowered metabolism, we can shift focus to the weight loss factors we can control, such as diet and exercise,” Dr. Lee said. “It’s going to take time, and a lot of baby steps, but by reducing your calorie intake and committing to some form of regular activity, you can break free from the metabolism myth.”