Is Your Metabolism to Blame?

Is a slow metabolism keeping you from losing weight? Can you do anything to speed it up? A closer look at what we can realistically do to change our metabolism. 

Monica Reinagel, MS, LD/N, CNS
4-minute read
Episode #435

If you are unhappy with your weight or frustrated by your inability to lose weight, you’ve probably wondered whether a slow metabolism may be to blame.

Your suspicions may have been confirmed by all the diets, programs, and products out there that claim to “fix” a slow metabolism. Let’s take a closer look at what factors have an impact—either positive or negative—on our metabolism and how big that effect might be.

First, let’s define some terms. In this context, metabolism refers to your resting metabolic rate (RMR). This is the amount of energy your body uses just to maintain basic biological functions like breathing, pumping blood, blinking, and maintaining your body temperature.

For a healthy adult, this is somewhere in the neighborhood of 1200 to 1600 calories per day. However, there are some things that can lower the number of calories your body burns in “maintenance” mode--or slow your metabolism

Things that decrease your metabolic rate

Losing weight. This strikes a lot of people as criminally unfair but the truth is that the smaller your body, the fewer calories it takes to maintain it. But the effect is greatly amplified when you lose weight quickly.

Restricting calories. Dramatically restricting calories for more than a few days can also affect your metabolismand that’s above and beyond the effect of any weight loss that this causes.

Losing muscle. Lean muscle tissue is more metabolically active than other tissues such as bone and fat. So when you lose muscle, your metabolism slows. Yet another problem with rapid weight loss is that you lose a lot of muscle tissue in addition to losing fat.

See also: How much fat can you lose?

Getting older. We also tend to lose muscle tissue as we get older, which leads to a slower metabolism. As a result, we generally need fewer calories as we age.

Low thyroid function. One of the many things the thyroid gland does is to regulate metabolism. If your thyroid gland is not producing enough thyroid hormone, your metabolism slows. You can have your thyroid function tested if you suspect that it is a factor. If it is low, your doctor will probably suggest replacement thyroid hormone, which can help.

How to Preserve your Metabolism

The best way to protect yourself against these metabolism-slowing factors is to avoid quick weight loss and extended fasting or very low calorie diets. If you are losing weight, take your time, and be sure to consume sufficient protein, which helps to prevent the loss of muscle during weight less.  And although there’s nothing you can do to avoid getting older, you can slow age related loss of muscle tissue by increasing your protein intake.

See: How to avoid age related muscle loss?

Can you Increase Your Metabolism?

Avoiding the things that can slow your metabolism down is one thing. But is there anything you can do to speed it up?


About the Author

Monica Reinagel, MS, LD/N, CNS

Monica Reinagel is a board-certified licensed nutritionist, author, and the creator of one of iTunes' most highly ranked health and fitness podcasts. Her advice is regularly featured on the TODAY show, Dr. Oz, NPR, and in the nation's leading newspapers, magazines, and websites. Do you have a nutrition question? Call the Nutrition Diva listener line at 443-961-6206. Your question could be featured on the show.