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Do you feel tired or cold or think you’ve gained weight? Does your digestion seem a bit more “sluggish” lately?

Are you convinced your metabolism is slower?

Why does this happen? Why does a person’s metabolic rate slow down?

What Can Slow Your Metabolism?

Metabolism includes all the biochemical reactions in your body that use oxygen and nutrients to create energy. And a lot of factors play into how quickly or slowly your metabolism works, for example, your “metabolic rate.”

But don’t worry! We know that metabolic rate, which is measured in calories, isn’t as simple as the old adage “calories in calories out.” In fact, it’s so much more complicated that I’m only going to go over a few of the most common reasons your metabolism can slow down.

5 Common Reasons Why Metabolic Rates Can Slow Down:

  • Dieting
  • Low Thyroid Hormone Levels
  • Body Composition and Size
  • Activity Level
  • Lack of Good Sleep

We’ll briefly consider each one below, and I promise to give you better advice than just to “eat less and exercise more.”


When you lose weight, their metabolic rate can slow down. This happens because your body senses its fuel source (food) may be scarce, so it adapts. It does this by trying to continue with all the necessary life functions but now with less fuel.

While dieting can lead to a reduction in body fat, unfortunately, it can also lead to a reduction in muscle mass. And as you know, more muscle means faster resting metabolic rate.

If you’re dieting, it’s important to maintain muscle mass so you don’t negatively affect metabolism.

Tip: Make sure you’re eating enough nutritious food to fuel your body without overdoing it.

Related Article: Your Metabolism Can Help You Lose Weight

Low Thyroid Hormone Levels

Your thyroid is the master controller of your metabolism and when it produces fewer T3 & T4 hormones, your metabolism slows down. These two hormones tell the cells in your body when it should use more energy and become more metabolically active.

If your thyroid is functioning correctly, it should work to keep your metabolism just right. But several things can throw it off course like autoimmune diseases and mineral deficiencies (e.g., iodine or selenium) for example.

Tip: Check with your doctor about having your thyroid hormones tested.

Body Composition and Size

In general, a larger person will have a faster metabolic rate than a smaller person, because a larger body requires more energy for fuel than a smaller body. However, it’s rarely ever the best strategy to gain weight to increase metabolism.

We know that your muscles that actively move and do work require energy. And even your muscles at rest burn more calories than fat, hence the amount of energy your body uses depends in part on the amount of lean muscle mass you have.

Tip: Include weight training in your routine to help increase your muscle mass.

Which leads us to…

Activity Level

Aerobic exercise can temporarily increase your metabolic rate. You may notice when your muscles burn fuel to move and do “work” because your body begins to feel hotter.

Even little thing adds up. Using a standing desk rather than sitting all day, taking the stairs instead of the elevator, or walking a bit farther than you usually do can all contribute to more activity in your day.

Tip: Exercise regularly and incorporate movement into your day.

Click here to get a variety of workouts, workout plans and challenges you can use to help you in your fitness or weight loss journey. Most require only your own bodyweight. Some require dumbbells or resistance bands.

Related Article: Fast Workouts for Busy People

Lack of Good Sleep

You can find plenty of research that explains the influence sleep has on your metabolic rate. The general consensus is your body needs 7-9 hours of sleep every night.

But note, I said “good” sleep. You may be getting the right amount of shut-eye, however, the quality of your sleep is just as important. If you’re tossing and turning or waking frequently, your body may not be getting the rest it needs.

Tip: Create a routine that allows at least 7 hours of good sleep every night.

Related Article: Learn How To Get Better Sleep To Avoid Weight Gain

What About You?

Do you have tips on supporting your metabolism? Share with us in the comments. I’d love to know!

If you have more questions about metabolism, sign up for my Newsletter for tips, tricks and resources to help you look and feel your best ever.

emma lynn

Hi, I’m Emma Lynn

I’m a proud mother of two wonderful children and a wife to a loving, affectionate husband. I enjoy exercise – yoga (yes, I teach yoga as well), running, and going to different fitness classes from time to time.

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