Why Your Metabolism is Slow (and What To Do About It)

Written By


Expert Reviewed By

Dr. Lauryn Lax, OTD, MS

Dr. Lauryn, OTD, MS is a doctor of occupational therapy, clinical nutritionists and functional medicine expert with 25 years of clinical and personal experience in healing from complex chronic health issues and helping others do the same.

Images 3 1 | Why Your Metabolism Is Slow (And What To Do About It)

Slow metabolism, Your Thyroid and Hypothyroidism

When it comes to the topic of metabolism, it seems like there is one of two camps.

Those who have a fast metabolism.

And those who have a slow metabolism.

Or, often translated:

  1. Those who have a hollow leg and can eat an entire pizza, whole chicken or graze all day long, and never gain an ounce of weight, or,
  2. Those who cant even look at a piece of pizza, or spoonful of almond butter for that matter, without packing on the pounds


Unfortunately, the latter (those deemed with a “slow metabolism”) seemingly make up the majority of our society—on the fast track to joining the 95% of obese Americans by 2035 if trends continue.

The solution?

  • Turn to Google for advice on curing a slow metabolism and the top results yielded will tell you to diet smarter,workout harder or try a certain fat burning supplement.
  • This popular magazine for instance claims you are making diet mistakes by not drinking caffeine, drinking room-temperature water and not eating enough fat free dairy (even though fat-free dairy is connected to hormonal imbalancesanother topic for another day).
  • Another top post tells you youve done 31 different things wrong to mess up your metabolism (shame on you!)  –blaming things like road rage, too much caffeine, air-conditioning and not eating fruit on your issues.
  • And still one more from the Mayo Clinic points the finger to again, eating too many caloriesand not working out enough (If you just tried harder, gosh darn it! Maybe your metabolism would speed up).

The jabs don’t stop there either.

  • Infomercials scream in your face about the jaw dropping results of body wraps, Beach Body shakes and meal delivery services.
  • Your trainer tells you to do more cardio or cut the carbs.
  • Your primary care physician or dietitian tells you to watch the fat and drink more low-fat dairy.
  • And if all else fails? Theres a cosmetic surgery for that (like tummy tucks and lipo).

A “slow metabolism” is obviously diet and will-power related, right? If you just had more self-control, tightened up your calories a bit more and hit the gym every day, then you obviously wouldn’t have this problem, right?

So what gives when you ARE doing “everything right” but that metabolism is stilllllll sluggish?!

Sigggghhhhh….You guess that you MUST be bound to be this way forever….

Buzzzzzzzz (wrong).

Often times there is more than meets the eye (and more than any diet prescription or workout routine can do for you).

Introducing: The thyroid.


The thyroid gland is the “mothership” organ of your body.

It controls how your body responds to other hormones, makes certain proteins, controls how fast your body uses energy, and it influences your body temperature, mood, and metabolic rate.

Your thyroid governs how quickly you “burn calories” and keeps your metabolism chugging along—explaining why your weight or metabolism can seem out of control when your thyroid is “out of whack.”

A sluggish thyroid (“hypothyroidism”) is directly responsible for a “sluggish metabolism” (regardless of whether or not you burned 300 calories in Spin class today).

And a sluggish thyroid is an OFTEN OVERLOOKED phenomenon by most general practitioners today—namely because the primary bio-markers for hypothyroidism are not tested on most general blood tests; and the signs and symptoms of hypothyroidism are often confused with your gym use frequency and  whether or not you are “staying strong” on Weight Watchers.

Ideally, when your thyroid is up to speed, you feel energetic, think clearly, your weight is easier to manage, your bowel movements are regular, your mood and libido are upbeat, you know when you are hungry and when you are full, you are not cold all the time, and you don’t have to fill in those brows of yours with a pencil.  On the other hand…

Common Signs & Symptoms of Hypothyroidism (low thyroid) include:

  • Low energy
  • Unexplained weight gain (especially fluid)
  • Cold all the time
  • Slow-thinking
  • Low mood
  • Constipation or infrequent bowel movements
  • Feeling sluggish

An estimated 1 in 10 people struggle with diagnosed hypothyroidism—with an additional estimated 60-percent of people remaining undiagnosed (and unaware that they have it).

In addition, women are 5-8 times more likely than men to struggle with a thyroid condition (perhaps answering the reason why more women seemingly struggle more with weight than men, in general). 

A Science Lesson

I won’t get too technical with you here, but it’s important to know what a “healthy thyroid looks like vs. a “sluggish thyroid”…and how it gets “sluggish” in the first place.

Healthy Thyroid

The whole process of thyroid hormone production and balance begins with TSH (thyroid-stimulating hormone).

Step 1: Your TSH talks to your thyroglobulin (protein) in the tissues of your thyroid to convert into T4 (Thyroxine hormone).

Step 2: T4 (inactive thyroid hormone) is created and then talks back to TSH which converts it into the “active” form of your thyroid hormones (T3).

Step 3: Once you have some T3 hormones in your system, these hormones are ready to flee the nest, and go out into the bloodstream to do balancing and metabolic things.  

Step 4: T3 escapes into the bloodstream and responsible for the proper function of virtually every type of cell in the human body (i.e. body temp regulation, appetite, stress regulation and more).

Ideally, if you have just the right amount of TSH, then you will have just the right amount of all your other hormones , meaning: All things are balanced, your metabolism is steady and you feel healthy and energetic.

In addition, when your body is happy, balanced (and neither overactive or hypoactive), your thyroid hormones are also happy (and you actually make less TSH because you don’t need as much).

However, when your thyroid hormones get thrown out of whack—it results in either too much or too little thyroid hormone produced (hypo or hyperthyroid) from the thyroid gland.

What throws it out of whack?

Chronic demands on the body (like stress, toxins like BPA, soy, cancer, food intolerance, gluten, poor gut health and digestion, nutrient deficiencies—especially Vitamin D), eventually stress out the thyroid…and it doesn’t know how to deal.

Enter: Hypothyroidism (too much TSH), or hyperthyroidism (low TSH)—as well as “off” reference ranges of T4, T3 and reverse T3 hormones.

The bottom line: All you need to realize today is that…your “slow” metabolism may not be a result from lack of willpower.  

Do I have a sluggish thyroid?

Thyroid dysfunction is ultimately diagnosed by a blood test; however signs and symptoms can be enough to speculate and at least consider the possibility of thyroid dysfunction.

That being said, it is far too easy to diagnose ourselves with or without conditions, based on Google’s reports (when we find ourselves awake at 3 a.m., seeking the answers to our most burning questions, like “Why do I have a slow metabolism?!”), and I highly recommend a “test don’t guess” philosophy under the guidance of a functional medicine or nutritional therapy practitioner.

Unfortunately while many conventional doctors may even try to help you…many do under-diagnose thyroid issues, secondary to UNDER-informed understanding.

  • For one, most conventional medical laboratory reference ranges are highly outdated and docs are unfamiliar with the newer guidelines with a narrower normalrange.
  • Many docs also believe that thyroid conditions are related to TSH aloneand if this number is normalthey consider all else must be normal (failing to look deeper into T3, T4, Reverse T3 and thyroid antibody ranges as well); or vice versa, TSH may be out of range, but if T3 and T4 seem fine then Reverse T3 and thyroid antibodies are not checked.
  • Lastly, to their credit, conventional medicine also often receives a lot of flack for overdiagnosingconditions and overprescribingmedications in general, so some docs may fear blamingyour sluggish metabolism on a thyroid issue, telling you to just eat less and move more to fix things.

So how do you really know if you have a sluggish thyroid or not (especially if it seems like your struggles with weight or metabolism have been the bane of your existence for years)?!

A thorough evaluation of TSH, T3, T4, Reverse T3 and thyroid antibodies via lab work, as well as taking some of these natural measures to get the ball to healing rolling (and, if anything, decreasing stress):


Survey says: Your thyroid is “off.”

Now what?

Here’s a hit list of common protocols for firing that baby back up:

  1. Food is medicine. Nutritional and lifestyle interventions should always be the first line of defense and an informed healthcare practitioner can help guide you in a non-diet mentality treatment and view of food as medicine. For instance, limiting goiter foods, namely in their raw form (broccoli, cauliflower, brussels sprouts, kale, turnips, mustard, cabbage, bok choy, soy) is recommended. These foods are linked to decreased thyroid function (But notice I said limitingnot eliminating).
  1. Heal your gut. In addition, thyroid issues are often related to other triggers, like gut health dysfunction. A functional medicine practitioner can assess your body as a whole, and customize an approach based on your body’s needs to help you address any underlying issues that triggered thyroid imbalance in the first place. Additional testing such as stool samples, organic acid testing and SIBO breath tasking can help further understand root causes for your thyroid imbalance. Probiotics, digestive enzymes, L-Glutamine, and of course, clean water, thorough food chewing and slowing down, and opting for organic/non-GMO or pesticide-laden meats and produce as much as possible are all lines of defense.
  1. Supplement Savvy. Don’t just go popping pills left and right. Your healthcare practitioner can give you an individualized protocol, in addition to guiding and directing you to the best food sources for any deficiencies you may have. Common supps and nutrients (from food) include :
  • Vitamin A (i.e. cod liver oil, raw carrots, dandelion greens, chicken liver)
  • Copper (Meat, poultry, eggs, nuts, seeds)
  • Zinc (approx. 20 mg/day)
  • Selenium (only if deficient and you have antibodies for thyroid hormones)- approx. 200 mcg/day
  • Iron (leafy greens, grass-fed meat)
  • Vitamin D (sunshine, supplemental)
  • Select herbs (like kanchanar guggulu and bladderwrack(
  1. 4. Medicine Mayhem. Prescription medication does not have to be your first line of defense, and often times thyroid issues will resolve with a little less stress, gut health and real food. However, if thyroid issues have been going on for a while (unbeknownst to you), sometimes the chronic stress of an underactive or overactive thyroid warrants necessity for biodentical hormones—in small doses—to get things back up to speed. (Consult with your practitioner)

Want to get to the bottom of your metabolism?

Connect with Dr. Lauryn for a free 30-minute consult to find out if Thrive is right for you.


Bonus Tip:

If you’ve had a blood test completed recently, here is a list of functional reference ranges to be aware of (and recognize that what may be considered “normal” by a 1960’s medical text book may not apply today):


Laboratory (old school) reference range: 0.45–4.5 µIU/mL

Functional (ideal) range: 0.5–2.0 µIU/mL

*If above 2.0-2.5, but below 4.5, considered “subclinical hypothyroidism

*If below 0.5, considered “hyperthyroidism”

T4 (Free)

Laboratory reference range: 0.82–1.77 ng/dL

Functional (ideal) reference range: 1.0–1.5 ng/dL

T3 (Free)

Laboratory reference range: 2.0–4.4 pg/mL

Functional (ideal) reference range: 2.5–4.0 pg/mL

Reverse T3 (not often looked at on labs, but a test that can indicate a hidden thyroid condition)

Laboratory reference range: 9.2–24.1 ng/dL

*Reverse T3 can interfere with the conversion of T4 to T3, making your hormones get “out of whack”

The bottom line? Don’t go it alone. If you suspect there’s more to your metabolic “issues” than just “diet and exercise” (and I would not advise deprivation or round 3 of P90X sweat sessions), consider what may be going on underneath the hood.

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