We could describe thyroid as the pace maker for your body. Every cell of the human body has Thyroid Hormone Receptors. The thyroid effectively regulates your metabolism and how many calories you’re burning.


Generally speaking people with Hyperthyroidism (fast thyroid) tend to be lean but their issue is being able to build or maintain muscle. While people with Hypothyroidism (sluggish thyroid) can often be found overweight and have no energy.


One of the functions of thyroid is generating body heat by burning fat. Therefore, if you are finding yourself always cold, this could be indication of poor thyroid function.


Other symptoms of Hypothyroidism:

–       Weight Gain

–       Depression

–       Reduced Quality of Life

–       Poor Cognitive Function & Memory

–       Muscle Weakness

–       Fatigue

–       Constipation

–       Increased long term risk of Cardiovascular Disease

–       Increased risk of Female Infertility

–       Increased Low-Density Lipoprotein Cholesterol (LDL)


From all of the above, thus far we can conclude, thyroid hormone and its function is pretty fucking important.


Research shows that people who eat a lot of calories, have faster thyroid. People that cut their calories, get slower thyroid. Again, thyroid regulates metabolism, therefore, energy (calories) in can actually determine energy (calories) out.




Example: Under 1400 Calories


People that consume inadequate calories and enter starvation mode, their metabolism shuts down and their capacity for weight loss and improved body composition is near non-existent. A common finding in people suffering from a resistance to weight loss I an elevated Reverse T3.


Reverse T3? WTF.


Yes, thyroid is a little more complicated than you may have thought of. This leads me to an issue likely to arise in your visit to the GP for a normal checkup. For standard blood work, what is often only checked is (TSH) Thyroid Stimulating Hormone. This test is checking how much hormone is in your blood and the TSH being produced by the pituitary gland in your brain. Problem is, if you’re suspecting thyroid issues, we need the full picture drawn up.


The blood tests required for an accurate diagnosis are:

–       TSH

–       Free T3

–       Free T4

–       Reverse T3 (rT3)

–       Thyroid Antibodies


Warning: You may find these specific tests are not bulk billed however most should be if you are in Australia.


Second issue is in interpreting results. For example, you might find the upper range of TSH being 4.3 and your result came back as 4.2 and therefore it is considered normal.


Normal = Average

Average = Unhealthy


We/you should be striving for optimal not normal, understand the difference.


Thyroid Explained


Thyroxine (T4) is the hormone that’s released from your thyroid (not TSH) and secretes into the blood stream.


Your body converts T4 to Triiodothyronine (T3) which is 7-8 times more effective that T4 as a fat burner and metabolism stimulator. From there, it goes to 3,5-Diiodo-L-Thyronine (T2) which is the most potent thermogenic in the mitochondria.


If you are lacking calories, if you are in starvation mode, if you have lots of dietary induced inflammation, lots of allergies, intolerances, stress, toxic load, or gut permeability, T4 can often convert to Reverse T3.




Reverse T3 (rT3) is a metabolite of T4.


If you make Reverse T3, it looks like T3 in the body. It binds into T3 receptors and tricks your body into thinking you’ve got heaps of T3. Reverse T3 has a very high affinity for the pituitary gland. So, what happens is your brain thinks thyroid is going awesome and it can see T3’s bound everywhere and as a result, decides to produce a little less TSH (Thyroid Stimulating Hormone) and the thyroid is going to slow down.


If you are only measuring TSH and T4 to assess thyroid function, then you are going to totally miss what’s actually happening with your metabolism. This is why we need to look at the full picture rT3. Reverse T3 has 1/100th of the fat burning potential of T4. Remember T3 is 7-8 times more powerful as a far burner. Therefore, if your T4 converts to Reverse T3, you could be down 7-800 times difference in your fat burning ability.


Reverse T3 has helped us through periods of history where famine and hibernation were relevant. But in more modern times, this necessity is no longer given the availability of food in the western world.


Though unfortunately, there is a saturation of irresponsible ‘health’ professionals with bad information fuelling the belief that move more, eat less as the answer. There are also greater levels of stress from lifestyle practices and chemical exposure from industry, all of which can be correlated to a rising commonality of gut health and digestive related issues now also being labelled as ‘normal’. Gut permeability often comes with vitamin and mineral deficiencies attached such as zinc and selenium both of which are crucial for positive thyroid function.


With all of this being said, I don’t believe Hypothyroidism is the cause for increased rates of obesity and weight loss resistance but it certainly has contribution. If you didn’t catch last week’s piece on Gut Microbiome, you should now click below as you will see how these two aspects of health intertwine with one another