Revealed: The connection between your thyroid and weight

Claire Millins

Have you ever tried a diet, but however many calories you don’t eat, or carbs you forgo, nothing seems to work? One reason may be your thyroid. Yes, I know, big eye rolls, and cries of “Oh, that’s a good excuse, it’s almost as good as the “I’m just big-boned” one.” However, did you know that your thyroid dictates your metabolism? Ergo, any imbalance or disease afflicting this area may cause you to have metabolic problems. This, in turn, can lead to drastic issues with your weight – you may either gain weight, lose weight, or even find that losing weight is harder than usual. Who knew?

Thyroid Imbalances

In an ideal world, everyone’s thyroid would work perfectly, producing the right amount of thyroid hormones to keep the body in cruise control. And normal levels make it possible for various bodily functions to continue as normal.

Unfortunately, however, we don’t live in an ideal world. And sometimes the thyroid produces too much or too little of the hormones. And, it’s this that can affect your weight.


The keyword here is “hypo”. This is when the body doesn’t get enough thyroid hormone, or the hormones don’t work effectively in the body. As a result, metabolism slows down.

When metabolism decreases, there is not enough fuel and building materials to sustain the body’s activities, so they also slow down.

Any excess energy is stored as fat, because it hasn’t been used or broken down, causing weight gain.

As well as weight gain, because cells are using less energy a snowball effect on other bodily functions occurs:

  • Less heat is produced
  • Sweat glands no longer need to keep the skin moist
  • The body becomes colder
  • The brain activity decreases, which makes it want to sleep
  • The heart beats slower


The keyword here is “hyper” is at the other end of the spectrum, an over-active thyroid produces more thyroid hormones than the body needs.

When hormone levels rise, the body’s activities also increase. As a result, the body needs more energy than it has. It uses the stores of fat and protein to convert into the energy it needs. As fat and protein stores are used when the thyroid is over-active, the body will generally undergo weight loss.

And, as with hypothyroidism, this overactivity has a knock-on effect on other bodily functions, but in the opposite way:

  • The body produces more heat
  • The body sweats more to cool down
  • The brain goes into overdrive, which can cause irritability and insomnia
  • The heart beats faster

What causes thyroid imbalance?

There are many reasons why your thyroid may be unbalanced.

It really could be anything from disease and surgery through to the weird and the wacky like the environment or eating too many of certain foodstuffs raw.

If you do feel your thyroid could be behind how you feel, any unexplained weight gain or loss, make an appointment with your medical practitioner to rule everything out.

The environment? Seriously?

Modern life sees us eating more and more processed (insert toxic) food. We are also more exposed to pollution, industrial waste, and heavy metals than ever before.

And since the thyroid produces hormones that manage metabolism, it stands that anything that affects your thyroid will also affect your metabolism.

A 2017 study on thyroid disrupting chemicals concluded that although the data set presented limitations for a conclusive result: “It is certain that industrial chemicals are impacting on the endocrine system in many ways and in different steps of the specific axis. Since a correct thyroid function is widely recognized to be crucial for several biological functions including those of the cardiovascular, osteo-muscular, cognitive, and immune systems, larger studies and more homogeneous and reliable data should be addressed as a priority. The data summarized in the current review are in line with the considerations of the European Union Commissioner for Health and Food Safety in the occasion of the accomplishment of the scientific criteria to identify endocrine disruptors in the field of plant protection products voted in July 2017 by the member States representatives. Once implemented, the recommendations of the European Commission will ensure that any active substance used in pesticides which is identified as an endocrine disruptor for people or animals can be assessed and withdrawn from the market, a fundamental step towards greater protection of citizens from harmful substances.”

Dieting and thyroid: Problem? What problem!

When it comes to losing weight, the problem is that most diet programs are focused on eating less and moving more. After all, it’s basic physics if you consume more energy than you use then that’s a red flag to weight gain. So, of course, the opposite must be true if you eat less energy but use more by moving more, then you should lose weight.

If only it were that simple! Cutting calories does help in some way, but eating too little moves the body into ‘hoard’ mode. This results in the metabolism slowing to compensate for the lack of energy available, making weight loss nigh on impossible.

What’s the answer?

The answer is to reduce calories without slowing down the metabolism.

But how do you do that?

Ideally, consult your medical practitioner or nutritionist, but it can come down to simple maths.

We are all individuals, which is why a blanket calorie-controlled diet, in general, will not work. You need to work out the right amount of calories you need to create a balanced diet.

How many calories do I need?

  1. Weigh yourself
  2. Multiply your weight in Kg by 30

Simple, isn’t it? (OK, if you only know your weight in stones and pounds, convert it to pounds only. Divide it by 2.2 to get your Kg equivalent and then multiply it by 30)

  • Divide those calories into as many meals and snacks as you generally have per day
  • Then try to keep your diet at a 40% protein, 25% fat, and 35% carbohydrate ratio

A word of warning

If you are really struggling with your weight loss, don’t let the snake-oil salesmen persuade you. You know, those ‘drop a dress size in a week’ and shake brigade merchants. It will not work!

This is because the real problem is those huge corporations that convince you to part with your hard-earned money, don’t actually take into consideration how your thyroid and metabolism may affect their weight loss program.

Golden Nugget

Did you know that iodine is the basis of the thyroid hormones? So, if you are having problems with your thyroid, maybe think about taking an iodine supplement. As always though, seek medical advice before taking any supplements.

Until next time darlings


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Posted By  : Claire Millins

Claire Millins

Claire Millins

Claire is a freelance writer and "blurbologist". She writes about health and wellness, fitness, travel and motorsport. Generally found where the fast cars are, Claire wears a lot of pink and also is a firm believer life should include more impromptu sing-alongs, dance routines and jazz hands 👐