A few extra kilos creeping on during your 40s is a common experience for women. But believe it or not, weight gain in perimenopause is not just ‘getting old’! In most cases, it comes back to the delicate balance of hormones – particularly your sex hormones and thyroid hormones.

What is the thyroid?

Your thyroid gland is a butterfly-shaped gland in the neck. It makes two hormones that are essential for energy and metabolism – thyroxine (T4) and triiodothyronine (T3).

Through these hormones, your thyroid controls all of the processes of the body needed to sustain our life by converting food to energy, to make sure each and every one of our cells can do the job it was created for. This includes how quickly (or slowly) your body utilises energy. In fact, your thyroid function is one way that the old ‘calories in vs calories out’ notion goes out the window, because it can throw the energy balance right off.

Weight gain in perimenopause and the thyroid – what’s the link?

Thyroid dysfunction and disease risk increases with age, particularly for women. If you’re 40+, you have a 1 in 10 chance of something going wrong with your thyroid gland!

As with all things perimenopause, this comes back to your sex hormone shifts. The lowering progesterone levels means less of the active thyroid hormone (T3) is available. Lower progesterone can also mean a less regulated immune system, which can leave the door open for an autoimmune condition like Hashimoto’s to develop.

Symptoms of thyroid dysfunction

Although weight gain is one of the most common problems my clients come to me for, it’s rarely the first sign of a thyroid gone wrong. In fact, many of the symptoms overlap with the things we just accept as part of ‘getting older’ or ‘being a mum’ or ‘doing it all’. Think:

  • Fatigue
  • Brain fog
  • Low motivation
  • Lowered ability to handle stress
  • Sluggish bowels (constipation)
  • Depression and anxiety
  • Hair thinning
  • Dry skin
  • Joint pain
  • General aches and pains
  • Heavy/irregular periods
  • Insulin resistance
  • High cholesterol
  • Hot flushes

Is any of this sounding familiar yet? Of course, there is a big overlap between thyroid issues and hormone imbalances during perimenopause. In many cases, there is an overlap of both that needs to be addressed.

But my thyroid levels are normal?

Yes, I’ve heard this one a million times before! Unfortunately, most GPs will not test the full thyroid panel – only Thyroid Stimulating Hormone, or TSH.

The interesting thing about TSH is that it’s not even a thyroid hormone – it’s a hormone your brain produces to stimulate the thyroid to do its job. So although it can give us a warning of frank uncontrolled thyroid disease, it won’t pick up every case.

For a true understanding of the thyroid, you want:

  • TSH – low indicates overactive thyroid, high indicates underactive
  • T4
  • T3 (this is important, as it tells us how much ACTIVE hormone is doing its thing in your body!)
  • Reverse T3 – this is how your body reduces T3 and slows the body down to protect you. It’s often high when you are under stress
  • Thyroid antibodies – these signal autoimmune thyroid disease. You can have normal levels of the other hormones early on, but the earlier we spot thyroid antibodies, the more we can do to prevent further damage to the thyroid

Unfortunately, Medicare doesn’t cover all of these tests. Reverse T3 is always an out-of-pocket cost, and the others will only be covered if you already have a TSH out of range.

I don’t want to rant at you too much longer on blood tests, but I do want to remind you that ‘within range’ doesn’t always mean ‘optimal for you’. The current range of normal TSH in Australia is 0.5-4mIU/L. But research suggests that it should be more along the lines of 0.45-2.5. Personally, I like my clients to sit around 1-2.

Can you have normal thyroid levels and still have a dysfunctional thyroid? Absolutely.

You can have subclinical thyroid disease, particularly in the early stages of Hashimoto’s and Graves’ disease. There could be factors that are keeping your TSH low, such as inflammation, chronic stress and some medications. Then you can also have cellular hypothyroidism, which is when your cells are not utilising enough thyroid hormone for what they need to do (kind of like insulin resistance).

So weight gain in perimenopause – what’s the consensus?

If your weight has been climbing since you hit your 40s, please know that it’s not laziness, lack of motivation or self-control. There are very real metabolic processes going on that make it much harder to maintain your weight during this time.

There’s a very high chance that your sex hormones progesterone, oestrogen and testosterone are playing a role. But there is also a 10% chance that your thyroid is also involved (and honestly, I think that statistic is on the low side, given the amount of subclinical hypothyroidism out there!)

Weight gain in perimenopause is common, but not inevitable. You don’t just have to put up with getting heavier, sadder, exhausted and overwhelmed. The changes that occur can be addressed using simple tools such as diet, lifestyle, movement and sleep.

Do you suspect your thyroid is playing a role in your weight gain? Tired of doctors not taking your symptoms seriously?

Book in for a free discovery call today, and we can explore how I can help you to support and nourish yourself – mind, body and spirit.