Losing weight even with an under-active thyroid

Losing weight even with an under-active thyroid


Before I start, you must be diagnosed by a medical practitioner to know you have an under-active thyroid.  Having said that, many tests are not that accurate and what constitutes a diagnoses varies a lot. 

How much your BMR (basal metabolic rate) is affected will vary individually. If your thyroid has been removed, obviously you’ll have the biggest slowing – up to 40 percent reduction. 
If your thyroid is still functioning (even at less than ideal capacity) it may be more likely to be around 6 percent reduction in BMR (3-5).

Your BMR accounts for 50-80 percent of your overall calorie burn. The rest comes from exercise, digestion, fidgeting and daily movements. Which is good news. Your under-active thyroid might not make as much difference as you think.

The other good news is that all of these steps will work for you whether you actually have hypothyroidism or not.   

**If you are taking medication, please do not stop taking that unless you are working with your GP and he/she advises to do so.

Weight loss with hypothyroidism can be harder, which can make you want to give up all together. But reread the paragraphs above and try to look at this as more challenging but definitely doable.

There are things you can control that will definitely help.  All is not lost, you can still lose your excess body fat.  It just may take longer than you’d like.

In actual fact, the same methods that work for someone with normal thyroid function and someone with low function are the same, the rate of loss may be different.

No two people lose weight at the same rate anyway even if following the exact same plan, so keep that in mind.  

The other thing to remember is the stricter you are, the faster your fat loss will be – this is everyone no matter what health issues you do or do not have. 

However, it can be easy to think “why bother” or “it’s not going to work, so why even try?”  This is why I’m going to focus on your mindset and lifestyle first – and in fact, this is useful for everyone to do before you even try to focus on nutritional changes.

If you’ve followed me for any length of time, you’ll know that I believe will power is NOT the problem with trying to lose weight.   We do not have an infinite amount of will power, not matter who we are.  Daily decisions from what to wear to food choices and life decisions all wear away at our daily allowance of rational decision making ability.

Because losing body fat is probably going to take longer for you, we want to make a lot less decisions about it on a daily basis, so first things first:


The first thing I always get clients to do is to remove as many temptations as possible from wherever they’re hanging out on a daily basis.  

The second is to make good food choices as easy as possible.

Things like cleaning out your fridge, pantry and office space and stocking them with fresh vegetables/fruit, lots of herbs and spices and even making sure you have meal sized portions of healthy protein foods (chicken, fish, lean meats etc) in your freezer (freeze flat for fast defrosting) all mean that you’ll have good food readily available at any time.

Online shopping, or click and collect type services are fantastic because you are a lot less likely to purchase last minute ‘in case’ foods as snacks or be tempted by colourful displays at the end of every aisle.

Having healthy meals and snacks already made is also very helpful.  Whether that’s complete meals in containers (my favourite strategy is to make extra full meals at tea time that can be grabbed for lunch the next day – I call this ’next-overs’) or simple things like: 

  • taking a ziplock bag of cut up veggies in the car or to work if you find you snack in those places (the car is one of my downfalls) 
  • Not having big containers of trigger ‘healthy’ foods like nuts available
  • Portioning easy to overeat ‘healthy’ foods like greek yoghurt
  • Hard boiling eggs for a quick protein snack source
  • Having meals in the freezer
  • Making bulk recipes like healthy soups etc in the fridge

One thing that can be super hard is getting the rest of your family on board.  

If its kids, yep you do have to take control – on a side note, think about their long term health. Do you really want them searching for articles like this in the future?  

A partner can be harder to convince.  They may want their special snacks or drinks around, but if they can store them elsewhere or even lock them away, it can be helpful.


Have some ‘if this’, ‘then this’ plans in place. Here are some ideas:

  • If I miss my planned training class time, I’ll do a 20 minute workout at home
  • If I forget to take my packed lunch to work, I’ll go to the supermarket and get something healthy instead of take away.
  • If……………I’ll

Most people like to think that their usual excuses are isolated incidents and that these things only happen to them because their circumstances are different to everyone else’s.

But this is actually rarely the case. 

Hardly anything in your life happens that you couldn’t predict.

 It’s usually happened before (probably numerous times) you is highly likely to happen if you think about it.

  • Not hearing the alarm…….
  • Meetings running late…….
  • Kids sick………..
  • Boss asking you to work back………..
  • Traffic……………
  • And the list goes on.

These are not isolated incidents so you need an “if this happens, I’ll do that instead’ action plan.


This is important for everyone who wants to achieve a successful fat loss goal.  However, its even more important if your thyroid is not functioning properly.

I cannot stress this enough.  If you don’t reduce your stress levels, your fat loss will be even slower or even negligible.

How can you reduce your stress levels?

  • Get enough sleep.  This varies from person to person, but if you’re not regularly getting 8 hours, look here FIRST
  • Spend at least a few minutes every single day doing something totally relaxing (besides sleeping) like reading, sitting in the garden,  having a massage or meditating.  
  • Look at what you can change in your routine to make it less stressful.  There’s probably things you can change that you think you can’t (or you just don’t think you need to) that will make a difference.  For lots its as simple as being more organised so you’re not in a rush in the morning, or having healthy food ready to cook, asking someone else to pick up the shopping or help clean the house.  
  • Start a gratitude routine.  Something as simple as thinking of something that makes you happy, you’re thankful for or looking forward to each day can help.  Write them down and pop them into a box or jar for later
  • Go for a walk.  On this walk, you’re not allowed to time it, try to go a certain distance or record it in any way besides to say you went.  It should be relaxed – it’s not for fat burning.  Its to get you back into your parasympathetic nervous system.  Enjoy the scenery, take a friend or your kids/partner etc if its still going to be relaxing.
  • Avoid friends or family that add to your stress levels.  Obviously this isn’t going to be your immediate family if you live with them – no, you’ve got to sort those stressful times.  But if you talk to or catch up with people that suck the life out of you, you need to cut them – at least for a bit.  You can do this – I have.
  • Exercise regularly – do not punish yourself with training though.  Regular exercise is very beneficial, but not if it’s pushing you into further stress.  So daily is good -but not at such an intensity that it’s draining or for too long and it leaves you exhausted.  Find the balance. Too much increases those stress levels too.
  • Tune in when eating. Make it a habit to eat and just eat. No watching TV, scrolling social media or reading. Just eating and perhaps conversation with loved ones. This will help you to slow down eating – vital for good digestion and also to tune into your hunger and fullness cues better. 
  • Have healthy snacks available and ready. Prep and planning go a long way towards reducing stress levels. See how this is all related.
  • Have those ‘if this, then that’ plans ready

You honestly need to reduce your chronic stress levels if you want to lose body fat.  This is for everyone but especially those with extra challenges like a slow thyroid.

If you believe you’re doing all the right things and nothing is happening, stress reduction is the first place I’d look to change that.


There is no special diet for those with hypothyroidism.  The same type of changes that help anyone lose body fat apply. 

That is, more whole foods, less processed foods, enough protein, plenty of veggies, some fruit etc.  A focus on improving health also helps with fat loss.

That said, there is some evidence that you could try the following (which are also options for those with healthy thyroid function too)

Anti – Inflammatory Diet

While still sticking to the whole unprocessed food guidelines, you have a particular emphasis on avoiding foods that can cause inflammation such as:

  • refined grain foods – breads, pastries, biscuits cakes etc
  • fried foods – in particular those fried in vegetable oils
  • any soft drinks, flavoured waters etc
  • processed meat (and possibly reducing intake of red meat)
  • any vegetable fats – so margarine, seed oils etc
  • alcohol

Increase anti-inflammatory foods such as:

  • leafy greens 
  • EV olive oil for cooking (check labels, many contain vegetable oils as well)
  • fatty fish (wild caught – not farmed)
  • nuts – raw 
  • berries

The Autoimmune Diet

This is really a more strict version of the Anti-Inflammatory Diet.

Avoid foods mentioned above, but also foods that are common allergens such as:

  • eggs
  • legumes as well as grains
  • alcohol
  • dairy
  • seeds
  • nightshades – tomatoes, potatoes, capsicum, eggplants etc
  • sugar and artificial sweeteners
  • many food additives (which is easier if following a whole food diet)

Some studies show that symptoms of low thyroid can be improved, even though it does not reverse the condition. (6)

Elimination Diet

This is basically avoiding certain foods and then adding them back slowly one by one to see if they affect you at all.  

Foods that can cause sensitivities or intolerances are totally avoided for at least a few weeks .  

You need to avoid all of the possible ‘issue causing’ foods at once and then introduce them one at a time back into your diet. 

This takes time and careful planning and prep.  Often it can cause more stress so its best to do this with help from a professional.  The FODMAP diet is an example of an elimination diet.

I have some really good sources of information for Elimination Diets and can help you with this.  In fact it’s a tool we learnt a lot about when I was studying nutrition

Remember that it doesn’t ‘treat’ any illness but can help you to pinpoint foods that may be causing symptoms for you that could be or might not be related to your thyroid issues.

Elimination diets are tough – you basically need to eat a really plain diet to start and that can be hard for lots of people. 

You’ll also need lots of support at home, including those you live with being on board and at least avoiding foods you can’t have when you’re there if possible.

Special Thyroid Diets

You may google your issue and find lots of experts selling special diet programs and/or supplements.

Research does not support any special diet aside from the changes I’ve listed above. If you purchase these programs, you’ll probably find that the plan ends up to be pretty much what you’d do if you followed the basics in this article anyway.


I recommend that you treat any possible deficiencies by eating a varied diet based on mostly whole foods.  

When looking at this list, remember that these are just common deficiencies that you may not have and to look at adding the food sources rather than supplements if you can.

Also note that some of the sources of certain nutrients are on the avoid or cut down food lists above. So depending on what you’re choosing to do with your diet, you may not be eating some of the sources, but will rely on others.


In addition to helping the body make red blood cells, iron is essential in the production of thyroid-stimulating hormone (TSH). Up to 43 percent of people with hypothyroidism also have iron-deficiency anemia. (7,8)


Your thyroid gland can’t make enough thyroid hormones if it doesn’t get enough iodine. If you use iodised salt you’ll be right. Most of us use seasalt now (it’s trendier) or even none if we’re eating really clean.

So try adding a little iodized salt to your diet each day.

Food sources include plain yoghurt, low fat fish and eggs.


The thyroid needs selenium to use the iodine to create the hormones T3 and T4. A deficiency is quite rare (that doesn’t mean you can’t be low) but is more common in those with Crohns disease or who’ve had gastric bypass surgery.

Food sources include eggs, yoghurt, pork, beef, chicken and fish.


Deficiencies are usually found in vegans or strict vegetarians.

Food sources include fish and seafood, red meal and chicken. Some nuts such as cashews and almonds also contain zinc


Involved in the creation of thyroid hormones, you’ll find tyrosine in yoghurt, meats and fish and eggs.

Before you take any supplements, make sure you’re including the food sources above (if you do not have any intolerances or allergies) and if you’re going to supplement, use a good multi-mineral (check the labels) instead super dosing on any particular thing. 


There are some foods that can stop the thyroid from absorbing the nutrients it needs to work properly.

It’s important that you do not avoid some of these foods as they are some of the most nutrient dense foods we should be eating and have many health benefits including helping with fat loss.

These foods include cruciferous veggies like broccoli, bok choy and cauliflower, as well as peanuts, turnips and soy.

I would definitely include the first 3 in any fat loss diet and the simple way to fix the problem is to cook the foods. Heating deactivates most of the goitrogens in the foods.

Avoiding peanuts and soy is easy and something I’d recommend to most people trying to lose weight anyway.


The thing to remember if you are having trouble losing excess body fat is, are you following the plan at minimum 80-90% of the time.

Sometimes we forget that we actually do need to be quite strict to get results long term.

At first, you can make a few changes and the scale moves more quickly, but after that, you honestly do need to tighten up. And you need to do that consistently.

  • Are you managing stress levels – really?
  • Are you exercising regularly but not smashing yourself?
  • Are you getting enough quality sleep?
  • Are you eating mainly nutritious, unprocessed foods?
  • Are portion sizes small enough?
  • Are you getting enough quality protein?
  • Are you eating enough vegetables?
  • Are you avoiding alcohol and other calorie laden drinks?
  • Are you taking time out for relaxation?
  • Is your goal weight realistic?

Should you even have a goal weight?

A lot of the time we set a goal weight based on some time in the past, something we saw somewhere or on a friend or relatives current weight.

If you’ve hit a plateau and you really do have excess fat to lose still, it’s usually not a matter of will power or being ‘strong’ or tough enough.

It might be that you haven’t set up your environment for success or that you’re justifying those excuses instead of working out ways to work around them.

Stop relying on willpower – even those people you think are using strong willpower aren’t. Or if they are, they aren’t being as consistent as their social media highlights let on.

For some it might mean trying out different methods while sticking to the principles of healthy eating outlined above:

  • More (or less) exercise
  • Changing your exercise routine up 
  • Intermittent fasting (helpful sometimes in the short term)
  • Different meal timing
  • Adding more stress reduction or relaxation time
  • Or just finding more ways to be really consistent instead of on and off.
  • Even actually following a plan that works


The most important thing you can do is to take action. Whether you decide to follow this advice above, contact me or follow something totally different, the key is to get started.

Decide what you’re going to do today to move forward.

Researching, reading, feeling sorry for yourself or complaining will not get anything done. As per all my programs, you have to get started – TAKE ACTION!!!


For information on our training and transformation programs, please complete your details below and I’ll send you some details via email. 

You can hit reply to any of my emails and I will personally reply to you within 24 hours if you have specific questions.

Alternatively, you can email me directly here: jo@fitterfaster.net.au any time.


  1. Canaris GJ, Tape TG, Wigton RS. Thyroid disease awareness is associated with high rates of identifying subjects with previously undiagnosed thyroid dysfunction. BMC Public Health. 2013 Apr 16;13:351.
  2. Re: Bad medicine: thyroid disease. 2020 Mar 5 [cited 2020 Mar 5]; Available from: https://www.bmj.com/content/345/bmj.e7596/rr/619446
  3. Welcker J, Chastel O, Gabrielsen GW, Guillaumin J, Kitaysky AS, Speakman JR, et al. Thyroid hormones correlate with basal metabolic rate but not field metabolic rate in a wild bird species. PLoS One. 2013 Feb 20;8(2):e56229.
  4. Mullur R, Liu Y-Y, Brent GA. Thyroid hormone regulation of metabolism. Physiol Rev. 2014 Apr;94(2):355–82.
  5. Yavuz S, Salgado Nunez Del Prado S, Celi FS. Thyroid Hormone Action and Energy Expenditure. J Endocr Soc. 2019 Jul 1;3(7):1345–56.
  6. Abbott RD, Sadowski A, Alt AG. Efficacy of the Autoimmune Protocol Diet as Part of a Multi-disciplinary, Supported Lifestyle Intervention for Hashimoto’s Thyroiditis. Cureus. 2019 Apr 27;11(4):e4556.
  7. Soliman AT, De Sanctis V, Yassin M, Wagdy M, Soliman N. Chronic anemia and thyroid function. Acta Biomed. 2017 Apr 28;88(1):119–27.
  8. Erdogan M, Kösenli A, Ganidagli S, Kulaksizoglu M. Characteristics of anemia in subclinical and overt hypothyroid patients. Endocr J. 2012;59(3):213–20.

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