Log in
Thyroid UK
93,507 members107,571 posts

Weight loss and hypothyroid: intermittent fasting?

Hi all,

I had my thyroid removed in 2007 after a history of Graves Disease, and since then have been taking 175mcg of thyroxine daily. My weight has steadily crept up over the years, in part because I will admit that I do like my food, but also, I find it very hard to lose weight, even when I try.

Someone was telling me about the benefits of intermittent fasting, where you only eat two meals a day, within an 8 hour window. The other 16 hours a day you fast (fluids only). There is a huge amount about it in the press at the moment too. It seems like something I could do and would be interested in.

However I was reading about it on one website where it was stated that this form of eating is not recommended for people with a history of thyroid problems. Has anyone here tried this type of diet, or is there any advice as to why I shouldn't do it with my existing thyroid issues?

Any advice much appreciated!

21 Replies

Absolute no no sorry. I will paste some links later on if that helps.

1 like

Thanks Daniel, I would be interested to see them. I don't want to do anything that is going to be bad for me!


I'd be interested to read your links too.

1 like

I tried this last Autumn. At first I felt I had more energy, then suddenly the symptoms of low cortisol re-emerged: hot, shaky, sweating and a rapid heart rate, all while standing.

I lost a bit of bulk, probably water, while fasting and regained it a few days after I stopped. Since then my immunity to infection has been worse than usual, but I don't know if there is a causal connection.

Dr Jason Fung seems to be the big noise on fasting, but he has little to say about its effects in hypothyroidism.



Thanks Hillwoman, I will give this a read x

1 like

Is your thyroid dose correct.

Post your TSH, FT4 and FT3 results for advice

Plus if you have them, vitamin D, folate, ferritin and B12

All thyroid tests should be done as early as possible in morning and fasting and don't take Levo in the 24 hours prior to test, delay and take straight after. This gives highest TSH, lowest FT4 and most consistent results

Dr Toft, past president of the British Thyroid Association and leading endocrinologist, states in Pulse Magazine,

"The appropriate dose of levothyroxine is that which restores euthyroidism and serum TSH to the lower part of the reference range - 0.2-0.5mU/l.

In this case, free thyroxine is likely to be in the upper part of its reference range or even slightly elevated – 18-22pmol/l.

Most patients will feel well in that circumstance. But some need a higher dose of levothyroxine to suppress serum TSH and then the serum-free T4 concentration will be elevated at around 24-28pmol/l.

This 'exogenous subclinical hyperthyroidism' is not dangerous as long as serum T3 is unequivocally normal – that is, serum total around T3 1.7nmol/l (reference range 1.0-2.2nmol/l)."

You can obtain a copy of the articles from Thyroid UK email print it and highlight question 6 to show your doctor

please email Dionne:

Prof Toft - article just published now saying T3 is likely essential for many. Note his views on how poorly patients are currently treated post RAI or thyroidectomy


1 like

Thank you for replying. I think I need to look into my results a bit more. At my last test my GP told me that I was on the high (meaning veering towards hyperthyroid) side of normal, which I prefer to the alternative. But I don't think they have looked at my T3 for some time.

I haven't read the article you have posted yet but have to agree about patients not being treated well post op. As soon as I had had my op I was discharged from my endocrinologist back to the GP, but having lived with thyroid problems for 20 years I don't think GPs have a wide enough understanding of the condition. When I had Graves disease I had been in remission for some time but knew as soon as the symptoms came back what was wrong with me. My GP at the time refused to give me a blood test telling me that he was the doctor and my symptoms were more likely to be depression. He also asked me if my then fiance was abusive towards me which had probably caused the depression! (he isn't)... it took me a battle and a second opinion to get the blood test which showed I was right! and a change of GP practice...)


TSH is largely irrelevant on Thyroid replacement. But is all most medics consider

Essential to test FT3 and FT4.

NHS won't spend 92p on FT3 test for vast majority of patients

So we have to test privately.

You are legally entitled to copies of your own blood test results.

You might be able to view online if you register for online access to your medical records. Ask receptionist.

All GP practices are supposed to offer this, in reality very few have blood test results available online.

If not then ask for print out of recent tests. Pick up in a day or two. They may make a nominal charge for paper.

1 like


I have followed this chap from the beginning and he sources much of his research from perhaps the worlds leading expert on the effect of diet on hormones ray peat. So solid stuff in my view.

Lots of changes IN:

Loads strong black coffee, salted OJ,potatos, carrots, celery, magnesium oil, zinc, selenium and B/D/c vits.


Alcohol, nuts,seeds,PUFA, (only fry with coconut pit/butter),gluten, dairy

3 extra items as a combination not really endorsed by anyone else specifically:

-black seed cumin oil capsules. - high strength

-250mcg kelp for iodine

-High protein fish and chicken diet for tyrosine

All I can say is the real world impact of these added to the above are astonishing imvho ie measured T3 conversion shoots up without needing to raise T4 - magic !

Good luck in whatever you choose to do.


Thanks Daniel, for these, I will give them a read - food for thought!


I'm still trying to get to the bottom of low carb high fat eating. I've read the forefront article in your link before, Daniel, and wondered if the LCHF diet I'd been following since early 2016 was a factor in my low T3 test I had done in September.

I'm reading up on it (as much as my brain fog will allow, that is!) and there is an interesting article in this link, by Dr Myhill. It's in the context of Chronic Fatigue and she is advocating a ketogenic diet, and goes on to discuss the thyroid. drmyhill.co.uk/wiki/Conduct...–_how_to_put_yourself_in_charge

"If the thyroid is going slow, then the adrenals gear up and vice versa. In the short term if adrenal hormones are used because thyroid hormones are not available then patients suffer “tired but wired” symptoms. This may be a particular problem if they are doing a ketogenic diet because their body will then use adrenal hormones to fat burn. They are biochemically in ketosis, but they suffer the symptom usually associated with low blood sugar (which in fact are adrenalin symptoms). This is called ketogenic hypoglycaemia. So, in this case, what we have here is Thyroid is going slow Adrenal hormones are used to compensate for this – there is a greater effect here if doing the ketogenic diet because thyroid hormones are used to burn fat and thyroid is going slow any way Person then suffers the symptoms of high adrenalin – which are the same symptoms as you suffer with low blood sugar (hypoglycaemia)"


SB, do you suffer from interrupted sleep patterns?

If so, all linked to cortisol and adrenals. The answer to all this is salted OJ drinks morning noon and night to coin a phrase.

There is a further article from the same man about this approach to fixing adrenals. If you have read this further article you will need no further encouragement.

I was stunned to find that something like OJ I had steered clear off for many years as I had not thought the sugar content made it that healthy would prove in these specific circumstances such a total “life saver “.

The joy of fixing the cortisol/adrenals you can get all the great benefits from plenty of strong black coffee and have a full night’s sleep.

I guess the reasons some other websites are so down on coffee is they are concerned their readers have not fixed their adrenals yet?


Hi Daniel, yes I do and yes my cortisol and adrenals are all over the shop. I'm seeing a functional nutrition therapist who got me tested and is addressing it.

I came across this guy's website quite early on in my thyroid journey and have read quite a bit on his site (that doesn't mean I've managed to take it all in cos my brain is definitely not understanding or retaining info as well as it used to, it's driving me mad!) I've dipped in and out of trying salted orange juice but am confused (permanent state right now LOL) between all the conflicting information about sorting sugar balance, not consuming sugars, etc. The link I posted by Dr Myhill seems to be taking the opposing stance, that low sugar/low carb is really important to thyroid function but also that you have to address the adrenals.

I'm really interested to know more about how it's helped you, as it's a different kettle of fish to talk to a real person as opposed to reading testimonials on a website that ultimately is also trying to sell products. I'd love to know more :)


The impact is totally life changing - every issue that you speak off can all be addressed.

Whatever you do or don’t do over OJ progress only motored when i took individual supplement for selenium and zinc and D. Just RDA of course in individual bottles.

I slept through every night up to 7 hours for the first time in decades - hence my first para is not hyperbole.

It have me confidence to crack on - next I took on kelp and plenty of salt on porridge each morning and gave up gluten and dairy. Again another step forward.

Then black cumin seed oil - and suddenly I am running 5k races.

If you find other helpers necessary then I am sure that is really positive - but all the information you need is all out there.

I am excited I have found one other follower for forefront as he seems imvho the most knowledgeable expert out there (ray peat aside).


Have you grasped why OJ is so vital and why carbs are so vital?


Hi Daniel, it took me ages to find this thread again! I knew I hadn't replied but was looking on my posts LOL.

I have very conflicting views to be honest on Tom Brimeyer. He doesn't appear to be highly regarded on here, plus his emails and website are so sales oriented.

But I am intrigued too by the advice he is giving!

I've followed a low carb diet since early 2016 for cardiovascular reasons. I struggle to think that drinking neat orange juice can be helpful.

I already take selenium and zinc and D, and salt (after years of avoiding it!). Kelp I am unsure of as I've read conflicting advice about it re the thyroid. I avoid gluten and very rarely eat dairy.

Black cumin seed oil - what's that about, then? The thought of being able to do a 5km run is attractive!

I'm intrigued to talk to someone who his approach has helped!


Tom meets resistance here because his website appears sales orientated.

If this is his business and source of income why this bothers everyone so much I struggle to grasp - I have paid for some of his materials just as I pay for blood tests and supplememts.

I place so much faith in his wisdom as he sources directly from dr Ray peat who many will accept is the leading researcher out there on health /diet.

He helped me make the connection to Ray’s materials perhaps the most important being the destructive role of PUFA and this in my view trumps by a mile the risk of all the other nutritional risks we are advised against eg gluten/dairy. Ray drinks milk by the gallon I have read so very much an alternative view !

If I was only allowed 2 things to “change your life “ for a thyroid sufferer it would be stop PUFA and drink OJ.

OJ converts to energy without stressing the liver so if you are someone with liver conversion issues then OJ helps with higher metabolism / sense of well being when carbs may make you sluggish.

Crikey, it works. Try a large plate of mashed potatoes and see how you feel 30 minutes after eating. Then the next day repeat and drink large glass OJ just after meal and compare notes. Ditto with sleeping well at night - higher blood sugar reduces cortisol levels and improves restful sleep.

This is a simple idea and I suppose it either works or it doesn’t.

Manybideas I have tried from other websites eg apple cider vinegar, bile supplements, acidopholus and a host of other ideas were a waste of time.

You do not say you take magnesium - this is absolutely essential I think.

Kelp I have enthused over - but I am minded to have a total break over for a month to see if this makes any difference. There is much resistance from many specialists so I will be careful to manage my risks and not go out on a limb.


Hi Daniel, sorry I have only just seen this. I didn't get a notification as you didn't reply directly on my last reply. I did try the salted orange juice and did notice a different for a couple of days. I'm still struggling with the idea of it though as it's taken me quite a long time to get my blood sugar levels stabilised and that was through avoiding anything that converts quickly to glucose.. eg orange juice! I think I'd feel more comfortable with some of his ideas if they had wider acceptance on here. But as you say, we don't like salesy stuff in the UK lol.

I don't touch PUFA. I read a lot about them when I was researching cholesterol. Devil's food!

I take magnesium citrate first thing and mid afternoon.

My off switch has detonated and I'm off to sleep. I'll have another read of what you've written tomorrow. Thanks :)


Good luck with all


My mum sent me some magnesium oil as she had some spare and I now accept her wisdom that this is an effective alternative to the tablets.

So I mix one tablet taking some oil as a combination that seems to get the best of both worlds.


You've reminded me that I have some mag crystals that I used to put in a water spray. Will dig them out again!


Daniel, I don't understand why you did not recommend the intermittent fasting for HEL123 as intermittent fasting has nothing to do with the low carb diet per se.

Yes, intermittent fasting is now mostly captained by the enthusiasts of low carb/high fat diets and keto diet... but its protocol is not designed for a low carb diet only. It is the short time window of eating that seems to work positively, not the content of the food eaten...

I have been quite skeptical about diets my entire life but I have now observed several of my friends and family members with hypothyroidism loose a good amount of weight and improve their blood tests results with the intermittent fasting. The same way I have seen a lot of people have fantastic results on low carb/high fat.

I have never seen any good results in a low fat diet/high carb diet. NEVER.

I never did any of this diets. I have difficulties dieting as I ate freely most of my life as I had hyperthyroidism my entire life and I was always very thin even eating as much as I wanted. (yes, I was one of those).

After I almost died of untreated/undiagnosed Graves and after I was forced to kill my over active thyroid, I now live with hypothyroidism. Everyday I struggle to keep a healthy weight. I am very tempted to try the IF... but there is not much about IF around here though...

1 like

You may also like...