5:2 and hypothyroidism

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5:2 and hypothyroidism

This topic contains 11 replies, has 6 voices, and was last updated by  Minka 7 years, 7 months ago.

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  • I previously followed the 5:2 diet and found I lost weight quite quickly, don’t ask me why I didn’t stick to it!!!! Anyway approximately 1 year ago I was told I had an underactive thyroid and was started on levothyroxine,. At first nothing filled me I couldn’t stop eating – not good. That has calmed down now and I have been following the 5:2 diet but I’m not having any success, I don’t know what to do, it’s so depressing, I need to lose 2 stone and it’s just not coming off. Anyone else found this please and did you find a way round it?

    Any help or suggestions gratefully received. Thank you

    Hi janeandmoses, sorry to hear you have hypothyroidism. I was diagnosed 7 years ago so have been on levothyroxine since. I gained weight before I was diagnosed and again when my doc dropped the dose down last year. I’m now back in balance and have found the 5:2 has worked really well for me. I started in Jan this year with a 12 kg target to lose which I achieved over 4 1/2 months.

    You don’t say how long you’ve been on treatment nor how long you’ve been trying the 5:2. Have you been on medication long enough to build up the blood levels? I was in a right mess when diagnosed so it took me around 4 months to normalise before I could think about tackling my excess weight.

    In my experience there should be no reason the diet would not work if you are strict about what you eat on the non-fast days and don’t exceed your TDEE.

    Sadly I’m currently recovering from a severed Achilles’ tendon so have suspended the 5:2 regime until I’m fit but with a healthy diet on 7 days I’ve still lost more weight. That could be muscle though as I’m wasting away!!f

    Hi thanks so much for replying. I have only been on the 5:2 (this time) for 2 and a bit weeks, it’s just that when I did it before I had a reasonable weight loss the first couple of weeks (I know its only water, but it strengthens your resolove) and best of all I felt thinner which in turn spurs you on. I have been on Levo for 12 months and at my last blood test the levels were right. Funningly enough, today, I feel a bit thinner so hopefully the weight will start to come off. I may make and appt with Dr and see if they will do another blood test to make sure my levels are still ok. I feel ok though. Perhaps I should be more strict with my TDEE. Your weight loss result is very impressive, well done you I have 28lbs to lose, it doesn’t sound that much, but believe me its clinging on for dear life.

    I’d like to keep in touch with you if you don’s mind, it’s always helpful to have someone to chat to and ask questions. Let me know how you are getting on and I hope your achilles tendon heals quickly and is not too painful.


    Hi Jane, yes of course we can keep in touch although as I said, I’m not currently fasting. My recovery is going to be measured in months rather than weeks or days but that is the nature of the injury. It is enormously frustrating to be so incapacitated but I can’t rush the rehab.

    I’m back home for the weekend so may try one fast day if I feel strong enough.

    How is the 5:2 going for you! Have you managed to keep the TDEE in check?

    BTW, how come this thread ended up in ‘recipes ‘ rather than General Health? Maybe we should start over in there where others may join in?

    Hi janeandmoses,

    I’m under active too, I have been since I was 19, they misdiagnosed it and wasn’t properly diagnosed until my early 30s. I’ve struggled to lose weight all my life.

    However, I have only been doing 5:2 for around 3 weeks now, I’ve lost some weight, but it’s very slow. I wonder how many more of us are underactive and struggle with weight loss.

    I’ve just been diagnosed with hypothyroidism and have found it very hard to lose weight which has crept on over time. I’ve been doing the 5:2 diet and find it really good, i’ve lost a bit of weight; 1kg in 3 weeks. This is actually quite good for me. However i’m starting to feel tired and like i did before I was diagnosed. Does the 5:2 diet alter how much thyroxin you need? I’m going to talk to my doctor when I go and get my first results, but wondered if anyone found the 5:2 made their symptoms worse?

    Hi Treegirl

    That’s really weird that you asked this question as I had been wondering the same thing myself. I’ve been exhausted recently and wondered if it was anything to do with 5:2. Not all doctors agree with 5:2 so I’m a bit reluctant to ask. Please let me know what yours says?


    Hi Treegirl and Dee, I think many feel tired on fast days and that’s quite normal. But there are loads of reasons we feel tired so it’s hard to put it down to either thyroid or diet. I don’t think losing weight should alter your thyroid needs, it hasn’t changed mine and I’ve lost around 12kg now.
    Good luck.

    Hi Panndie

    I think that depends on whether you have any thyroid tissue left to take over when your weight changes. My endo told me that if you lose weight, you may not need as much thyroxine, but I guess this depends on how much you lose and whether you still have thyroid tissue left. I don’t, I’ve been under active for almost 40 years, hashimoto’s.


    I know this thread is from last year, just upping it up in case there are more of us who have thyroid issues and are doing 5:2.

    I had a total thyroidectomy on 2012 and since then the weight slowly crept in. I also had a baby on 2014 and losing weight is so hard. My levothyroxine meds is at 100mcg and ,75 mcg on alternate days. My weight after pregnancy was at 62kg. With portion control it went down to 60kg after a year and down to 58,5 last june. I started 5:2 last july and am now in my 5th week. My weight today is at 55,3 kg.

    Aside from my fast days I am also trying to hit a tad under my TDEE which is at 1583 cals. My goal is to go down to 50-51 kg, as I am just 5’2″ tall. I use myfitnesspal app to keep track of my daily calorie intake. For calorie calculations I also use valued recipes app together with mfp.

    Hi Butterfly,

    If I’m reading correctly, you started 5:2 at 58.5 kg and have now reached 55.3 kg in 5 weeks. That’s about what is expected, around a pound a week loss. So that’s great, means that your thyroid medication is effective at helping you keep pace with the overall average loss of this forum as a whole.

    I’m also a thyroid patient. I’ve had Hashimotos Thyroiditis, which is my autoimmune system attacking my thyroid gland, so much of my thyroid gland isn’t functioning, if not all! So same or similar result as you, though different way I got there!

    I mention the thyroid medication as a factor, because when I’ve been on the wrong medication and/or dose, I have a much more difficult time losing weight, no matter how little I eat!

    I’ve been practicing 5:2 since late June 2016. I also use mfp, though do not count calories on NFDs. I also have shed about a pound a week, so I’m happy!

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