Why do people gain weight on levo?: Is it because... - Thyroid UK

Thyroid UK

111,229 members129,292 posts

Why do people gain weight on levo?


Is it because of the actual medication, is it that people are under medicated / condition is worsening whilst starting meds so it's inadequate, due to being unwell people overeat?

I'm only two weeks in to starting levo at low dose of 25mg. My sugar cravings are mad, I'm way overeating and can feel myself gaining weight. Is this just a separate issue I need to get a grip of or is the hypo a reason for me eating so much? Or is this something unanswerable!

The overeating started before the meds, probably over the last year.

10 Replies

Hi, misslissa, think of your thyroid as your body's thermostat. When it is underactive, all your body functions sloooowwwww waaaayyy down, ...... heart rate, body temp, digestion, blood pressure etc. Often body temp runs 1 - 3 degrees below normal. You wouldn't think just that would have such a profound effect on keeping one's weight down but it can and does for many folks. Plus when one feels lousy and is lethargic, that listlessness and lack of energy can help keep the weight on.

Conversely, when one has an overactive thyroid, everything is revved up including body temp which makes it difficult for the sufferer to maintain or gain weight.

An underactive thyroid and just getting older can mean that we don't make as much stomach acid as is necessary to properly digest our food. That stomach acid also helps to keep bacteria and fungus killed and at bay. Your sugar cravings might be indicating that you have an overgrowth of candida. Candida loves sugar.


Adequate amounts of stomach acid are also required for optimal absorption of various minerals and vitamins so getting your B 12, D 3 and iron levels checked would be prudent. So, it may be difficult to lose weight while getting your thyroid meds under control and optimized, but do try to eat sensibly and eat plenty of protein with your meals... even with snacks and avoid the fat-free and sugar-free stuff that is usually loaded with chemicals. The protein and adding good quality fats (olive oil/coconut) will help you avoid sugar spikes and to feel satisfied.

ps.... some folks try going gluten free. It seems to help with bloating/digestion etc. I think there is a couple of good books available called 'Wheat Belly' and 'Grain Brain'? I haven't read them myself. Maybe someone else can advise?

Thanks, I need to up my protein a lot. I used to eat higher protein diet so I know the right things to do - I'm just incapable of doing them these days.

Interesting about the candida, for years I suffered with recurrent thrush (sorry tmi) and knew sugar caused flare ups. Maybe I need to really try and cut sugar, it's very scary as I eat it a lot now. So unhealthy.

I'm dubious of gluten free, I think before going that extreme I need to optimise my general diet and see where I am then. If no improvement perhaps gluten is an issue.

That recurrent thrush is a clue that you may not be handling candida very well. We all have a certain amount of candida in our system but it is usually kept at low numbers and under control by our immune system and stomach acid and probiotics.

It sounds like you are diet 'literate' and know what to do but maybe a book like 'Entering the Zone' by Dr. Barry Sears (not really a diet book as much as a 'I am sick and tired of feeling sick and tired' book) or the 'Sugar Busters' book might be helpful and/or motivating.

I use stevia a little bit but mainly I use natural cane sugar like Sucanat ... a product that is just organic, ground-up, dried cane juice for my sugar needs. I think it is healthier than processed sugar products but... if you are fighting candida, no sugar or very little is best.

When I was diagnosed with breast cancer, I had to cut out sugar (cancer also loves sugar/glucose) and learned to drink my coffee black etc. and to avoid high glycemic foods that turn to 'sugar' in our system. I went slowly so I didn't stress myself out. One thing at a time. I agree about going gluten free, maybe for later?

Are you eating any sugar substitutes ?

misslissa in reply to Conmaster

You mean artificial? No, don't agree with any of that or low fat etc

I have a theory that as levo is T4 alone (the storage hormone) it encourages the body to store everything, including food. Your body can turn anything into fat to store. The trick seems to be to get off levo asap and take NDT.

misslissa in reply to Glynisrose

I'm researching and if levo no good I'll swap


Good question! When I was diagnosed with Hashimoto's, 16 years ago, I was told all I would need was to take a pill of T4 every day for the rest of my life, and everything would be fine. My doctor at the time said: "Give it a couple of weeks on levothyroxine, and it will be like you were never ill in the first place".

Well, it turned out not to be as easy as that...far from it.

I speculate that the hormone T3 is far more important than it is usually given credit for. The idea is that the storage hormone, T4, is converted to T3 in the body as needed, mainly in the liver, but also on cellular level if I'm not mistaken. It's often said by conventional doctors that is the reason you don't need extra T3; just give the body T4, and it will convert whatever it needs to T3.

It does not seem to work that way for many. I know for a fact it does not work that way for me.

T4 is just that: a storage hormone, meant to be used for a specific purpose - conversion to T3. It even seems T4 on its own is metabolically inactive. If the body cannot convert it, for whatever reason (iron deficiency, adrenal fatigue...), you remain hypothyroid, no matter how much T4 you have circulating in your body.

Another theory of mine is that, after being hypothyroid for years (as is often the case when you have Hashimoto's, or autoimmune hypothyroidism, as the thyroid is not destroyed overnight, but over a long period of time, sometimes years before diagnosed), the whole balance in your body - hormonal, cellular, organic - changes, and that won't change back just because you start taking a pill a day.

Many hypothyroid patients struggle with adrenal fatigue, too often ignored by conventional doctors who dismiss it as a myth. Most conventional doctors won't even know how to diagnose adrenal fatigue.

I have a colleague who had her thyroid gland removed because of a tumour five years ago. She was put on thyroxine the same day, is taking 125 mcg daily since, and has never had a problem. She feels fine, has never put on weight, and there is no indication she is hormone deficient in any way. I, on the other hand, was on 200 mcg of T4 for years before switching to NDT, and I was still struggling even on what most doctors consider a huge dose of T4.

This has caused me to believe that people who are not hormone deficient for years, but is put on treatment from one day to the next (like my colleague), never have their whole hormone system and balance disrupted in the way that people with slow-progressing Hashimoto's thyroiditis often do.

Thanks everyone.

My adrenal test has thrown up some highs and lows which need addressing.

It's weird, for years I've struggled, was diagnosed with CFS 6 years ago and managed it fairly well getting myself much better. I've had a lot of full on stress which I honestly think caused the CFS, Dr's thought I was mad I think but I kept saying stress is making me ill.

Everything changed when I got pregnant in 2012, at about 18 weeks I started feeling great, are well, had energy, after birth I lost lots of weight without trying (put down to breastfeeding), felt happy and energetic. Best I've looked and felt in years.

Then from about last May I started going downhill. I started working, stopped being full time mummy, up in the night with son every night (still am), still breastfeeding, physical job etc and I started gaining weight, being totally vacant, loads of joint pain, hair still falling out but put down to being a mum. I'm not sure what changed, I so desperately want to go back to where I was in that great period.

Levo works well for many but they don't post on here if they are fine so we never really hear the successes!

You may also like...