Reasons for weight gain with Hypothyroidism?

Hello folks,

I've been trying to find out exactly why Hypothyroidism causes weight gain but can't seem to find anything on it. Does anybody here know the reasons?

My Dr said that my body can't metabolise the energy from food, and I wonder:

1) If this is true?

2) If this is why I'm so hungry all the time - my body doesn't think it's getting enough food for energy so it makes me want to eat more?

3) If the body can't use metabolise the energy from food, does the body then store the energy from food as fat, if it can't use it?

Does anyone know the answers to any of these questions?

Thanks for reading :)

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24 Replies

  • i think its because it slow down the whole system

    like when i was hyper i lost aloooot of weight even when i was eating more than 3000 cals everyday!

    so in hypo is the opposite.the whole body needs thyroxine to keep things going good.when we are hypo our thyroid produces les and less thyroxine.that is responsible for our slow down everything.

    i strongly believe that weight loss when hypothyroidism exist is possible through healthy food and exersise!:)

  • It's because we tend to have a low basal metabolic rate (BMR). As Joannagof says, it slows everything down. The American Thyroid Association says

    "Since the BMR in the patient with hypothyroidism (see Hypothyroidism brochure) is decreased, an underactive thyroid is generally associated with some weight gain. The weight gain is often greater in those individuals with more severe hypothyroidism. However, the decrease in BMR due to hypothyroidism is usually much less dramatic than the marked increase seen in hyperthyroidism, leading to more modest alterations in weight due to the underactive thyroid. The cause of the weight gain in hypothyroid individuals is also complex, and not always related to excess fat accumulation. Most of the extra weight gained in hypothyroid individuals is due to excess accumulation of salt and water. Massive weight gain is rarely associated with hypothyroidism. In general, 5-10 pounds of body weight may be attributable to the thyroid, depending on the severity of the hypothyroidism. Finally, if weight gain is the only symptom of hypothyroidism that is present, it is less likely that the weight gain is solely due to the thyroid."

    I personally don't agree with 5 to 10 pounds. It took about 2 years for me to be even tested for hypothyroidism and I had probably put on about 2 stone, maybe more.

  • I too was sceptical of the 5 to 10 pounds. When I went looking the only figures that are out there are 5 to 10 pounds or 5 to 10 %, due to water and salt being retained.

    Strikes me, it's one of those things that is just being repeated and they're all quoting one another.

  • hypothyroid means your entire metabolism is slowed to a crawl and your body cannot convert food into energy but instead stores it as fat

  • Thanks for the reply,

    I'm interested to find out more about the body storing the energy from food as fat as it can't use it. Do you know where I can find out about this. Do you happen know where you found out about it from?

  • any google search on hypothyroid+metabolism should be helpful

  • And then there's the explanation... Well. For all sorts!

  • I've often wondered why Ord has been so unfairly forgotten. Everyone on here and on other thyroid sites refers to Hashi's as the sole cause of autoimmune disease leading to hypothyroidism.

    But, officially, I think Hashi's is the form of autoimmune disease which causes hypothyroidism with a goitre.

    Ord's is the form of autoimmune disease which causes hypothyroidism without a goitre.

    But poor old Dr Ord is hardly remembered or mentioned amongst patients now, and autoimmune thyroid disease is all blamed on Hashi's.

    P.S. Jazzw I love that link you've posted.

  • I thought with Ord's, the main feature is atrophy.

  • Well, yes, true. So there would be no goitre.

  • Some additional information - sadly the first two full items are behind a paywall.

    Type 1: Euthyroid Autoimmune Thyroiditis (Hashimoto’s thyroiditis)



    Type 2: Hypothyroid Autoimmune Thyroiditis (Hashimoto’s thyroiditis)



    Type 3: Autoimmune Thyroiditis (Graves’ disease)



    The disease should really be called Ord-Hashimoto’s thyroiditis. I rest my case ... but I prefer “Autoimmune Thyroiditis Type 2.”

    Hashimoto’s original description included two salient morphologic features, goiter and widespread lymphoid infiltration. Ord quite clearly described a shrunken fibrotic gland, and these glands show a few foci of surviving thyroid follicles with lymphoid infiltrate. To the pathologist these are clearly distinct conditions.


    Delivered before the Royal College of Physicians,

    By WILLIAM M. ORD, M.D., F.R.C.P.

  • Thanks for the reply Jazzw,

    I had a look at images of Myxedema but I don't think that relates to me, I don't have puffy eyes or any swellings.

  • Hi

    Please explore Zoe Harcombe:;

    I was gaining and gaining and gaining weight and very uncomfortable, bloating and food un-digesting.

    I ate healthily (the so called governments recommended 5 a day plate with plenty of good quality protein) and running too with very fatigued muscles. However I didn't lose one pound!

    I went from 11st 8 lbs in October, (lost 5 pounds in a week) and got weighed Tuesday, weigh in at 10st 1lb!

    What Zoe teaches us in terms of how our bodies metabolize fats and carbs differently is priceless!!

  • I had a look at the website but couldn't find anything about Hypothyroidism, does she address this specifically?

  • Basically because thyroid hormones (mostly T3) are what run your whole body. If you don't have enough, your body slows down to conserve energy and so eating very little makes you gain weight (similar to the changes that happen when you diet or starve). Only getting free T3 to an optimum level will rev up your metabolism again. Also, many hypo people create too much mucin, which is stored under the skin and looks like fat or water retention, but isn't. If your medication level is correct, you should lose weight and mucin. You may be hungry because you are deficient in vitamins, minerals and other nutrients, either because you aren't eating enough or because you have low stomach acid (very common with hypo) so can't break down the food properly. Some people don't get hungry. If you have Hashi's (autoimmune thyroiditis) you can swing between high and low hormone levels, which could also affect your appetite.

  • It is not the illness but the mediction that makes you put on weight.

  • Glynisrose, do you know what the mechanism is that explains *why* Levothyroxine causes weight gain?

  • I'm not sure that's true, but if it were true it might be because a) Levo is T4 only b) Too little levo is given so T3 still low c) To get enough T3, you need "too much" T4 which then converts to RT3, so T3 is still too low d) Many people can't convert T4 to T3 well, so don't get enough T3.

  • I found that I actually lost weight when I first went on T4, but it has crept back on. I am now on T4 T3 combo but no more weight is shifting. I know I am eating too much, I just find I get so hungry and am wondering if the hypothyroidism could be causing this, because there is some problem with using the energy from food.

  • Glynisrose - I beg to differ as I am not on any medication yet and am overweight with eating very little food

  • W

    Zoe doesn't specifically address hypothyroidism, however I am losing weight following her advice.

    I am finding that I can't tolerate or metabolize carbs.

    I have found Fats and proteins digest really quickly.

  • An interesting article about weight gain due to a low T3 written by Dr Westin Childs:

    As a solution it also discusses reducing inflammation, reverse T3 and stopping any calorie restricted diets.

  • Personally eating on regular basis has helped me and I have lost 12 kilos!

  • You will probably find the less you eat the more you gain! I believe in the fact that there is such a thing as eating too little as well as eating too much. If you don't get the calories your body needs then you are lost! I have to force myself to eat regular meals at regular times but I have lost weight.

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