Weight Loss NHS

Under active thyroid

I'm not trying to make an excuse for myself not being able to lose weight, but I'm currently 12st and a half, this time last year I was 11 stone and a half. I've got an under active thyroid and was wondering if anyone knew why I'm putting weight on so easy and not being able to lose it.. I take my levothyroxine every day, I go for 30 minutes/ hour walk most days, I've just recently introduced lots of veg back into my diet.. Does anyone have any recommendations on how to lose weight?

6 Replies

Hi. I can't help I'm afraid but will be interested in the replies.

I've just been diagnosed with an underactive thyroid and took my first dose of levothyroxine (25mg) today.


Having an under active thyroid has definitely taken the tole of my life, I'm only 19 and was diagnosed with it when I was 17, it runs in my family. I've gained at least 2 stone, my hair falls out and leaves me with random patches on my head (only if I'm stressed).

I must say comfort eating has done this to me as well, I think I need to gain some will and won't power!


I am on 112.50 mg of thyroxine a day ((100 daily and half a 50 every second day). Thyroxine works and with the right dosage you don't have any issues. You will feel good and not tired or lethargic.

Food is the real issue. What you eat, what is in it and how much of it.


I have an underactive thyroid and have lost weight through the NHS 12 week weight loss program. It works for me. I went from Obese to just a tad above Overweight. It is not a diet but a way of learning how to change bad eating habits to healthy eating habit.

Check with your doctor regarding your dosage of thyroxine, you may need to increase it.

You have to eat well and there may be some food not suitable for you or for what you want to achieve. You are on the right track with vegetable.

Download the 12 weeks weight loss guide from NHS, you will find it will help you.


I've had an underactive thyroid for about 10 years (that i know of!). For the first year I gained 1-2kg per week! It took a few months to figure out my thyroxine dosage and then a few more months for my body to stabilise.

I put on weight extremely easily and i find that eating twice a day will keep my weight stable. If I eat 3 times I will absolutely gain weight. The only thing that has really helped me lose weight is low-carb. I couldn't keep it going unfortunately.

I haven't started this plan yet but I am going to start with increasing my activity as I am very concerned about my level of fitness. This is my priority and then I will start concentrating on diet. I am constantly aware of what I eat but do not control it enough to lose weight.

People tend to have general symptoms from thyroid but I have found that everyone's body also responds differently. I would say that if your hair is still falling out then your dosage isn't right yet. My hair fall starts within 5 days of dosage being wrong. That and my pulse rate are my key indicators of whether my dosage is right.

the best advice I can give is to get to know your body very well and experiment with diet and exercise until you figure out which combination works for you. You may never be your recommended weight but get as close as you can and as fit as you can.


It's a bit of a cycle - the underactive thyroid makes you feel cold & tired, so you don't feel up to exercising & comfort eat to combat it. Calorie count for a while to check your portion sizes, and try to eat stuff that comes in at under 5% fat. I had to do this for other medical reasons & it has worked, even when I can't exercise. When you're walking, try to increase the pace or carry something to increase your heart rate. Also do strength exercises - muscle burns fat and increasing your muscle will raise your metabolism.

It's also worth noting that it takes time to settle at the correct dosage, so if you're newly diagnosed, go back to your gp & ask to have the levels checked. I took 12 months to stabilize.


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