Hi all,
Haven't posted anything for a while but I've just started Intermittent Fasting (Fast 16hrs, eating period of 8hrs) and just wanted to know if anyone else have done this whilst having an under active thyroid (125mg per day).
Any help/ advise or support would be much appreciated. I am hoping to shed some weight by doing this so any feedback is welcome. Thanks
Are you now on adequate dose levothyroxine Previous posts your TSH was far too high at 11
125mcg is not a huge dose
When were thyroid and vitamin levels last tested?
Is TSH now under 2
Most people on levothyroxine, when adequately treated will have TSH well under one.
Most important results are always Ft3 followed by Ft4. Aiming for Ft3 at least 60% through range
guidelines on dose levothyroxine by weight
Even if we don’t start on full replacement dose, most people need to increase levothyroxine dose slowly upwards in 25mcg steps (retesting 6-8 weeks after each increase) until eventually on, or near full replacement dose
NICE guidelines on full replacement dose
nice.org.uk/guidance/ng145/...
1.3.6
Consider starting levothyroxine at a dosage of 1.6 micrograms per kilogram of body weight per day (rounded to the nearest 25 micrograms) for adults under 65 with primary hypothyroidism and no history of cardiovascular disease.
Also here
cks.nice.org.uk/topics/hypo...
gp-update.co.uk/Latest-Upda...
Traditionally we have tended to start patients on a low dose of levothyroxine and titrate it up over a period of months. RCT evidence suggests that for the majority of patients this is not necessary and may waste resources.
For patients aged >60y or with ischaemic heart disease, start levothyroxine at 25–50μg daily and titrate up every 3 to 6 weeks as tolerated.
For ALL other patients start at full replacement dose. For most this will equate to 1.6 μg/kg/day (approximately 100μg for a 60kg woman and 125μg for a 75kg man).
If you are starting treatment for subclinical hypothyroidism, this article advises starting at a dose close to the full treatment dose on the basis that it is difficult to assess symptom response unless a therapeutic dose has been trialled.
BMJ also clear on dose required
Yes - I've been on it for nearly 3 years, so well-ingrained now 
I just have water in the mornings - first cuppa at midday is utterly delicious - and try not to eat after 7pm.
I found it pretty easy to get used to - stopped being hungry in the mornings after a week or so and keep busy in the mornings so I don't have time to notice I haven't eaten anything.
BUT I find I can only lose weight if free T4 and free T3 are nice and high in range and key nutrients good ... I find the IF keeps my weight nice and stable but other people have found they lose quite a lot of weight on it. Having said that, I have lost nearly a stone in lock-down probably largely because I now also have a 4 -5 mile walk every day.
Good luck x
Interesting response. Do you find you feel anxious whilst doing IF though as that’s what happened to me personally
I lost weight but felt anxious so had to stop unfortunately
No, not at all - but we're all different For me it's just a way of life now x
Of course we are thank you x
I’ve thought about this but am a bit woozy with hunger when I get up in the morning and couldn’t wait until mid-day to eat. In the past I’ve used the 5:2 and lost weight, but only when optimally medicated.
You can pick which hours to eat in - so might it work if you have breakfast and a main meal mid-pm? But absolutely agree you must be optimally medicated to stand a chance!
I did the 5:2 for a bit (at my fattest) and lost a stone quickly then not another ounce. Unlike Cat013 my weight is stable on IF. I'm not currently trying to lose weight - those cheeky mid-afternoon crumpets wouldn't be helping if I were - but have lost weight in the last two summers - when it's hot I can eat less and lose - and haven't regained any weight lost since starting IF. So I guess it works for me, but clearly not for everyone x
Yes I do this. Well try 😂. I did previously lose weight on it but like all other eating plans it stops dead in its tracks after a while and the weight creeps back on. Having tried to lose weight for many many years, like others have mentioned, for many of us it’s down to thyroid levels. I doubt I’ll ever lose weight until my t3 is nice and high (but in range of course) and it’s currently just hit the 5 range. So I guess we’ll see soon enough! In the meantime I have to keep my calories down.
If it works for you fantastic 😃. It certainly did for me initially. If it doesn’t I’d consider working on increasing your t3/t4 levels and getting your TSH down if needs be. Best of luck x
Have a look at SlowDragon’s reply.
If you struggle to lose weight you may find you’re not optimally medicated yet. Or it could be partly to do with vitamin levels even. Or a food intolerance/leaky gut.
some of us need to have our t3 higher in range than others. Getting it higher in range is to do with being optimally medicated. We’re all different.
Based on my t3 being 5.01 (range goes up to 6.8) and not shifting a pound unless I starve (which of course is no good either) I’m assuming I’m one of those people. But I don’t know your current results to be able to make any helpful comments. Have you had a recent thyroid blood test?
Hi, there. I'm also on IF for the last week, after struggling for 2 years now to lose 15kg that I put on, most probably because of my thyroid. My weight stabilised after I started eutyrox. I'm now on 100mg.
Although I'm feeling quite ok, not loosing weight it's driving me crazy. Although I walk for 5,5 km every single day, and for the last 2 months I was following a prescribed diet from a specialist (doctor) I didn't mange to loose weight. So, I decided to give IF a try. I started with 16:8 and now I'm trying to be somewhere around 20:4. To be honest after a week on IF I didn't loose any weight, but I decided to give it more time. According to my latest blood result, I think I'm doing ok regarding my levels. My FT3 is above the upper limit.
TSH: 0.03 (0.27-4.20), FT4: 17.54 (12-22), FT3: 7.48 (3.95-6.80)
Good luck!
I’ve done 5:2 for years (on & off) it’s been the only way I’ve kept to what I feel like is my ideal weight. There seem to be so many other good health reasons to do it too. I’ve had a couple of months off it recently (just got out of the habit) and I’ve put on about 4kg. This may be another indicator that I’m slightly under medicated?🤔
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