Question From Reader Uma Regarding Ketosis and Thyroid

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As I was in the process of typing a response, it occurred to me make this a separate post because my answer was getting longer than I expected, and I figured that other folks may have similar questions.


This question is probably not related to article. But I wanted to get your attention and hence this question on your latest post. Thanks for all the awesome detailed info. It really helps people. I read the effect ketosis had on your thyroid. I havent started on this diet but doing my research before getting into it. My family has had thyroid problem and I feel I am sensitive to the issues as well. so far my tests are okay. A lot of reserarch articles out there say ketosis affects thyroid leading to hypothy. I also like to be active. lift heavy weights , cardio, pilates etc.

Considering all this, I am thinking of taking up IF. What do you suggest or think? Have you tried IF? Any thoughts will be helpful. Also read that IF does not impact thyroid in the way ketosis does. I also do not want to deprive myself of fruits, vegies and gluten free carbs.

Considering that I am married and my hubby isnt into all of this… ketosis really does not seem to be a long term thing for me. Off late I put on too much weight due to a lot of stress and study work that I had to do with no time for careful easting and exercise. Sorry for the long post. Please let me know your thoughts. Thanks a lot!


Ketosis And Its Variants

Thanks for stopping by.  Let me know if I’m off base at all here, but it seems your ultimate goal is weight loss, is this correct?

True it has been reported that ketosis can affect the thyroid, as you’ve seen with my lab tests, but I don’t think this is the case for everyone, since there are a lot of people who do nutritional ketosis without any problems, Jimmy Moore being one example.

If you really wanted to try ketosis, I would recommend that you experiment with it for a month.  Go all out nutritional ketosis, and then at the end of 4 weeks assess how you feel.  At this time you will be able to answer these questions:

1. Did I lose weight, or rather body fat?
2. Are things moving in the right direction?
3. How do I feel overall?
4. How did I feel before and after my workouts
5. Was I able to perform to the level that I want?
6. Do I have any signs or symptoms of hypothyroidism?

You can also get a blood test to see where your thyroid numbers are after these 4 weeks, with a standard thyroid panel for $49.00 from RequestATest, although this does not include an RT3 level.

After answering these questions, it should give you a better idea of how you choose to proceed from there.

  • Maybe you just hate it and it’s not working for you… well then at least you’ve tried it out and found out for yourself.
    • I myself did nutritional ketosis for 60 days and then continued it to 90 days, and found that my prurigo pigmentosa rash got really bad!  Also I too missed carbs and the amount of weight I lost and the body composition change I experienced wasn’t very dramatic.  My thyroid and cholesterol numbers took major hits AND I was running out of gas when doing BJJ.  Now that I know all this, I can say that in my situation, strict ketosis isn’t optimal for me, but I’m glad I experimented with it.
  • Maybe it’s working great but you just really miss eating carbs… well then maybe you can explore a cyclic ketogenic approach, staying keto Mon to Fri and then going balls to wall carb-crazy over the weekend.
    • I tried something similar when I experimented with the Carb Nite Solution, and found that while my results were great, my labs still took a bit of a hit, my rash would appear occasionally (though not as bad as when doing strict ketosis), and I didn’t have as much energy when doing BJJ as I wanted.  So this method worked a better for me… but still wasn’t optimal.
  • Maybe it’s working great but you aren’t performing as well as you want to with your weight lifting, pilates, etc…  then maybe the targeted ketogenic diet is the correct approach where you eat carbs only after days you train.
    • This is what I’m currently experimenting with Carb Back-Loading… results to remain to be seen.

Intermittent Fasting

This is probably the best write up I’ve come across regarding intermittent fasting.  Dr. Berardi experimented with each variation of intermittent fasting and documented his results in a very systematic way.  It is a great read and I highly recommend spending the 1-2 hours going through it.  He explores:

  • 36 hr fast : 12 hr feed
  • 24 hr fast 1-2 times per week
  • 16 hr fast : 8 hr feed
  • 20 hr fast : 4 hr feed

Here are some other great posts on IF from Mark’s Daily Apple, one of my favorite blogs:


Now that I’ve linked to all this, I can say that I haven’t come across anything that discusses the effect of IF on thyroid function.

For me, personally, I try to do fast for 12-14 hrs per day.  I’ve pretty much been starting my days in the same way, with a bulletproof coffee (coffee with butter and MCT oil) as a way to jump start my brain.  Most folks agree that this doesn’t count as breaking the fast since the fats and oils don’t stimulate insulin release and initiate other metabolic changes that interrupt the benefits of fasting (autophagy and what not).

This can be done with any of the keto diet variations and in my experience does not interfere with ketosis.

I hope this long winded response was helpful!

5 Responses to Question From Reader Uma Regarding Ketosis and Thyroid

  1. sootedninjas says: another site that has a lot of details on IF but no thryoid info

  2. Mary Jo Kringas says:

    About low carb and hypothyroid. This is my experience. I have low carbed for about 11 years and lost 130 pounds of weight. Before eating low carb, I would exercise to exhaustion and not lose any weight. When I started low carb eating (20 g net carbs a day, no fruit), I gave up exercise (I now see that my thyroid was too compromised to support exercise anyway), and I meditated. Yes, that is right.. I lost 130 lb. without any exercise at all.. just by not raising my insulin levels with the foods I ate. Recently, I have seen a thyroid specialist and have been diagnosed as hypothyroid. I have been taking T3 for about 5 months and I finally feel energetic enough to exercise.
    My experience is that eating low carb and being in ketosis, did not create more of a hypothyroid problem than I already had. Considering that you like to be active, if you notice that you do not feel like being active, I would consider this to be a strong indicator to get my thyroid tested, and yes, it was very important for me to test REVERSE t3.
    I have not tried intermittent fasting… I love to eat and I refuse to engage in the “punishment based mentality” of starving.

  3. mike says:

    Chris Kresser and possibly others have said that a low carb diet can lower the conversion of thyroid between t3 or t4. However, Jeff Volek, claims he has seen no thyroid issues in any of his test subjects from eating low carb. Volek does admit to not doing full thyroid panels. There could also be an thyroid issue from any reduction in calories long term. Dieting in general, cutting calories too far, could slow metabolism and or thyroid over time as well.

    Clearly, more testing is needed in this area. You also can consider a cyclical ketogenic diet where you ingest a lot of carbs one a week or every ten days. This is “supposed” to mitigate any issue with hormonal down regulation.

  4. uma says:

    THANK YOU! First of all thanks for taking the time out and answering in such a detailed manner. appreciate the help and effort. You made my day. You are absolutely right and I will give it a shot for a while and I will know. I don’t think a month will have any adverse affects. I am reading the links you and other readers have posted.
    Great blog . Great info. Take care! (have i said thank you? 😉

  5. Mike says:

    Uma, if your going to try a keto diet or a cyclical kept diet, I would strongly suggest buying two scales from different brands that do estimates of body fat and water. Tracking weight only, can really be misleading.

    For example, sometimes I don’t see weekly weight loss, but the scales read a fat loss of 1 to 2 pounds. I don’t know how this is physically possible, but it happens. I have also seen people asking “how can I have lost inches, but not weight”. This must be a similar issue.

    I think if you do keto 6.5 days and once a week have a big meal including carbs and a big dessert, you will be very happy. Keto allows you to maintain a very stable lower level of hunger and mood. Having a nice spike of carbs weekly will help you hormonally and mentally.

    You can also experiment with black coffee, tiny bit of heavy cream and skipping breakfast. If you like breakfast, than that’s ok too, mix it up every other day.

    Just finished my bacon and egg lunch, took my fish oil and I am looking forward to pastries, cookies, dinner and carbs tonight.

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