Carb Back-Loading and Thyroid Hormone

Carb Back-Loading and Thyroid Hormone

After I reached the 8 week mark of my Carb Back-Loading experiment, I planned to draw a series of blood tests to see where things stood compared to my most recent set of labs which were drawn after doing Carb Nite for 10 weeks.

Here is a brief summary I wrote in the early life of this blog regarding thyroid physiology:

• Thyroid Stimulating Hormone (TSH) – This is the hormone your brain sends out telling your thyroid gland to produce more thyroid hormone.  If there is too little thyroid hormone, your brain will send out more TSH, and if there is too much thyroid hormone, it will release less TSH.
  
• Free T4 – This is the form of thyroid hormone sent out by the thyroid gland to regulate metabolism in the rest of the body.
• Free T3 – A more potent form of thyroid hormone.  Tissues that receive T4 will convert it to T3 which is about 4x more potent than T4.  The reason T4 is sent out instead of T3 by the thyroid gland is because T3 only has a half life of 2.5 days where has T4 has a half life of 6.5 days.
• Reverse T3 (rT3) – Tissues that receive T4 can also convert it to rT3, an inactive form of T3.  This occurs in certain conditions in which your body tries to conserve energy by slowing down metabolism such as fasting, low carbohydrate intake, physical or emotional stress, illnesses, surgery etc.  Thus, under these conditions, not only will you have less overall T3 floating around, but rT3 can block T3 receptors so that the T3 you have left are even less effective.

Here are my latest results:

As a quick summary, going back to 8/30/2011 and 11/16/2012 while doing the Slow Carb Diet, my TSH was in a pretty good range between 1.00 and 2.00.  Unfortunately at the time I didn’t draw Free T4, Free T3, or rT3 levels.

On 3/11/13 after 90 days of nutritional ketosis you can see that my TSH took a dramatic bump to 4.35.  It was at this point that I first drew all the other thyroid labs.  Thus for the Free T4, Free T3, and rT3, this was my baseline.  Nutritional ketosis had pushed me into hypothyroid territory (which also happened to Ben Greenfield).  Turns out being in ketosis for too long of a time, coupled with a lot of activity can send signals to your brain that you are in a starvation mode which causes a down shift in metabolism.  I don’t think this happens to everyone who goes into ketosis, but it happens to enough people that it’s something that folks should be aware of.

At this point I was also dealing with a sky high LDL-P and the keto-rash (prurigo pigmentosa), so my thought was that I could kill all three birds with one stone by adding carbs back into my diet and ending my nutritional ketosis experiment.

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On 5/9/2013, after almost two months of eating more carbs my TSH came back down and my Free T3 and Free T4 improved, so this seemingly did the trick!  The only issue was that my rT3 level was still too high.

I stopped experimenting for a while because the BJJ Cavewife and I were preoccupied with planning our wedding, but once that was through, I discovered Carb Nite which is a cyclic ketogenic diet (carbs once a week).  My thinking was that this method would confer the benefits of a ketogenic diet (weight loss, metabolic efficiency, decreased reactive oxygenated species, decreased glycation end products, etc.) without the detriments (keto rash, high cholesterol, hypothyroidism).

After 10 weeks of being on Carb Nite, on 12/16/13 I re-checked my thyroid levels and found that things only worsened slightly.  My TSH took a bump, but not nearly as high as it did while being in strict ketosis.  My rT3 got worse however, although I’m not sure how much this had to do with the fact that my work schedule had changed from a second shift schedule into a graveyard/overnight schedule.

Now, I’m in the midst of experimenting with Carb Back-Loading, Kiefer’s targeted ketogenic diet (carbs only after you work out), and after 8 weeks I drew my latest set of labs.  As you can see my TSH improved and is now closer to 1.00 than it’s ever been.  My rT3 came down to it’s lowest point, although it’s still higher than I would like… (I suspect this has to do more with my graveyard shift than anything else).

It looks like the amount of carbs I’m taking in while following Carb Back-Loading (since I work out around 3 times a week, I take in carbs 3 times a week) is providing enough of a signal to my body to continue to pump out thyroid hormone!  This is a much more tolerable method of optimizing my thyroid as opposed to what Ben Greenfield did, which was eating a lot of liver, dessicated thyroid, and sweetbreads.  Bleagh…. (now before you go all Green Eggs and Ham on me… I’ve tried the liver and the sweetbread and it almost made me vomit).

So at least with regard to my thyroid the optimal diets are ranked in this order:

Carb Back-Loading > Slow Carb Diet > Carb Nite > Strict Nutritional Ketosis