Recently I completed a 10 week experiment doing a variation of a cyclic ketogenic diet called the Carb Nite Solution, which basically entails eating strict low carb (less than 30 gm per day) with one 6-8 hr window of massive carb loading per week. At the end of this experiment, before going on a trip to Italy, I had a series of fasting labs drawn.
So far we’ve looked at my:
I’d now like to explore my thyroid hormone levels (if you want to learn more about the basics of thyroid physiology I go into it briefly in one of my earlier posts).
One of the main purposes of adding the Carb Nite according to Kiefer is to prevent the body from slowing down it’s metabolism. This is important because as you can see from the above numbers, after doing 90 days of nutritional ketosis, I became hypothyroid (subclinically hypothyroid depending on who you ask). You can see that after adding carbs back into my diet, my thyroid numbers drastically improved! So it looks like having some carbs/insulin onboard is necessary for me to maintain my thyroid function.
After 10 weeks of Carb Nite, my thyroid hormone levels didn’t take too much of a hit. It looks like the 1-2 days of carb refeeds really did the trick in preventing me from becoming hypothyroid. The TSH did go up from 1.23 to 2.23 and my RT3 is still higher than I would like, but it these numbers definitely aren’t as bad as what I saw after 90 days of pure ketosis.
On Jimmy Moore’s Livin la vida low carb podcast, Chris Kreser came on as a guest host and discussed how going low carb can have detrimental effects on your thyoid (you can listen to it here). This podcast was serendipitously released yesterday!
Here’s are some highlights:
- Low carb diets can cause hypothyroidism
- One way to address this is simply to add carbs back into diet
- Insulin required to make conversion from T4 to T3
- People who do very low carb and people who fast, who have low insulin levels, show a decreased conversion of T4 to T3
- This can cause no issues in people… OR these can cause worsened hypothyroid symptoms in people.
- Can supplement with selenium (fish and brazil nuts) and zinc (red meats, organ meats, shellfish) which will help improve conversion of T4 to T3.
- Must make sure iodine levels are sufficient
- Reduce inflammation and stress (which also decease conversion of T4 to T3, decrease TSH output, AND decrease sensitivity to thyroid hormone)
Having the 1-2 weekly Carb Nites really did provide enough stimulation to my thyroid to prevent hypothyroidism. I’ve read in some places that an optimal TSH is 1.00 or less…. and my RT3 is definitely still too high, but as you can see, this is still much better compared what I found after being in uninterrupted ketosis.
I suspect that the hypothyroidism from being in ketosis too long contributed to my limited weight loss.
After 12 weeks of nutritional ketosis, my umbilical circumference only changed from 34.5 to 33.5 inches and my weight only decreased from 180 to 178 lbs. Not a very significant change at all… hard to believe that hypothyroidism didn’t play a significant role in these paltry results.
When I woke up this morning, it suddenly occurred to me that my supplement stack was different during this time around compared to when I did straight ketosis. One of the components that I added in was Mark Sisson’s Damage Control Master Formula which has Selenium, Zinc, and Potassium Iodide in it, among a host of other things…
So with this confounder, I can’t say for certain that the carb refeeds were 100% responsible for my thyroid levels…
Image credit from yxhealth.com