Don't be fooled by the bread demons, you CAN be healthy on a low-carb diet
If you’ve been turned on to the low-carb Paleo diet craze, you may have noticed increased energy, better digestion and happier mood, and a shrinking waist line. Good for you. But some folks who’ve taken the Primal leap—particularly those who were previously on a high-carb diet—have been faced with unexpected side effects waving them back to the world of bread, sugary fruits and sweet potato casserole.
Interestingly, these side effects include a wide range of symptoms that are nearly identical to symptoms of severe thyroid hormone deficiency. More interestingly, lab tests often show normal or near normal thyroid function. More interesting still is that these symptoms seem to only be relieved by adding back carbs into the diet, sometimes upward of 300 grams—a level I consider to be very likely to harm.
Why is this happening? Is it that low-carb simply doesn’t work for everyone, or is something else going on?
In an effort to get to the bottom of this, low-carb asking his cadre of low-carb literate practitioners to weigh in on the issue with our opinions. This so happens to be an issue I’ve been pondering since reading about the controversy over safe starches, and a couple pieces of the puzzle recently fell into place that I think I add up to at least one explanation for the debilitating symptoms some people develop on going low-carb, and offer a method for anyone going low-carb to do so without problems.
Here’s what I discovered about those with thyroid problems.
Abrupt Change May Be too Much For the Thyroid
People who run into trouble going low-carb seem to follow a pattern. They follow any number of diets from SAD to vegan before making a relatively abrupt switch to a low carb (often less than 50 gm) diet. At first they lose weight as hoped but then, instead of feeling more energetic from their weight loss, they develop fatigue, sometimes accompanied by symptoms of low thyroid function including cold extremities, hair loss, and digestive problems. Only by consuming more carbs again can they reduce these symptoms.
Because their fatigue and other symptoms are classic for thyroid malfunction, many will get their levels tested, only to come away confused when the tests health practitioners typically order (TSH and T4) come out normal.
Those who get more extensive testing may get a test called reverse T3, or rT3 for short. These are often abnormally high, leaving them to believe they have found the root of the problem. Some are given a prescription for T3 in hopes of regaining energy and the intervention seems to help, at least a little.
Reverse T3 is a kind of chemical opposite of regular T3, a mirror image compound called an enantiomer. Reverse T3 has opposite effects of T3, and has long been associated with a set of symptoms aptly called hibernation syndrome—fatigue, weight gain, and so on. If you have suffered from severe hypothyroidism, you may have gone through times where you felt like you really just want to crawl away to a quiet place and rest for a long, long while. Your body was telling you to hibernate.
 
In addition to making our energy go dormant, high rT3 is also associated with increased levels of LDL, often in the 200s.
Interestingly, those who have added carbs back into their diet and have gotten retested find that their levels of rT3 have gone down without additional T3 supplementation. What’s more, if their LDL was high, adding carbs back to the diet also solved that problem as well, completely counter to the idea that carbs drive insulin which increases LDL.
I have to admit that though I have cared for thousands of people following low carb diets to my knowledge none ran into this problem so I paid very little attention to the issue with rT3. Only when I started reading about people suffering from thyroid side effects from following low carb did I started seriously thinking about that pesky little molecule. I wondered what it was supposed to be good for: Why would nature program our biology to manufacture a compound that seems to do little other than make people miserable and potentially clog our arteries?