Going Low-Carb too Fast May Trigger Thyroid Troubles and Hormone Imbalance

If you’ve been turned on to the low-carb Paleo diet craze, you may have noticed increased energy, better digestion, happier mood, and a shrinking waistline. 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?

This article is continued below...(scroll down)

---

It helped. I feel great.

"It’s helped. I feel great."

Kobe Bryant

NBA baskeball player

This has been life changing

"Let me tell you this has been life-changing. I have all of her books, in audible and ebooks! I have gotten rid of all the hateful 8 oils. I have trained my body to eat its own previously toxic body fat. Download that pod it's a game changer!"

Megyn Kelly

Broadcaster / The Megyn Kelly Show

Life changing

Deep Nutrition changed my life.

Jesse Watters

Fox News Primetime host

Saved my life

I would like to thank you for literally saving my life. Back in February, I had to be hospitalized while on vacation in Phoenix with an A1C of 11% and had to start taking 2 types of insulin and 2 other meds. I read the Fatburn Fix in April, and followed the program to a tee, and I’m down by 15 pounds, 6.8 A1C, and only one once weekly diabetes medicine. Prior to reading the book, it was almost impossible for me to lose weight as a diabetic. 

Leontyne Tompkins

I feel free

For the last month, I have really been reading all labels on everything. I have completely remove those 8 oils you talk about. I must tell you, I feel great! I have more energy and I am now 197 lbs (have always been around 205 to 210lbs). I eat potatoes with real butter, grass fed steak, pasta with the right toppings. I eat everything! I seem to crave less sugar. I love it! 

Robert Kirkendall

I feel so much better

I had terrible aches and pains everywhere in my body, my hands, shoulders and knees. I feel so much better and the way I feel is motivating me every day! Thank you

Mike Deb Wootan Burcin

Better than ever

I am an anesthesiologist in Orlando and a huge fan of both of your books! I have been incorporating your principles for the last 10 months and feel that my health is better than ever.

Marnie Robinson, MD

My allergies disappeared

The biggest difference for me (and a surprising one) is that my allergies have almost completely disappeared! This is a big deal for me, because I’ve had allergies most of my life and they have often affected what I do which is a teaching music in [a public school district].  In general, I feel much better and have more consistent energy throughout the day.

Erica Turrell

Heart Palpitations have Stopped

I’ve lost 20+ pounds (also fasting 16-24 hours daily) and haven’t had palpitations except for one occasion — I had a mini bag of Fritos for the first time in July. And, I feel better now on a daily basis than I ever did all through college.

Mike Wright

Deep Nutrition and Fatburn Fix reader

I’ve lost over 50 pounds

I’ve lost over 50 pounds. I’m 56 years old. Cutting processed food and unhealthy fats from my diet was one of the first things I did on my health recovery journey...I went cold turkey off the bad oils. Emptied my pantry into the trash and just started eating real food

Mitzi Wilkinson Champion

Knowledge I didn’t know I needed

Your Fatburn Fix book is amazing, my friend. Thank you! I’m an Functional Nutritional Therapy Practitioner and I know my stuff. This is the extra layer of knowledge I didn’t know I needed. Well done!

Jennifer Dillman

Fatburn Fix reader

Lost a solid 20 lbs and my bloodwork is great

I have lost a solid 20 lbs and my bloodwork (after 3 months of eating your way) was even better! I was metabolically healthy (per your book) before I read your book, but barely. Lowering my weight, sealed the deal! I have been talking about you and your book to anyone who will listen...Thank you for all you’ve done and what you continue to do! You are changing lives for the better!

Missy Cramer

FatBurn Fix reader

Lost 20 lbs I could never shed

I love your Fatburn Fix!  Has helped me so so much!  I have had the dreaded weight all my life - 20 or so pounds I could never shed.  I have lost that now. I only eat 2 meals a day lunch and dinner with a glass of milk or cappuccino around 4 to hold me over. No snacking and not bad oils.  It has been the key to unlocking my fatburn.  I work out in the am and believe I am burning fat for energy not from food!

Lauren Smith

http://mcmahonmed.com

I feel great

My waist is four inches smaller. I feel great and many of the minor aches and pains that I had (knees and lower back) are gone. Also, my muscle tone is amazing, even though I have not increased my workout routine.

Richard Janelle

Completed Dr Cate's online course

The go-to for strength and conditioning coaches

Whenever I advise my clients about eating to perform I go straight to what I have learned from Dr. Cate. Her book Deep Nutrition has become the go-to for strength and conditioning coaches across the country.

Kent Matthes

Major League Baseball Agent with WME Sports

Dismantles the lie

Dr. Cate dismantles the lie that seed oils are healthy, which may the biggest lie about nutrition and health because it’s so insidious.  

Ken D Berry, MD

Author of Lies My Doctor Told Me

She knows the chemistry

Dr. Cate alerts us to the harms of seed oils and she’s convincing because she knows the chemistry better than anyone.

Dr. Drew Pinskey, MD

Globally recognized internal medicine and addiction medicine specialist, media personality, LoveLine Host, and New York Times bestselling author

No one is better at communicating nutritional truth

Dr. Cate has had the single greatest impact on how we talk to people about fueling for both performance or durability. While we all are a little unique, the foundational principles of human nutrition are immutable. If you are looking to create a more durable, resilient body, no one is better at communicating nutritional truth than Dr. Cate.

Dr. Kelly Starrett

Physiotherapist coach and New York Times and Wall Street Journal bestselling author

Highly recommend The Fatburn Fix

Dr. Shanahan has had a significant impact on my practice of medicine. I am known as a Low Carb Doctor, but I never really appreciated the negative effects of processed seed oils on the health of my patients. I highly recommend The Fatburn Fix to my patients and have a loaner copy in my waiting room. It is amazing how quickly blood sugars and overall health improves with cutting seed oils. It is not just about the carbs!

Dr. Brian Lenkzes, MD

CEO of LowCarbMD San Diego, co-host of Low Carb MD Podcast and host of Life's Best Medicine Podcast

Respected in the sports world

Dr. Cate reordered my diet when I was with the L.A. Lakers, and the benefits, for me personally, were felt immediately and have served me to this day. I’ve come to take real food so seriously I started a small family farm. I know of no M.D./nutritionist more respected in the sports world than Dr. Cate Shanahan.

Chris Kaman

NBA Player

Brought seed oil issue front and center

Cate brought the seed oil issue front and center. Healthy fats matter. So much so that I created an entire product line to swap out bad fats with good.

Mark Sisson

Founding Father of the Primal/Paleo Movement

Optimal health starts with food

If you want to understand how optimal health starts with food, start with Dr. Cate. Her book Deep Nutrition leaves you with an appreciation of the profound relationship between our genes and the planet, inspiring us to be good shepherds of both.

Dallas Hartwig

Attribution author of The Whole 30

Helped me with endurance

Deep Nutrition really helped me with endurance. I started to feel better as a player. I was able to run more, I was able to be more active …and I just decided to keep going with it to this day.

Dwight Howard

NBA Player

Silver bullet for me

Dr Cate’s teachings helped me lose 60 pounds like it was nothing. It was like a silver bullet for me.

Paul Grewal, MD 

Dr Grewal Internal Medicine, MD, author of Genius Foods

Radically improve your health…

Dr. Shanahan has provided a solid reference that deserves a place in the library of anyone who is seriously interested in nutrition. Her perspective on the vital role that healthy fat has in our diet is novel and, if implemented, can radically improve your health.

Dr. Joseph Mercola

Author of Fat for Fuel and Founder of Mercola.com

Pull up a chair…

I have based my work on the idea that getting the right kinds of healthy fats into your body and avoiding the worst fats is essential to optimal health. I've interviewed dozens of the world's top experts about this, and I know of no one who speaks more eloquently on this topic than Dr Cate. If she’s talking fats, pull up a chair. Take notes.

Dave Asprey

Author of the Bulletproof Diet

The key to unlocking my fatburn

I love your Fatburn Fix!  Has helped me so so much!  I have had the dreaded weight all my life - 20 or so pounds I could never shed.  I have lost that now. I only eat 2 meals a day lunch and dinner with a glass of milk or cappuccino around 4 to hold me over. No snacking and not bad oils.  It has been the key to unlocking my fatburn.  

Lauren Smith

Saved my life

I would like to thank you for literally saving my life. Back in February, I had to be hospitalized while on vacation in Phoenix with an A1C of 11% and had to start taking 2 types of insulin and 2 other meds. I read the Fatburn Fix in April, and followed the program to a tee, and I’m down by 15 pounds, 6.8 A1C, and only one once weekly diabetes medicine. 

Leontyne Tompkins

> Tears of joy

 I'm crying tears of joy and appreciation for all you've done for me and my health! Without Deep Nutrition and Fatburn Fix, I would literally still be in the vicious cycle I'd been fighting all my life! In a nutshell - I am no longer a compulsive overeating addict suffering under the crushing 'thumb' of all food and alcohol.     

Penni Wicks

---

 

The low-carb conundrum just so happens to be an issue I’ve been pondering since reading about the controversy over safe starches. Recently, a couple of pieces of the puzzle fell into place that I think add up to at least one explanation for the debilitating symptoms 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 when 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?

The reason low carbing triggers thyroid changes

In doing research on rT3, I ran into a fascinating article on a group of little-understood compounds called thyronamines (pronounced thigh-row-na-meens). The key to understanding rT3, and unlocking the relationship between carbohydrate consumption and thyroid function, may lie in these newly discovered compounds.

Thyronamines have powerful effects on energy metabolism

Studies performed in 2010 showed that injecting thryronamines into the belly cavity or brain tissues of experimental animals cause the following physiologic and behavioral changes:

• Impaired ability to utilize sugar as an energy source
• Insulin resistance
• Lowered basal body temperature
• Weaker than normal heart contractions
• A marked decline in activity (We can’t ask the lab animals, but presumably, this would be induced by what we would describe as feelings of extreme fatigue)

Sound familiar?

Upon injection, the effects begin within minutes and last 8-12 hours.

And here’s the punchline: Thyronamines appear to be manufactured from that go-to-sleep hormone reverse T3. We can’t yet test you for high levels of thyronamines, but in testing your rT3, we are testing for the precursor of thyronamines. And I expect that, when studies are done in people, we will discover that high blood levels of rT3 do indeed correlate with high tissue levels of thyronamines.

I think this research is vitally important and that we will be hearing more about thyronamines in the future. But we are still left with a very important question that remains unanswered: What do we do about it?

For an answer, we can look to nature and find what I call The bear in the woods theory.

Changing from carb-burn to fat-burn demands new metabolic machinery

The bear in the woods theory suggests that it is the relatively sudden change from high carb to low that flips the switch.

Bears are omnivores, just like humans. And, of course, bears hibernate. Understanding the variations of a bear’s diet throughout the year helps us to understand why biology has built into our mammalian metabolism a sensitivity to changes in carbohydrate consumption.

Imagine you are a bear living in Yellowstone national park. It’s late summer, and the salmon runs are gone, the grazing animals born in spring have now grown too fast for you to catch, the grubs under the rocks are all hatched, and pretty much all that’s left, aside from campground garbage, is nuts and berries. Plucking ripe berries off a bounteous shrub is far easier than cracking nuts, so you gorge on berries. In a few weeks, though, the berries are gone, and there’s very little food left. That’s okay, because the abrupt decline in carbohydrate consumption is accompanied by increased reverse T3 and increased production of thyronamines, which makes you feel exhausted. Thanks to all the weight you gained, you are now so well-padded with cushy fat that you think you could just crawl into a cave somewhere and sleep for a long, long time.

Research in humans shows that, just like bears, our thyroid hormones are influenced by major changes in the amount of carbohydrates consumed.

For some, an abrupt decline in available glucose may trigger an atavistic hibernation reflex, which will trigger the conversion of a thyroid hormone called T4 into something other than the normal T3, namely into the reverse form, rT3. rT3 then gets converted into thyronamines and causes all the symptoms of low thyroid function without significant deficiencies of thyroid hormone showing up on lab tests, leaving people to worry there is something incredibly wrong with their hormonal function.

 How do you enter fat-burning mode without going into hibernation? The solution is gradual change.

If you have gone low carb successfully, you have accomplished a major change in your metabolism, one that involves turning on scores of enzymes your body has not needed or used for a long time, decades in some cases. Not everyone can accomplish this overhaul in time. Those who can often continue low carb for life with great success. But those who cannot accomplish all the necessary changes flip the hibernation switch, and increase production of rT3 and thyronamines, which causes crushing fatigue and may lead to intense carb cravings in order to turn off the hibernation switch again.

For these people, an easy way to avoid flipping the hibernation switch and reduce carb cravings may be to simply make a more gradual reduction in carbs rather than an abrupt one.

Atkins, who advocates an abrupt switch to less than 20 gm per day, seems to have been aware of this problem, and in fact, in his writing, he warns people they may experience fatigue in the first few days or weeks after going very low carb. Unfortunately, for some people, the fatigue never improves, and they give up on low-carbing altogether.

 Instead of giving up, I believe you can try again but next time don’t go cold turkey on carbs. Cut back gradually.

Incidentally, none of my patients reported feeling worse when they went low carb. I suspected it had something to do with the fact that I introduced them to low carbing one meal at a time beginning with breakfast. I made this recommendation simply because I didn’t have time to go over everything with them in one visit. I only had time to give them ideas for one meal, and had them start by cutting carbs from breakfast because that is the time of day we are most able to switch our dormant fat-burn enzymes from off to on.

Bottom line: If you jump into the Paleo (or any low-carb) program and hit a brick wall because of side effects, instead of giving up on low-carbing for good, add back your carbs until you feel better again and then try cutting down again, but go slow to give your body the time to adapt to the idea. This way, your low metabolism can gear up to give you the fat-burning benefits of hibernation without having to take the four-month winter snooze.