Fasting and Metabolic Damage

During fasting thyroid function becomes severely dysfunctional.
Not only does free T3 drop but reverse T3 rises. This is the worst case scenario. Reverse T3 (rT3) is not even looked at by most doctors so you may have normal TSH/T3 but still present as hypothyroid. You can still be having all the negative symptoms like difficulty losing weight and extreme fatigue yet the doctor will tell you it is all in your head. 
Reverse T3 is a disposal form of the active thyroid hormone. When fasting or calorie restricting, it builds up and blocks receptor sites so that any active T3 cannot get into the cells. This essentially disables thyroid function and shuts metabolism down to Just enough to keep you alive but slow enough not to have any weight loss. This is how people can fast and lose little to no weight. Those that do lose some weight often see it come back as soon as they eat again. This is because all they lost is mostly water weight. 
This is a life preservation system. If this didn’t happen you would die of starvation very rapidly when food is not available. Your metabolism would keep running on high and you would quickly consume all your muscle and then your organs. If metabolism stayed high you would continue to use glucose for the cells that need it at a high rate and this requires either glucose coming in or it will use your protein (muscle and other tissue) to fuel gluconeogensis to make glucose. Your body shuts down metabolism to a bare minimum to keep you alive as long as possible in order to survive through the starvation period. It does this to save you and there is a cost. It saves your life but it does damage to your thyroid and metabolism. Doing it enough will do permanent damage and this is why so many women are having to take thyroid medication now and so may more are suffering the symptoms but are yet to be diagnosed. Once doctors start testing and understanding the role of rT3 I think we will see the number of diagnosed cases rise dramatically. 
If you look at the most prolific promotors of fasting in the keto community they are:
Jason Fung: Has admitted publicly, though Megan Ramos (Director of IDM), that they do not fast people more than 24-36 hours except in extreme cases and only under strict supervision. They ensure it is safe by check their blood work constantly to ensure safety. He himself does not do extended fasts on a normal basis . This is a video where Megan Ramos (Director of the IDM clinic) admits that they rarely do any fasts beyond 36 hours. She changed her presentation based on a presentation against fasting given by Stephen Phinney which I speak about later. 
Listen to this talk. This is how fasting can be done safely. In clinic. With supervision. She discusses the very key aspects of doing this safely and that includes diagnosing issues that may be problematic like former eating disorders, obsessive behavior and bullying from weight issues. All of these can lead to obsessive fasting which can be extremely dangerous. I still don’t think it is necessary but if you really want to do it, do it in a clinical setting where you can be led safely through it. This is not something that anyone should ever do on their own.
Jimmy Moore: Jimmy wrote the book “The Complete Guide to Fasting” which recommends fasts as long as 21 days and more. People doing this level of fasting on their own is something that Dr. Fung would never recommend. It is not only stupid but dangerous. Blood should be checked regularly in order to assure there is no danger of any nutrient deficiency. Dr. Fung does this in clinic but all those at home doing this as recommended by Jimmy do not. This is unethical .Jimmy has gained back massive amounts of weight and despite his continued dedication to fasting he can no longer lose weight. He blames this on “Metabolic damage” and he is right. This is caused by his continued fasting and nothing else. He successfully lost 170lbs around the exact same time I did using Atkins just like I did. I believe he started Atkins in 2004 and I started in 2005. We both followed the 20g per day initial phase of the program fro the whole time we were losing weight and didn’t cut calories. We both lost massive weight. If his reason for not losing weight is metabolic damage from when he was obese the first time why was he so easily able to lose it then but now he can’t? The reason is because he has caused his current metabolic damage by continuing with these extended fasts. 

Like Jimmy, I was insulin resistant, I was poor, I was sick and I was obese. I was metabolically damaged yet I am still able to maintain my weight loss and continue to lose weight year over year. Why? I don’t fast and I don’t calorie restrict. That is it. Other than that we had the exact same experience. 

Lets look at what fasting has done for Jimmy:

It has gotten worse. If fasting was beneficial should he not be getting leaner with all the many multiple day fasts he is always doing? He appears to be getting more metabolically damaged not less. Why can’t he see it?

I read Jimmy’s book. Primarily because I thought it was written by Dr. Fung. It turns out it was written by Jimmy and made to look like it was written by Fung. Fung was only a contributor. When I read the book I implemented the recommendations.

I started the year at 214lbs. I did extensive fasting periods. Way too much from what I now understand. I likley spent 3/4 of an entire year in a fasted state with alternate day fasting and numerous extended fasts ranging from 3-5 days. I ended that year at 215lbs. Really beneficial right?

The only time I had this type of results when I was doing paleo and eating 1500 cals a day. Complete stall. This past year I have not missed a single meal. I have also spent 42 days eating 5,000 calories when my normal intake is approximately 2500 calories. I started this year at 215lbs and I am currently sitting at 195lbs consistently. My lowest weight in 6-7 years and I also have the most amount of muscle mass I’ve ever had. With no fasting.

Carl Franklin (Two Keto Dudes): Carl often talks about the latest extended fast he is doing. From 7-14 days is what he refers to mostly. He is also still obese and can no longer lose any weight. Despite his constant fasting. How can a person not eat for 14 days and not lose weight? Extreme metabolic damage. How does one cause this? By shutting down their thyroid with fasting. He has now gotten himself to a point just like Jimmy where he can no longer lose weight no matter what he does.

Luckily Carl has not gained any weight back but he clearly is not having any success in losing anything with his continued fasting. Why continue to starve yourself if there is no measurable effect? Yes he lost alot of weight but at 297lbs he is still obese and is now stuck and cannot seem to lose anymore. From what I understand he didn’t start fasting until late into his weight loss.

The one common factor in every person I work with that is having a hard time losing is thyroid function and that they have a long history of calorie restriction and fasting.
It is a clear fact that low calorie drops metabolic rate. What is the most extreme version of calorie restriction? Fasting.
Here are some articles I wrote with links to studies showing the fact that caloric restricting and fasting lowers thyroid function:
Here is a video by Dr. Stephen Phinney Discussing why he disagrees with fasting. I don’t agree with his estimates on lean mass loss and there are lots of reasons I don’t think it is accurate but mainly because the physiology dictates that lean mass preservation is taken as priority. What he is using as an extrapolation is what very active people see when fasting and only in the short term. The act of the body shutting down thyroid decreases the amount of lean mass losses. You will still lose lean mass though. There will always be a need for some glucose so if you are fasting you will need to get that from somewhere. Some of it will come from autophagy (breaking down of unnecessary/defective tissue) which is why it is said that fasting is good for autophagy, but some will still come from lean mass. For me that part that is bad is the thyroid shutdown and the more fasting you do the more damage you do.
Lastly I want to discuss something that someone brought up in the facebook group.
“But I know people that do long fasts and they feel great. They are full of energy and don’t feel cold. How can it be true that thyroid function drops?”
Lets look at what happens in fasting:
1. Caloric intake stops. Insulin and blood sugar drops.
2. The body continues to use glucose to fuel the tissues that need it.
3. Thyroid starts to down regulate metabolism to preserve lean mass
4. After a full day all possible glycogen stores are gone and blood sugar starts to get very low.
5. This causes an increase in cortisol in order to trigger gluconeogenesis to keep blood glucose stable and prevent hypoglycaemia.
6. Epinephrine and adrenaline are also released as a result of the low blood glucose. These are the reason people get surges of energy and clarity when fasting. Especially in later stages like day 2 and 3. This is for one reason and one reason only. To give you the energy and mental clarity to HUNT AND GET FOOD!!!
This whole process is one of survival and not one of some magical fountain of youth or magic healing process. It is survival of the fittest and nothing more. It is the body doing everything to keep you alive long enough to eat again. No animal in nature is foolish enough to purposely go without food. Except humans.
Our ability to use science to dig into the mechanisms of how the body reacts to eating or not eating is amazing but it is also our greatest enemy. It led us to “fat is bad” and “eat less and move more”. Two of the greatest mistakes of our time and now it has led us the next great mistake. “Fasting is good for you and will help you lose weight!”
Don’t let this next big mistake ruin your thyroid and your ability to get healthy and maintain that health. Just eat the right foods and enough of it to keep your body functioning properly and the weight you lose will stay off rather than creeping back like it has for so many others.
Keto ON,
Coach Jack

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