Thyroid and weight
A different way to look at how they go together
I get many people in my practice with thyroid imbalances, but let me say this.
Patients over diagnose themselves with thyroid disease. This means more people convince themselves they have thyroid disease than have actually have it.
Don't get mad at me.
Keep reading.
Now let me say this.
Physicians under diagnose their patients who actually have thyroid disease. This means more people have thyroid disease than are actually diagnosed by physicians.
The reality as I see it is that it falls somewhere in between what patients believe and what physicians find.
One of the most common complaints I hear in the office is:
" I keep gaining weight. I think it is due to my thyroid."
While thyroid is involved in metabolic weight control there are some nuances.
Let me explain how I see it and you can let me know if you agree or disagree in the comments section.
Thyroid hormone, more specifically Free T3 (FT3), is involved in metabolism which for this post I will simplify as the burning of fuel for energy. From testing this hormone for many years I have found FT3 correlates very very closely with the amount of dietary carbohydrates consumed which are then burned for energy. I hopefully will get more into what that means in the future, but for now let's just go with you need thyroid hormone FT3 to function normally to have a well balanced metabolism.
Sneak peek at a future post:
FT3 lab values so closely track with dietary carbohydrates consumed and burned that I call it my Dietary BS detector. Yes, when I write BS that is what I mean. I can usually look at the FT3 and determine what your body is burning for energy based on what you are actually eating. I used to call it my stupid doctor trick but that did not sound right.
Now let's look at what I call my IMW 10-10-10 rule of thyroid balance.
Scenario 1:
Assuming you have a normal functioning thyroid gland.
There are 30 days in a month.
Let's suppose you overate 10 days of the month, ate normally and well balanced 10 days of the month, and under consumed 10 days of the month. This is actually fairly common but it could also be you overate 5 days, under consumed 5 days, and ate well balanced for 20 days. The key to understand this mechanism is that the days you over and under consumed are equal which should then equal out to weight stability.
On the days you overate you would most likely have gained weight, let’s say 1/2 lb a day. 10 days x 1/2 lb = 5 lb weight gain those 10 days.
On the days you ate normally your weight would not have changed.
On the days you under consumed you would most likely have lost weight, let’s say 1/2 lb a day. 10 days x 1/2 lb + 5 lb weight loss those 10 days.
So if this is how you eat on average throughout a 30 day period, and you have a normal functioning thyroid, your weight at the end of the month would be neutral, no loss or gain. 10 days of overeating would balance out with the 10 days of undereating.
5 lb weight loss is balanced by the 5 lb weight gain.
Scenario 2:
Assuming you have an underactive or slow functioning thyroid gland.
There are 30 days in a month.
Let's suppose you overate 10 days of the month, ate normally 10 days of the month, and under consumed 10 days of the month.
In this scenario on the days you overate you would have gained weight, just like with a normal functioning thyroid. You would most likely have gained weight, let’s say 1/2 lb a day. 10 days x 1/2 lb = 5 lb weight gain those 10 days.
On the days you ate normally your weight would not have changed, just like with a normal functioning thyroid.
Now, here is where I see the difference. On the days you under consumed you would NO LONGER have lost weight.
If you have a slow or underactive thyroid gland, the difference between the two scenarios, Normal vs low functioning thyroid (hypothyroid), is that you do NOT lose weight even if you under eat.
If this is how you eat throughout the month and you have a slow or lower functioning thyroid, your weight at the end of the month would be higher.
So if this is how you eat on average throughout a 30 day period, and you have a lower or hypo-functioning thyroid, your weight at the end of the month would be 5 lbs heavier
10 days of overeating would NO LONGER balance out with the 10 days of undereating in a hypothyroid state.
So the question then becomes:
Doesn't that mean that having an underactive thyroid caused me to gain weight?
The actual answer is NO, but with some nuance.
If you reread the scenario, having an underactive thyroid did not cause you to gain weight different than in the normal thyroid scenario. What it did do was NOT ALLOW you to lose weight when you under consumed. Not losing the weight when undereating no longer allows you to maintain the weight neutral balance from when you do gain weight from over eating.
It’s a nuance but a important one that I see all the time in my practice.
I believe many overweight people do NOT have slow metabolisms. They are just stressing their metabolic balance and the body shifts from a balanced burning and storing metabolism to more of a storing metabolism. More on this in a future post. When we switch to a Ketogenic style diet, the metabolism usually shifts to more burning and less storing, so fat/weight loss usually occurs.
When does this not occur or have trouble occurring?
If someone is truly hypothyroid, they do not lose the weight when they are under consuming, but since they are no longer overeating on a keto diet, they remain weight neutral. Evaluating the thyroid hormonal and metabolic systems/axis can be very helpful in pinpointing if there is an issue here and can be a cause of lower carbohydrate/ketogenic diet failures in losing weight.
I will discuss more about how the IMW looks at thyroid lab evaluations in a future post.
Very interesting and makes sense to me.