Calories are an important part of maintaining your weight, but they aren't nearly as important as you think if you have thyroid-related problems.
Thyroid patients should consider themselves in a unique category which means they must understand how their thyroid functions which will then allow them to understand how various diets impact their weight.
Let's discuss how calories impact your weight, your thyroid, and how you can really lose weight.
- Calorie restriction (or counting calories) can negatively harm your thyroid and ultimately lead to weight gain, even if it works temporarily.
- Weight gain in hypothyroidism is driven by your hormones and not by calories.
- You should match your calorie consumption to your metabolic rate (and to do that you must rely upon your appetite).
- There are certain conditions which confuse your appetite and must be treated for long-lasting weight loss.
How Calories Impact Your Thyroid
I've been fairly clear on this topic but I wanted to go into it in more detail.
One question that I get asked very frequently on this blog and in the comments section has to do with how many calories should be consumed if you have hypothyroidism.
The question goes something like this:
"I've been told by my doctor to eat only 1,200 calories per day to lose weight. Is this enough if I have hypothyroidism?".
You can pretty much substitute out the 1,200 calories with any other amount as well.
I'm going to give you a quick answer here now, and then I'm going to have to explain the answer because you aren't going to like it.
The truth is that you should NEVER reduce your calories if you have hypothyroidism for any reason.
Because calorie reduction, especially in hypothyroid patients, will result in the combination of 'metabolic adaptation' and 'thyroid damage'.
The term 'metabolic adaptation' is the actual scientific name for what occurs during calorie restriction (1).
Under persistent calorie restriction, your body responds in a number of ways:
#1. It reduces your Free T3 dramatically (18 weeks is enough to drop your free T3 by as much as 66% (2)) - This is obviously incredibly important because T3 is the most active form of thyroid hormone in your body and free T3 is directly correlated with your ability to lose weight and keep it off.
#2. It increases your reverse T3 by as much as 27% - 50% (3) - Reverse T3 is the marker that your body creates when it is under stress and when it can't convert T4 into T3.
High levels of reverse T3 slow down cellular thyroid function.
#3. Your free T4 levels may stay the same or increase (4), most likely owing to a reduction in T4 to T3 conversion.
#4. Your overall metabolism will drop from metabolic adaptation.
#5. Your TSH may stay the same or actually get lower (5) - This may sound good at first, but the fact that your TSH does increase is probably due to the fact that your hypothalamus is being suppressed and can no longer produce TRH which stimulates TSH.
This is also probably why most doctors fail to recognize the impact that calorie restriction has on the thyroid because they are so focused on the TSH (often to the detriment of the patient!).
With all of this information in mind, let's dive into some more information about calorie restriction, weight gain, and how it all fits together.
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What Counts as Calorie Restriction?
So, how do you know if you are reducing your calories and how much is 'enough'?
The answer is that it depends on your body and on your thyroid function.
Your thyroid controls (at least in large part) how many calories you burn on a day to day basis.
So, while the thyroid controls your metabolism, it's important to realize that pretty much every single person with thyroid disease suffers from thyroid issues to varying degrees.
If we took 100 thyroid patients and measured their metabolic rate (how many calories they are burning on a daily basis) what do you think we would find?
Do you think that we would find that every single person is burning the same amount of calories each day?
Do you think that we would find that each person has identical lab tests?
Again, absolutely not.
We would find a great deal of variance among those individuals and we would find that the needs of EACH of these patients are different!
The number of calories they consume each day would closely mirror the number of calories they burn each day (which is based on their metabolism) and this would be correlated with their thyroid function which is dependent upon how much thyroid medication they are taking.
How on earth does it make sense to give the same recommendations to all 100 patients if they are all so different?
It doesn't at all, and that's the problem.
Each person deserves their own individual recommendations and advice.
So, while that is obviously the best way, it's also not practical in this blog post.
Instead, I'll give you some basic information that you can work with.
In general, you want to avoid ANY diet which seeks to 'work' by requiring calorie restriction in any way, shape or form.
But please note that when I discuss calorie restriction I am talking about sustained daily calorie restriction over a period of 3+ weeks (or 21 days straight).
Prolonged and intermittent fasting, while they are forms of calorie restriction, do NOT cause the same damage to your thyroid or metabolism (unless they are done in excess).
This could include, but is not limited to, diets which have any of the following:
- Restrictions on the number of calories you can consume at each meal
- Restrictions on the number of calories you can consume throughout the day
- Restrictions on your portions at each meal
- Diets which entail extreme workouts
- Diets which promote a specific amount of calories that should be consumed based on generic information such as your gender, height, weight, etc.
If this information isn't enough, then you can also see a list of diets which would fit into these examples below:
- The hCG diet
- Weight watchers
- Virtually any other diet which recommends limiting your food intake or counting your calories
Not included on this list would be diets which cause a natural reduction in calorie consumption through their impact on hormone balance or appetite hormones.
This could be diets such as the ketogenic diet which may cause natural calorie restriction.
I'm not a fan of the ketogenic diet in general, and you can read more about my thoughts on this particular diet here, but it would technically be 'approved' and can be potentially helpful for some thyroid patients.
Why Thyroid Patients Really Gain Weight
To further push the point that home that calories do not always correlate with weight gain (or weight loss), let's look at some of the reasons why thyroid patients gain weight.
It may appear simple, but it's actually a little more complex than you might think.
As your thyroid function falls, you would expect your metabolism to drop as well.
We see this in thyroid patients because, as every thyroid patient knows, when their thyroid is low they will almost always notice weight gain.
But, here's the big problem.
If that's true that hypothyroid patients gain weight when their thyroid is low, which it definitely is, why then do they not lose that weight once they start taking thyroid medication?
If that thyroid medication is 'normalizing' their thyroid function, wouldn't we expect that weight to come off if it's related to their thyroid?
We would, and why it doesn't is a complex and confusing topic and something I refer to as the thyroid weight gain paradox or thyroid obesity myth.
Important to this discussion, but something we won't spend time on, is the fact that most thyroid patients are undertreated due to the current thyroid treatment paradigm (but this still applies to thyroid patients who are adequately treated with thyroid medication).
What this means is that there is some other factor which is ALSO influencing weight gain in thyroid patients which is independent of their thyroid and not necessarily associated with the calories that they consume.
My belief is, which is born out in my weight loss case studies, is that the other factor we are missing here is the impact that your thyroid has on other hormones in your body.
Thyroid dysfunction causes a cascade of hormone imbalances which are not 'fixed' with the proper replacement of thyroid medication which results in persistent weight loss resistance even in the face of thyroid medication.
You can see documented examples of how your hormones obviously impact your weight with these examples:
- Studies show that patients who undergo thyroidectomy (even with thyroid replacement) gain up to 20 pounds on average and typically can never lose it (6)
- Studies show that women who undergo menopause gain on average 15 pounds (7)
- Women who have their gallbladder taken out gain weight (8).
- Women who have their uterus removed gain weight (9).
- Women who start insulin for diabetes immediately gain weight (10).
Do you think it makes sense that these women suddenly changed the number of calories that they consume right after their surgery?
Or do you think it's more plausible that these surgeries impacted their hormones which then impacted their weight?
And women who fall into this category will never have success with calorie-restricted diets (the answer from doctors) because it doesn't address the problem that they are facing which is hormone imbalance.
In fact, if you calorie restrict, in these settings you will often cause further issues as you drag your thyroid down which also drags down other hormone systems.
The answer? To ensure that you address the main problem (your hormones) and not the number of calories that you consume.
You can read more about how each of these systems contributes to weight gain and how to treat them below:
- Weight gain induced by cortisol
- Weight gain induced by insulin resistance
- Weight gain induced by leptin resistance
- Weight gain induced by low testosterone
- Weight gain induced by menopause (and other sex hormone imbalances)
- Weight gain induced by low thyroid function
How Many Calories Should You Eat?
The next logical question you should be asking yourself is how many calories should I consume?
And the answer is actually relatively easy to answer.
You should be consuming the same amount of calories that your body burns on a daily basis.
Whatever your metabolism is (or resting metabolic rate or resting energy expenditure is) you should match that with the food that you consume.
The good news is that your body has a built-in mechanism to help you do just that.
It's called your appetite.
Your brain will tell you when it's time to eat (unless you have certain conditions listed below) by inducing hunger!
As long as this system is working correctly, you will only be hungry when your body needs fuel and energy.
And your hunger will subside once you consume enough food!
It's quite a simple system.
If you are consuming fewer calories than your body needs then your body will send signals to increase your hunger.
But what happens if you ignore those signals?
That's when the problems arise.
If you do not respond to the hunger, for an extended period of time, then your body may start to alter the number of calories that it consumes by reducing your metabolism.
If you persist with your calorie restriction this lowering of your metabolism will continue as well and eventually you will be in a state where you are burning far fewer calories than you used to on a day to day basis.
If you don't believe me, you can take a look at perhaps the easiest to understand study on this very topic.
Contestants of the biggest loser were studied both before and after their weight loss journey by evaluating their metabolism.
Researchers found that after their weight loss and dieting efforts that, on average, each contestant was burning up 400-600 calories LESS than they were before they started.
And the worst news is that this damage persisted for about 6 years afterward (11).
Let's put this into context so you get a better idea of how this can impact you.
Imagine, hypothetically, that under healthy conditions you are burning 2,000 calories per day.
You also have hypothyroidism, however, and it's not being treated correctly so instead of those 2,000 calories you are burning somewhere closer to 1,800 per day.
Because of this, you are gaining weight and you'd like to try and lose weight.
So you decide to cut your calories down to 1,400 calories per day and you do this for 30 days.
Initially, you start to lose weight (maybe 5-10 pounds) and you feel great.
You keep this weight off even though you increase your calories back up to 1,800 to 2,000 per day.
Eventually, though, as it almost always happens, you regain your weight back after about 6 months.
You want to fight this weight gain so you think to yourself that you're going to get aggressive and lose this weight fast by doing what you did previously, only this time you are only going to eat 1,200 calories per day.
What happens this time?
Instead of losing the weight like you think you will or should, you only lose about 2-5 pounds and it takes 60 days instead of 30.
But this time once you increase your calories you regain all of the weight you lost plus some extra.
Now you are an extra 5 pounds heavier over this 6-9 month period and confused.
So what happened?
The answer is simple, your body 'adapted' to the caloric restriction by reducing your metabolism which resulted in your weight gain.
You would have been better off testing for and addressing the hormone imbalances that were actually causing your weight gain, to begin with, such as your undertreated thyroid.
This vicious cycle is why there are so many women (and some men) in the thyroid community who simply can't lose weight.
Conditions Which 'Confuse' Your Appetite
Unfortunately, it's only possible to rely upon your appetite if you can trust that your appetite accurately reflects how many calories your body needs.
Under normal conditions, it does.
But under other conditions, your appetite may actually fool you.
It's possible for your appetite to be greater than it should be due to a variety of factors.
This can make matching your calorie consumption to your appetite quite difficult (but not impossible)!
The following conditions are known to cause conflict with your appetite which may result in you eating more than you should:
- Leptin resistance (12)
- Eating disorders (predominately binge eating disorder)
- Certain prescription medications (13)
- Cortisol abnormalities (14)
- Depression (15)
- Certain gastrointestinal disorders (16)
- Pituitary/Hypothalamic disorders (17)
The presence of any of these conditions may cause difficulty if you are trying to match your calorie intake to calorie consumption.
They can and should be addressed first, which may but your weight loss on hold, but will allow you to not only lose weight in the future but keep it off long-term.
This is, after all, the best way to approach weight loss in thyroid patients, a layered, comprehensive approach.
The bottom line?
If you have hypothyroidism then you should absolutely avoid calorie restricted diets as they not only harm your thyroid but also cause long-term damage which can last for years and years.
The key to weight loss is to address underlying hormone imbalances that exist in your body first while also addressing and treating your thyroid with the right balance of T4 and T3.
I know it is tempting to try and cut your calories for quick weight loss! I see it here all the time.
But I'm warning you not to do it as it will only cause weight gain in the long-term and even more difficulty with weight loss in the future.
As you take this approach you will find that you are not only able to lose weight but keep it off.
Lastly, if this approach resonates with you, you can always find more information on my approach to weight loss (including a list of advanced therapies) in my weight loss guide.
Now I want to hear from you:
Have you been restricting your calories?
Do you believe you are suffering from metabolic adaptation or a damaged metabolism?
What have you done to help with weight loss?
Leave your questions, comments or concerns below to keep the conversation going!
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