If I could summarize what I’ve learned over the past five years as an RD and now an NP working with women that fall somewhere on the eating disorder or disordered eating spectrum, it’s that they know a lot about food and calories and nutrients, but very little about what their behaviors actually do to their internal body.
Ever since my first job as a dietitian back in the summer of 2012, I have had a deep fascination with the thyroid gland, second to the female reproductive system. This little gland does so much. I could write for hours about all the things that affect thyroid function, but what I hope you learn at the end of this post is how inadequate nutrition affects thyroid health and what that means for you.
From a physiological standpoint, thyroid hormone plays a huge role in metabolism. It plays many roles and acts on nearly every cell in the body, but one of it’s main roles is regulating metabolism. You may have seen your doctor draw a TSH lab {thyroid stimulating hormone} but there are several other thyroid hormones. It goes a little like this:
Your pituitary gland makes TSH and that TSH tells your thyroid to make thyroxine {aka T4} which is an inactive thyroid hormone that has to be converted to its active version before it can be used by the body. That active version is triiodothyronine aka T3. Stay with me here with this next part. T4 can be converted to T3 {the active version with metabolic effect} or reverse T3 — an inactive form that actually blocks cell receptors, thus blocking the effect of T3. All that to say, I know the practice guidelines in medicine/nursing say order TSH first, and then if that’s abnormal order additional thyroid labs. But I hate that guideline, because a normal TSH doesn’t rule out other thyroid abnormalities.
So now that we know more about the thyroid and thyroid hormones, how does undereating in any form affect your thyroid?
When it comes to dieting, detoxing, restricting foods groups or any sort of restricting eating – that stuff wreaks some havoc on your thyroid, even in short amounts of time. Studies show that even three weeks of calorie restriction causes a substantial reduction of T4 conversion to T3 {the active one} — what’s even more important is that TSH levels are not always elevated. Typically, if your TSH is elevated then doctors go searching for low levels of T3/T4. My whole point being: a normal TSH doesn’t mean you always have normal T3/T4.
When your body experiences lack of food or abundance of food, your thyroid adapts to adjust metabolism and other bodily processes in order to maintain homeostasis. It’s when the body is forced to acclimate to dysregulated eating patterns over a long period of time when things get a little dicey and the thyroid isn’t as adjustable. And then it starts to putter out.
Sometimes that’s due to inadequate nutrients needed to produce and convert thyroid hormone, or abnormal cell signaling due to the reasons I talked about with reverse T3, and lastly and what I think it most notable…sometimes it’s due to elevated levels of stress hormone called cortisol in the body. And cortisol inhibits the proper function of thyroid hormone.
Other sources of stress beyond nutrition (which includes insufficient calories or carbs/fats/protein or mircronutrients) include too much exercise, too little sleep, emotional/mental stress.
Think of low thyroid hormone = things slow down. So beyond fatigue (classic in cases of hypothyroidism) other symptoms include constipation, poor digestion, depression and feeling cold all the time.
I don’t think medications are the devil, I do think there is a time and a place for medication and they can be helpful as an adjunct to lifestyle. But often (not always) medication in these cases is not appropriate, nor helpful. Because if you flood your body with synthetic thyroid hormone it won’t be able to recalibrate and readapt to normal. It’s the lifestyle stuff that is so so important. Nourishing your body, sleeping enough, self care to reduce stress, and moving your body in a way that’s healthy for you.
When I had hypothalamic amenorrhea, I also had normal TSH and low T4 levels. So unless I would have insisted in getting the full thyroid lab panel done, I would have never known. Even more important I think is that all this is reversible, the body can heal. So what I hope you remember after reading this post (that I hope isn’t confusing) is that often, there are many lifestyle changes that can help tremendously in healing low thyroid levels.
And I think the fact that the body can reverse damage when we take care of it is pretty cool.
I am so glad you wrote about this. Not enough women understand the hormonal consequences of restrictive eating habits. I work with a lot of women who’s metabolisms aren’t functioning properly and it takes a lot of time and patience to get them to full speed and to get their hormones in order.
Thank you for this article! Early on in recovery, reading about the science behind eating disorders and why you exhibit physical symptoms like being cold, tired, bruising often helped me through the initial stages of recovery. Now, as I continue to move forward I find it comforting that my body is healing from the damage, and it makes me appreciate what my body does naturally! I would love to read more articles like this one, or more about the set weight point theory because I still can’t quite get that one through my head.
I will write as much as I can – so glad it has been helpful 🙂 xo
I have never had an eating disorder per se, but I have had disordered eating in the past. For the past couple years though I have been trying to take care of myself better and eat “normally”. However, I have exhibited those symptoms you described: fatigue, constipation, always cold, etc. I went to my doctor this past February and asked to have my TSH, Free t3, and free t4 checked and they said everything came back normal! I am glad of course, but it was a little frustrating because I don’t know why I still have these symptoms then. I feel like my doctor brushed off my concerns since my tests were normal. I guess there isn’t a point to this – ha! Just wanted to say this type of stuff is interesting, and it is neat to see it from your perspective now as an RD and NP.
so glad it’s been helpful! you’re body can compensate for a while and keep levels in range despite symptoms so that doesn’t mean things couldn’t change soon…I hope thats helpful! xo
Hi robin!
How does soy effect our thyroids. I’ve been drinking soy milk for the last month or so and just have seen some research about its negatively effecting thyroid function.
I would be interested in your view on soy, too! In relation to thyroid, but also in general. I eat a lot of tofu and keep thinking I prob shouldn’t? This was an awesome post!
soy is not the devil….I think rotating it into your diet occasionally is completely fine – the studies are still inconclusive. hope that helps!
It is incredible how the body can reverse and heal; it’s such a testimony to how God heals. I definitely felt the things that you mentioned, poor digestion, being cold, and such after struggling with an ED for several years. After a while of just eating more, exercising less, and such, I think I’ve seen a huge difference in my metabolism.
A few months ago after a blood lab result for my allergies, I got word that my TSH levels were normal but my thyroid antibodies were actually really high. So this is so relevant for me right now though I’m not sure if this completely explains my thyroid issues. But it’s crazy that I learned more from this one post that I did during my appointments with the endocrinologist. Thanks, Robyn!!
I’m so glad it was helpful kaylee! if your antibodies are high you’re perhaps dealing with an autoimmune issue.
Really interesting- Thanks! I would love to hear your thoughts on Hashimoto’s as well. I got diagnosed with hypothyroidism when I was 11, when I developed a goiter. Sometimes doctors call it Hashinoto’s, and others just refer to it as hypothyroidism. I always thought since I developed it so young that it is more of an autoimmune issue. Anyway-I would love to hear your thoughts on the difference between Hashimotos and hypothyroidism, and if just because I have taken Synthroid since I was 12 if I will always have to take it (doctors don’t usually explain very much). Thanks!!!
I was diagnosed with the same thing at 22 years old. I have the same question as you, and am wondering if I’ll have to take synthroid for the rest of my life. I asked a recent doctor if it was possible to eventually go off the drug and her response was basically “no you’ll be on it forever. Lifestyle doesn’t affect it much.” (!?)
I started synthroid at around 11 too and i’m 27 now– 5 years ago my bloodwork came back normal and i’ve been off it ever since! lately I’ve been feeling a bit off, so i had it checked, and apparently i’m “subclinical” so it was my choice to get back on synthroid or not. I’m back on it but haven’t noticed much difference. its an extremely low dosage
hope my response helps!
I hope my response to Caitlin helps! <3
We use to treat Hashimotos with lifestyle all the time when I worked with an endocrinologist in VA — Hashimotos is autoimmune so lifestyle treatment is focused on boosting the immune system..we took people off meds all the time with Hash so I hope that brings hope 🙂
I know docs say you’ll be on it forever, but that is simply not the case. But it does take some time and education and really supporting a patient as they apply the lifestyle changes. Hope that helps!
Thanks! That was really helpful- thanks for taking the time to respond 🙂
Did you work at an endocrinologist in Charlottesville? I ask because I live in Washington DC. I’ve never had ANY doctor tell me I could treat Hash with lifestyle so if they are close to Northern VA please let me know!
Thanks! I have Hashimoto’s and wondered if this information applied to it. Are you familiar with a gluten free diet being prescribed for Hashimoto’s? I have a friend who went gluten free to “treat” her H.’s yet my doctors over the years have never ever mentioned doing that –to my relief, ha! But then I was never symptomatic. Just got diagnosed after routine blood work.
I couldn’t have agreed more when you said these women know so much about nutrition and calories but not what it does to your internal body! I loved learning a little more on this subject.
Robyn, praise your good sense to address this underappreciated topic! There is an unfortunate dearth of information accessible to the layperson on understanding the thyroid, and particularly how one’s own actions can correct and optimize function. All too often traditional doctors will suggest quick fixes rather than evaluating and educating patients on how they can take ownership over their own health. Too many women misunderstand how the choices they make – hourly, daily, and over the course of the waves of a lifetime – can have a profound impact on this control center. This introduction is an insightful overview and I welcome any / all additional information you are willing to share with us on this subject.
Thanks so much for this post! What are your suggestions on how to reverse low thyroid (without medication) ?
thats something we work with nutshell clients on all the time and really individually based so I want to protect what we do at Nutshell – happy to help if you want to reach out though 🙂 <3
Grateful for people who know more than I do and can communicate it in ways that are understandable and helpful! I was diagnosed with hypothyroidism while still struggling with disordered eating several years ago and was put on armour thyroid. I am now taking care of my body, feed it well, and my period has returned. Are you saying it is possible that I may not need medication in the future? If my thyroid function has improved, would we expect to see elevated levels of T3? Thanks!
absolutely you likely will not need meds if you are taking care of yourself! all your levels should be in range if things are working well
You did a good job of explaining it simply and informatively. What do you think about adrenal fatigue and thyroid issues. It seems like they can have similar symptoms. Can you have a normal TSH, T3, and T4 but still be overly stressed and / or have adrenal fatigue?
yes yes yes
Great post. And just like doctors throwing birth control at you to cover an underlying problem, the same thing was done to me with regard to thyroid meds. They did blood work and determined I have hypothroid issue, which they wanted to me on drugs, but my BMI was so appallingly low, they never said, if you gained weight, the thyroid could come back into normal issue. Maybe they are afraid to mention weight issues? I don’t know. But your post is great in explaining the blood work needed to determine if you have a thyroid issue, which does not run in my family, to regarding it as a symptom of or ramification of malnutrition, etc.
so glad it was helpful! keep advocating for yourself <3
I love allll your posts!!! My thyroid levels are totally wacky, and I was curious about when you mention “there are many lifestyle changes that can help tremendously in healing low thyroid levels”. Could you give specific examples of these..?
I would love to but it’s something that we work with Nutshell clients on all the time so I want to be fair to them…thanks for understanding! 🙂
Oh yes, of course! Sorry! Love all your posts – you do such fab work 🙂
Geeeeesh I love your posts and you are super inspirational (and reassuring) when it comes to my decision to leave the ICU and go into primary care! I feel the same exact way. And I’ve heard providers speak to ordering what they consider unnecessary labs or whatever it may be, but imagine being able to save someone from taking all that medicine?! It’s crazy to me, actually! Thanks for another great post, Robyn!
I love your posts and am just commenting to get a different perspective on it but I was born with hypothyroidism because my dad was in Vietnam and exposed to certain things. The government is actually involved and I will be getting a settlement sometime in my lifetime. If I was not tested when born when they found this out I would have been mentally retarded. So while what your saying is all awesome it’s not possible for me to ever live with levothyroxine and 2 pregnancies made it even more difficult. I do 100% believe most foods can heal and keep me healthy, but with my meds not as a substitute.
Hi Leah,
I’m so sorry to hear this – my heart feels for you! Keep in mind that the whole point of this post is the relationship between restrictive eating/dieting and thyroid function – not a cause like you experienced so know that like I said above, medications do serve a purpose sometimes.
**without levothyroxine, I meant. OOOppps:)
Hi Robyn,
I’ve been a long time reader but have never commented until now (shy!). I honestly cannot say how much this blog has helped me in my recovery from anorexia. I know you said that the thyroid can heal after a period of undernourishment. However, I was wondering if there is still hope for my thyroid and hormones after SO many years of damage and undernourishment. I have had anorexia since age 12 (now age 25) and have never gotten my period naturally (I take birth control pills for my bone density and that has caused a “fake period”). I’m worried that there have just been too many years of damage.
Hi Gemma,
Thanks for commenting 🙂 You are not “too far gone” as I know many women feel – but you aren’t so stay hopeful! <3
Thank you so much for this insightful information, Robyn! I definitely notice that I have digestive issues when I start a new semester/job, and I know that it is because of the mental/emotional stress involved. It’s interesting to read about why that happens, so thank you!
great post, Robyn! I’ve been loving your blog lately and you break down information like this into such an interesting and informative format. Hormones and how they relate to dieting/restrictive eating/EDs has been fascinating me lately and the more I learn, the better I can counsel my own patients. Thanks for the inspiration!
Thanks for the informative article! I’ve been on synthroid for a long time because no doctors discovered my disordered eating. (That came from you! Thank you!) Now I’m on thyroid meds and wondering if I’ll ever be able to wean myself off?
hi,
I’m in the very very early stages of recovery from anorexia (i’ve been eating a “normal” amount of calories for about a week now after months of starvation) and i just had some bloodwork done that shows very low levels of T3 but normal levels of t4…i’m just wondering if i’ve actually developed hypothyroidism and if gaining weight back will now be “too easy” (i know this is still my disordered brain speaking, lol). i have all the typical symptoms of fatigue, hair falling out, cold all the time, depression and i’m wondering if medication or simply continuing to eat “normally” over the next few months will correct all this? i’m currently in the phase of having gained a bunch of water weight, but am i likely to gain real weight rapidly at first due to the low t3 and then stabilize? sorry if this post is a bit scattered!
Hi Harley! It’s hard to answer that without knowing your full history, but I would encourage you to pursue recovery over medication (but I would highly recommend talking this through with your doctor) I would also say that rapid weight gain would be a drastic way to think about it and that is your ED persuading you to continue in ed behaviors …don’t let it 🙂
The part where you talked about thyroid hormones levels is very true. In my experience, it seems that doctors will typically try to treat the hormone levels and get them into what they consider acceptable ranges. For some people, this is what they need, and getting their hormones into these levels will make them feel better. Of course, as you mentioned, this does not ring true for everyone. Some will still feel sluggish and tired, even though their thyroid tests show their T3 and T4 levels in ‘acceptable’ ranges.
Hi Robyn!
I was diagnosed with hypothyroidism in July of 2017, the same that I was diagnosed with mononucleosis as well. At the time I was diagnosed, I was probably about a year into what I would consider bulimia, and over the next few months I fought with my body to recover from the eating disorder as well as mono. I’m on a very low dose of synthroid, but as you have said and per other research I’ve done, it seems that eating disorders can cause these symptoms and potentially elevated TSH. I feel as though I need a new doctor because they never wanted to listen, they just wanted to throw medication at me. My question is, if I’m on synthroid (50mcg) can my thyroid still recover on it’s own and eventually my levels will become too low and I’ll need to be taken off the synthroid? Or is the influx of synthetic hormone disabling my thyroid from recovering full function on its own and maybe I should find a new doctor who is willing to give their input on this? It would definitely be nice not to have to take a pill every morning for the rest of my life! (I’m 21)
Thank you
Hello Robyn,
This article is awesome!! Thank you! Anyway I just had a question. Last June and July I didnt get my period but August I did. Then for 7 months I didnt get my period again. I know this was because I was on a strict diet of low carb and less calories in general. I excercized 5x a week as well. I was constantly freezing, constipated and had a low heart rate (48). Finally I stopped restricting and started eating more carbs. I got my period back the last three months! But I also gained 20lbs in three months. I am never cold anymore, my heart rate is normal (60) and I am not constipated anymore! However, I got my blood tested and my TSH came back a 6.10 (reference range 0.37-5.04). I am so confused though because I don’t have any symptoms of hypothyroid anymore!? Could it be my body just slowly getting back to normal?
Thanks so much!!
Hi Robyn! Just wondering if maybe you could make a post about how to repair a damaged thyroid from restrictive eating. Or maybe you have a few steps to take to start to reverse the damage and begin the journey towards healing? I am cold all the time, hair falls out, have slow and poor digestion and bruise very easily.
hi Robyn! I have been trying to recover from HA these last 5 months but was sad to see that my TSH has increased to 4.7. Any idea why this could be happening if I have stopped exercising, am eating more, and trying to reduce stress? I still have gut issues (SIBO) so am wondering if this could be related? I am feeling discouraged that my thyroid now seems to be in more of a state of panic and thus slowing down (higher TSH) even though I am trying to recover. Thank you!
Hi Robyn! Always love your stuff. This post is just perfect for me right now.
I had anorexia for about 7-8 years and my Dr found subclinical hypothyroidism about 1 year recovered. (Mind you, I was still undereating.) we waited a year to medicate & I am on Armour and have been the last 1.5 years.
I don’t feel better on it & do think the elevated TSH was from undernourishment.’is there hope to get off meds some day if I continue to nourish my body? Thanks!
So I think I have had an eating disorder but not diagnosed. Went 500 days without a period and started having weird things with my body. Dizziness, tremors, rapid heartbeat just to say a few. After several dr that said nothing was wrong I finally found one and he said hypothyroidism. I seem to go through cycles and feel great for a few months, I start working out more and I think I start eating less again. I just can’t break the cycle. I will keep eating more and not crazy exercising. Thank you for sharing