In the 1920’s, researchers at the Mayo Clinic used a ketogenic diet to treat adults with ideopathic epilepsy. In 1930, Dr. Clifford Barborka published a paper detailing their findings with their first 100 patients. Among other findings, Barborka notes that 20% of the women involved in the study experienced complete cessation of menstruation during treatment, which didn’t return until a normal diet was resumed. He only reported on menstrual cessation, but given more contemporary research on the subject we can reasonably speculate that many more women experienced menstrual irregularities that stopped short of complete cessation. Subjects were eating appropriate calories to maintain their weight, so weight loss was not a confounder here. He speculates that it may have been related to a vitamin B or E deficiency, but has no clear explanation. (Note that this was many decades before the discovery of Leptin and it’s role in hormonal regulation.)
In 2003, researchers published their retrospective study of 45 adolescents aged 12-19 treated for epilpsy with a ketogenic diet over 8 years. They noted that 45% of the girls involved in the study reported menstrual irregularities, most (2/3) of whom experienced complete cessation of menstruation (the other 1/3 were reported as experiencing delayed puberty or menstrual irregularity). Most resumed menstruation after ending the diet. 2 were treated with hormone therapy to induce and regulate menstruation. A majority of the girls did not lose weight on the diet, so again, weight loss was not a confounder in most cases. Researchers speculated that:
“The diet may mimic the menstrual side effects seen in starvation and certain female athletes.”
In 1999, a group of researchers published a review of a small group (9 women, 2 men) of otherwise healthy adults treated for epilepsy with a ketogenic diet. Of the 9 women involved in the study, 100% experienced menstrual irregularities. Although five of the 11 study subjects initially reported weight loss on the diet, calories were increased to manage it, so again, weight loss was not a confounder in most of the cases. From the researchers:
“All female patients reported menstrual irregularities. This is not uncommon, considering that menstrual irregularities are reported in other high-ketone states such as starvation.”
My friend Batty’s menstrual chart before (left) and after (right) experimenting with dietary restriction. Click on image to read her story.
As researchers noted, there’s some reason to speculate that the human body responds to carbohydrate restriction similarly to the way it responds to starvation. Certainly science has shown that leptin levels are sensitive to both calorie restriction (1) and carbohydrate restriction (2, 3, 4) and that women experience a greater leptin decline than men in response to dietary restriction and weight loss (5, 6). More and more research is indicating that leptin is an important endocrine mediator, acting on pituitary, adrenal, thyroid and gonadal axes, as well as playing a role in bone formation (7, 8). Another well-documented side effect of both ketogenic diets and starvation is bone demineralization (9, 10, 11, 12). Starvation and carbohydrate restriction can also both produce thyroid downregulation (13, and read Anthony Colpo’s exploration of carbohydrate restriction’s influence on thyroid function here).
I’ve worked with many women dealing with thyroid and reproductive dysfunction who also have a history of dietary restriction in the pursuit of an aesthetic ideal. My experience, coupled with the science I’ve seen, leads me to take a very cautious approach to dietary restriction in all it’s forms, with emphasis on promoting consumption of as rich a variety of calories and macronutrients as possible while allowing for the maintenance of a healthy weight. I think our culture has taken a myopic view of health, fixating on weight and fat loss, while tending to overlook other important markers of health. Most of the contemporary studies on extreme calorie and macronutrient restriction are short term, focused on only a few metabolic parameters (insulin and glucose dynamics and weight loss, most often) and/or focused on men, and I’ve found very little attention paid to leptin dynamics, thyroid health and menstrual function in the literature. The best use for highly restrictive diets are in the treatment of the illnesses they were developed to treat, and under the supervision of a qualified medical professional. For generally healthy people, a more modest, if slower, approach is probably the most prudent.
What do you do, though, if you’re already experiencing symptoms of endocrine adaptation to starvation? First of all, you may have an eating disorder, and even if you don’t you will still likely deal with issues associated with eating disorder recovery as you work your way through this stuff. Finding a medical professional with ED experience would probably be very beneficial, if for no other reason than that they can give you an idea of what to expect as your body recovers. Ask your doctor for a referral to an endocrinologist if possible. Eat! You should be eating at least as many calories as your body burns each day. If you have a history of undereating, you may need to keep track of your calorie intake to ensure it is adequate to support your energy needs. Carbs are helpful in raising leptin levels, so don’t restrict them unless you have a medical reason to and are being monitored by a medical professional. Prioritize sleep. Ask for help. You are not alone.
Thank you for this! Very interesting, especially given how little attention is often paid to physiological differences when giving blanket nutrition advice on the interwebs.
Do you think carb backloading could have similar effects on the menstrual cycle? Still eating plenty of food, and plenty carbs overall, just not during certain parts of the day? Obviously research hasn’t been done on this, and somehow I doubt our bodies are THAT lacking in resilience, but at this point I’m grasping at straws. Haven’t menstruated since I went off BCP in October. I’ve gone back to eating carbs whenever I want, but am wondering if that could have had an effect. My doctor sent me information recommending upping intake, and its recommendations were literally half of what I eat daily. So I don’t think undereating is the issue here.
Were you on a restrictive diet before? I think you might do well to see an endocrinologist. 9 months is a long time to have gone without a period.
Not for any extended period of time. Just very occasionally/temporarily to make my weight class, and even that wasn’t very restrictive. My gyn ran some thyroid tests and it came back normal, though I don’t know specifically what tests those were. I’ll talk to him about it more, but an endocrinologist is a good idea. Thanks!
Is it possible your body fat is simply too low to support reproductive function?
Perhaps? I don’t think it is absurdly low, but I’m sure different people lose reproductive function at different points. I haven’t had it measured because doing so accurately is expensive, but my weight at least is smack dab in the middle of the healthy range on BMI charts. I know those don’t necessarily indicate health, just stating that I’m not underweight.
Hey there Strongerer! I can attest that body fat percentage and menstruation are very individual – my cycle gets erratic if I drop below 18% bodyfat, which to me doesn’t seem very low, but it is to my body. Also, carb backloading was very bad for me – if you’re talking about the kind where you’re very-low-carb at all times except for the 4-6 hours just after resistance training. Don’t be fooled, unless you are an anaconda and can fit 5000 calories of carbs in your mouth in one sitting, it is still a low-carb diet! I had a honeymoon phase with it of about a month, and then everything started sliding – weight loss, exercise performance, everything. Carb backloading is, after all, pretty much just a ketogenic diet with some timed workout-recovery nutrition thrown in, and there is almost no science backing it up as far as I found. However, that’s not the same thing as eating normally and just eating more carbs the night before a really hard training session (which is awesome!)
Thanks for this! It’s like you are writing this for me! Was on a low cal/low carb diet while doing intermittent fasting and riduculous amounts of exercise. Then the periods started going from 28 days like clockwork to 6-8 weeks! Now back on track with the cycle but have weight gain (12lbs) and my BMR tested in a lab was just over 1000 cals (37yo, F, 150 lbs). Who should I be seeing to help me? Dietician, Endo? I just want to ‘Eat the Food’!!!
I will be honest here, I think you should be working with an ED treatment team. Even if you don’t have a diagnosable ED, you are dealing with all the symptoms, and an ED professional will be able to guide you through recovery in the healthiest way.
I know you’re right. I just didn’t want to go there! appointment is made. Thank you for all that you do!
I just wanted to tell you that you saved my life! Well, in sorts! haha I started a restrictive diet last July. I was working with a “health coach” and I loved the aspect of the diet in theory, because it seemed healthy to me. It actually did teach me to eat better and make better choices. At first it went really well! I started at 240 and got down to 190 in 4 months. I felt great, and my cycle was actually more regular! (I had symptoms of PCOS before.) My coach then started to restrict my carbs. Obviously to cut more fat faster. After a few months, and hardly ANY weight loss, and a slew of other symptoms, I found you through facebook. I started reading your info, and couldn’t stop. Then I came upon the realization, that I was starving! My hair was falling out, I was freezing (hands and feet), my brain was extra foggy, I was super grumpy, and my sex drive fell off the face of the earth. All the things you talked about that you experienced when you dropped your carbs lower. I IMMEDIATELY stopped what I was doing. I put my carbs back in my diet, which was mainly fruits, and ever since then, my life is back! And, I HAVEN’T GAINED BACK ANY WEIGHT! I haven’t lost any more, and I’m totally okay with it, because I know that I will if I just keep working hard. It was just amazing to me, that what I thought was so healthy (1200 calories a day), was slowly killing my brain and reason to function. So, THANK YOU! Thank you for what you do, and for your voice! I admire you, I think you’re simply amazing, and you changed my whole outlook on life! XOXO
Thank you SOOOO much for this post!! Something that FINALLY makes sense! I lost a fair amount of weight over a year ago and subsequently have lost my period for about a year and half now. My calorie intake is fairly low and level of physical activity is fairly significant with absolutely no weight loss – in fact I have gained about 7 pounds since reaching my lowest point. My body fat is in the “normal” range and I have been extremely frustrated with the lack of menstruation and lack of weight loss despite all of my efforts.
This article is a huge eye opener and sounds exactly like what I’m experiencing (my carb intake pretty much only consists of those found in fruits and vegetables). Thank you so much again for posting this!
I just feel like I can’t win here. I am borderline type 2 diabetic. I went on a very low carb diet. I dropped my A1C to 5.3 and fasting insulin to 4 in 3 mo with the diet change. I got pregnant right after that and stayed low carb throughout the pregnancy. It’s the best I’ve ever felt. Then after reading so many articles scaring me about being too low carb I allowed myself to increase carbs.
My A1C went up. My fasting insulin went up. And my testosterone went up. And eating higher carbs I feel like crap and crave more carbs. I have had 3 miscarriages in the last year. I’ve since found two studies showing that all women in the studies miscarried when their percentage of free testosterone levels are as high as mine, the cut off point for miscarrying is actually lower than mine.
But to lower my testosterone, to lower my miscarriage risk, I need to lower my insulin, which requires lowering my carbs. But I’m told it will totally screw me up including my cycles. I feel like I just can’t win here. *sigh* And, yes, I’m also hypothyroid but I got hypothyroid on a high carb diet now a low carb one.
Wow, you’re dealing with a lot, and I hope you’re working with an endocrinologist and registered dietician to address these issues! Your needs are well above my pay grade. '? There are things in addition to diet you can use to address insulin resistance (exercise and adequate sleep, for instance), and an experienced medical professional can help you fine tune your treatment options.
Hi, thanks for this, it’s interesting, but do you have any idea how long periods usually take to return? I had an eating disorder for a few years probably, but my periods stopped when I was still at a reasonably healthy weight and have never returned (probably 4 years or so). I don’t really mind not having them, to be totally honest and the doctor doesn’t seem too concerned, but it seems odd as I’ve been eating around 2000 calories a day for the last year or so and am eating a reasonably healthy balance incl carbs etc.
thanks also, your articles are always really interesting.
Thanks for this – it was very interesting reading.
I have a question in relation to this though… does being on the contraceptive pill maintain the menstrual cycle even though calories are restricted (1500-200cal) and exercise is high (800-1200cal/day)? Or would menstruation cease even while on the pill?
Menstruation *always* ceases when on the pill – even if you have a monthly bleed, it’s not true menstruation, because “menstruation” is actually a whole hormonal cycle that involves ovulation, among other things. In a natural menstrual cycle (to dumb things down a LOT) your body gets all ready to get pregnant by producing hormones that stimulate an egg to be released (ovulation) and then, when the egg isn’t fertilised, all those hormones wind down and when they get to their lowest point, you menstruate (have a period.) The pill prevents you from ovulating, full stop. No ovulation, no period. It’s possible to have non-ovulatory periods when not on the pill too. But no, the pill does not protect against the endocrine adaptations to starvation or ketosis.
It’s really great to have someone on the net really focusing on the science as it relates to women. It’s tough because there simply isn’t as much research on us as there are on the guys, but we are definitely not the same! '?
Great write up!! Even more awesome is that you know Batty!! She rocks my socks too!!
Ok – this post was cool! This past early spring I was experiencing menstrual spotting/skipping weirdness and had no idea why. I’m at a good weight, I EAT – oh man do I EAT… ‘cept I was not eating many carbs. I wasn’t “trying” to keep them out on purpose I wasn’t afraid of them, but somehow it just sort of happened.
Partly, the gym I go to told me my plate should be meats and veggies and not many carbs. I guess I skewed things a bit that direction.
I was reading some things around the time, decided to add in more carbs and experiment… and I’ve had a normal period since. My weight didn’t go up, I didn’t experience any “negative” side effects or anything.
Goes to show that anyone, even well intentioned – and in a place of – well not authority really – but at a gym I just figured he would know…. but yeah, people DON’T know what they don’t know all the time.
Gotta keep experimenting with your own bad self and see what works for you! '? Great article! We are the N1….
Well, shit, that’s me. I’d been wondering what’s happening with my body for the past two years' ironically I haven’t even been consciously trying to undereat or lose weight, just get my IBS under control and (you’ll love this) eat a more healthful diet. Har har har. I’m still “mostly healthy”, just having some mild issues with my menstrual cycle and with feeling sluggish, and it’s only as I added running to my workout regime (I lift three days a week and run two or three days) that I thought it’d be worthwhile to check my macros and calories to see that I’m eating enough to sustain all this exercise. I’m' really not.
We’ll be cycling to the bakery for bread tomorrow morning and chasing that down with ice cream. '?
This is so right on! I lost my period pretty much for 3 years while following a paleo lifestyle that became low carb because I didn’t loose any weight just eating paleo (I didn’t even have any to loose!). Going low carb did let me loose those 5-10 lbs that I was always bothered by but it also never got my period back. I thought I just needed to eat cleaner and never, ever thought my loss of period had to do with my diet as I was at a normal weight. I tried everything including acupuncture, Chinese herbs, essential oils, vitamins, massage, meditation, black out blinds, therapy, very clean eating (no grains or sugar- raw dairy, liver, fermented foods, etc) and nothing worked.
Then I tried progesterone as a last resort (I was trying to do everything natural) but it didn’t work as my estradiol was in the post-menopausal range and I’m not in pre-menopause! Long story short I realized that it was because I was under eating. I started eating 2500-3500 calories daily and stopped exercising and my period came back less than 3 weeks later. Now I’ve had it twice and I anticipate a third time soon (or maybe I’ll be pregnant, which is my ultimate goal). I eat loads of carbs! By the way, I saw an endocrinologist, neurologist, pituitary brain specialist, OBGYN, etc all before to make sure there was no other reason I wasn’t getting my period. It was seriously just my low carb/low calorie diet. I never, ever would have thought that before because I looked healthy and every doctor said my diet was amazingly “healthy”. Thanks for all you do, Amber!
Thank you for sharing Lily! The more stories like yours that are told, the faster we will turn this ship around. Keep sharing!
This conversation is fascinating to me. I had a lot of trouble getting pregnant with my first child – I charted and did everything “right,” but after 11 cycles, I wasn’t pregnant. My periods were very regular, but I did notice that I had a borderline short luteal phase. I was eating a low carb, low fat diet (ala South Beach) because I thought that was healthy. My BMI was low-normal, and I exercised only occasionally. I did have another problem – my hair, which has always been thin, was falling out alarmingly. Finally, in desperation, I read a book about getting pregnant and there was one paragraph devoted to being body fat. I checked my body fat with a formula and discovered that it was too low – only in the 16-17% range. It was such a shock to me that my diet–which I thought was going to help me–was actually hindering me. I immediately carb loaded and gained five pounds in a month and got pregnant that next cycle. Now I realize that this was probably hormonal more than anything. Since then, I have stayed away from low-carb diets and have focused on real foods. This post and others have helped me realize how dangerous it can be to play too much with what you eat. What amazes me now is that I went to the doctor to figure out why I couldn’t get pregnant, why my hair was falling out and no one suspected my diet.
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