Meet Mark

Let me introduce myself. My name is Mark Sisson. I’m 63 years young. I live and work in Malibu, California. In a past life I was a professional marathoner and triathlete. Now my life goal is to help 100 million people get healthy. I started this blog in 2006 to empower people to take full responsibility for their own health and enjoyment of life by investigating, discussing, and critically rethinking everything we’ve assumed to be true about health and wellness...

Tell Me More
Stay Connected
June 19, 2012

Dear Mark: Women and Intermittent Fasting

By Mark Sisson
415 Comments

Many differences exist between the two sexes. We look different. We sound different. We dress differently from each other. We like different things. Different genres of movies cause men and women to cry (differently). And although society, media, and culture drive and/or inform many of our differences, some are inherent and physiologically-driven. For example, men and women have different biological equipment – both external and invisible to the naked eye – that change how we interact with and respond to our environments, our exercise, our sleep, and our eating habits. Nowhere are these gender differences more evident than in the realm of health and nutrition, and yet it seems that I’ve overlooked a big one: different sex responses to intermittent fasting.

Let’s take a look at a couple recent reader emails:

Hi Mark,

I’m a woman (28 years old) who followed your recent fasting series with great interest, gave it a shot, but had mixed results. Then I read this post, which mentioned your series and questioned the suitability of intermittent fasting for women. Is it true? Do we respond differently than men? What do you think of that post? Thanks!

Claire

Dear Mark,

Paleo for Women blog says that fasting may not be for women: that it’s more suited for male physiology. I have been fasting for three years and never experienced any missed periods/sleeplessness, etc. Moreover I got a handle on my mindless eating. Can you give your word on IF for women?

Varsha Tiwary

Thanks for writing in with your questions.

First of all, I really, really liked Stefani’s post. I should say “posts,” actually, since Stefani Ruper (who wrote the post linked in the reader question) also just did a guest post on Free the Animal, in which she discussed the treatment of women’s issues in the community at large. While I don’t agree with everything she said, both were quite well done.

Even though her articles – for lack of a better phrase – “called me out” (in a completely non-confrontational way), I was actually quite happy to read them. Heck, I was happy to read them because of it. After all, I’ve always encourage people to be critical about what they think they know about nutrition and fitness, and to be skeptical about what they read on the Internet – my articles included. The beauty of MDA is that it isn’t one-sided. I get constant feedback from readers that send me down new paths of inquiry, and it’s through this kind of crowd-sourced effort that the Primal Blueprint message grows and becomes stronger than it already is.

I also appreciated Stefani’s articles because they do highlight a blindspot – not just in my own series of posts, but in nutritional science as a whole. In the push to eliminate the confounder known as inherent endocrine gender differences, they’ve forgotten that real life is a series of confounding variables all pushing, pulling, poking, and prodding at the results we get. They’ve forgotten that while their results may represent fodder for publishing and accolade accumulation and hypothesis confirmation (or rejection), real live humans in normal living situations are not placebo-controlled. That women are not the same as men and respond differently to stimuli and stressors isn’t a “confounder”; it’s a fact deserving of further study! Because what are we ultimately trying to do here – put together nice, neat, peer-review-ready trials, or help real people living real lives?

Since I’m trying to do the latter, I happily accept constructive criticism. So should we all.

So, what did Stefani’s research find?

Fasting has different endocrine effects on male and female rats.

In male rats:

No matter the duration or degree of nutritional stress, male rat brain chemistry responds with similar changes. Nocturnal activity and cognition stay fairly stable, regardless of the intensity of the fast. If you push the fast long enough, males will get a little wonky and frantic, but overall they maintain pretty well. It’s like they’re equipped with the ability to handle nutritional stressors.

In female rats:

Any degree of nutritional stress (fasting or mere caloric restriction) causes increased wakefulness (during the day, when they normally sleep), better cognition (for finding food), hyper alertness, and more energy. In short, female rats become better at finding and acquiring food when they fast, as if their bodies aren’t as well-equipped to deal with the stress of going without food. They also become less fertile, while the males actually become hornier and more fertile (probably to account for the females’ plummeting fertility). Ovary size drops (bad for fertility), adrenal gland size increases (which in rats indicates exposure to chronic stress), and menstrual cycles begin to dysregulate in proportion to the degree of caloric restriction.

In humans, the male-female fasting literature is quite scant, but Stefani also found considerable differences beween the sexes, when data was available:

  • One study, which I’ve cited before as evidence of a benefit to fasting, found that while IF improved insulin sensitivity in male subjects, female subjects saw no such improvement. In fact, the glucose tolerance of fasting women actually worsened. Ouch.
  • Another study examined the effect of alternate day fasting on blood lipids. Women’s HDL improved and their triglycerides remained stable; men’s HDL remained stable and their triglycerides decreased. Favorable, albeit sex-specific results.
  • Later, both obese men and women dropped body fat, body weight, blood pressure, total cholesterol, LDL cholesterol, and triglyercides on a fasting regimen. These people were obese, however, and perimenopausal women were excluded from the study, so the results may not apply to leaner people or women of reproductive age.

I figured I’d look through my other recent fasting posts for data on female (preferably pre-menopausal) responses to fasting. Here’s what I found:

  • In the only heretofore extant human study on fasting and chemotherapy, seven females (including a 44-year old woman who was likely premenopausal, given when menopause usually onsets, though it wasn’t explicitly stated) and three males found that IF improved their tolerance to and recovery from chemotherapy. Takeaway: male and female (mostly middle aged, though that’s the population that generally gets cancer and undergoes chemotherapy) chemotherapy patients appear to benefit equally from IF.
  • Although both men and women displayed greater increases in VO2 max and resting muscle glycogen concentration in response to fasted cycling training, only men showed greater skeletal muscle adaptations when fasted. Women had better muscle adaptations when fed. Takeaway: fasted endurance training, then, may work better for women than fasted weight training.

As it stands right now, I’d be inclined to agree that pre-menopausal (and perhaps peri-menopausal) women are more likely to have poor – or at least different – experiences with intermittent fasting, at least as a weight loss tool. That said, it appears to be a potentially gender-neutral therapeutic tool for chemotherapy, cancer, and age-related neurodegeneration patients.

As I alluded to earlier, this is what I love about this open forum we call the Internet: the fact that if you leave something out, or overlook a key point, someone will call you out on it, most likely publicly. When that happens, you grow despite yourself. If not for Stefani’s posts, I may never have taken a closer look at the inherent differences in men’s and women’s metabolic responses to fasting. I certainly receive enough feedback from female readers for whom fasting has been helpful, so it’s good to see another side.

To sum things up – if such a thing can even be done – and answer the questions in the intro, men and women have inherent metabolic and hormonal differences, and it’s evident that these differences in part determine how we respond to a stressor like intermittent fasting. I’ve never prescribed intermittent fasting as a requisite piece of the Primal lifestyle, but rather as an adornment, a choice, a potentially therapeutic strategy that each individual must test for him or herself. Although my recent series on fasting might have thrown some people off, I want to reiterate that I am not a huge IF guy. For myself, I generally fast when it makes sense – if I’m traveling and good food isn’t available, if I’m just not hungry, stuff like that. I periodically do 16/8 or 14/10 (i.e. eating in an 8 or 10 hour window) and find it works great for me because I am fully fat-adapted. But even I don’t hold rigidly to that. It’s not for everyone. And that hasn’t changed.

So who should and shouldn’t consider fasting? Have my recommendations changed?

If you haven’t satisfied the usual IF “pre-reqs,” like being fat-adapted, getting good and sufficient sleep, minimizing or mitigating stress, and exercising well (not too much and not too little), you should not fast. The pre-reqs are absolutely crucial and non-negotiable, in my opinion, especially the fat-adaptation. In fact, I suspect that if an IF study was performed on sugar-burning women versus fat-adapted women, you’d see that the fat-burning beasts would perform better and suffer fewer (if any) maladaptations.

I would also caution against the already lean, already calorie-restricted woman jumping headfirst into IF. I mean, fasting is ultimately sending a message of scarcity to your body. That’s a powerful message that can get a powerful response from our bodies. If you’re already lean (which, depending on the degree of leanness, arguably sends a message of scarcity) and restricting calories (which definitely sends a message of scarcity), the response to fasting can be a little too powerful.

I’d also say that daily fasts, a la 16/8 or even 14/10, run the risk of becoming chronic stressors and should be approached with caution by women. Same goes for ultra-long fasts, like a 36 (or even 24) hour marathon. Most of all, though, I’d simply suggest that women interested in fasting be cautious, be self-aware, and only do so if it comes naturally. It shouldn’t be a struggle (for anyone, really). It shouldn’t stop your cycle or make it harder for you to get pregnant. It should improve your life, not make it worse. If you find that fasting has those negative effects, stop doing it. It should happen WHEN (When Hunger Ensues Naturally), if it happens at all.

I’m not going to say that women should or shouldn’t fast. I’ll just echo Stefani’s advice “to look at options, to be honest about priorities, and to listen to one’s body with awareness and love.” Frankly, everyone should be doing that, but with regards to fasting, it looks like women should probably hew a little closer to her words.

Of course, if I had to make one minor quibble with the content of Stefani’s otherwise outstanding posts, it would be her source for the number of unique visitors Mark’s Daily Apple gets each month. Nowadays, we’re actually getting closer to 1.5 million monthly uniques, not 250-300,000… but who’s counting?

That’s it for me, today. What about you? If you’re a woman who has tried fasting, or know someone who fits the description, let us all know about your experiences. I’m intensely curious to hear from as many of you as I can. Thanks for reading.

Subscribe to the Newsletter

If you'd like to add an avatar to all of your comments click here!

Leave a Reply

415 Comments on "Dear Mark: Women and Intermittent Fasting"

avatar

Sort by:   newest | oldest | most voted
Paleo Bon Rurgundy
4 years 5 months ago

FYI: Robb Wolf’s Paleo Solution podcast episode 136 discusses estrogen and paleo.

KM
KM
4 years 5 months ago

I fast regularly and have found no such problems. I generally do between 20-36 hour fasts a couple of times a week. I do fasted training also and find that by the end of the fast I feel rejuvenated not faint. I prefer how I feel in a fasted state than when I have eaten throughout the day. I feel it resets my body and its nice to take a break from eating.

Jodis
Jodis
4 years 5 months ago

Er, that’s all well and good that all that works for you, whoever you are. But without the sex, age, and (if female) stage (pre-, peri-, or post-menopausal), it doesn’t tell me anything. What was your point?

Paleo Bon Rurgundy
4 years 5 months ago

Meow!

Tracy
Tracy
4 years 5 months ago

Inappropriate and sexist

rabbit_trail
rabbit_trail
4 years 5 months ago

lol

Andrea
Andrea
4 years 5 months ago

I love Ron!

Lauren
Lauren
3 years 9 months ago

A woman disagreeing with someone does not warrant a “meow”, you are actively part of the problem.

Primal Toad
Primal Toad
4 years 5 months ago

Her point is that fasting is working for her brilliantly and thus may work for someone else. She is sharing her experience like everyone else…

Jodis
Jodis
4 years 5 months ago

How do you know KM is she and not he? There is nothing in the post to indicate gender, thus my questions.

I’m not trying to be catty (Rurgundy not withstanding), I’m trying to elicit information that I believe MIGHT illuminate whatever KM’s post was meant to illustrate. I’m trying to get him/her to SHARE MORE of his/her experience. Sheesh!

Primal Toad
4 years 5 months ago

Jodis – I am not certain but this post was directed at women so that is why I am assuming it is a women. I could be wrong…

ML
ML
4 years 5 months ago
Actually, what KM wrote is the same for me. I am 52, post-menopausal. I am actually tired of most articles and bloggers like this Stefanie person stating that her findings are for ALL women when they are not. NOTHING is right for everyone. Everyone is different and what works for some don’t work for others – that includes IF, Paleo/Primal, low carb, etc. I think her POINT was that this woman and other writers should say this or that may or may not work for a people or a certain group. That IF article is like a blanket statement that… Read more »
Rachel
Rachel
4 years 5 months ago
I actually agree with you but would like to point out that Martin over at Leangains has strongly instigated all of our physiology is alike, and that women can routinely IF too. As a woman who has tried his protocol on two separated occasions for 6+ weeks each time and has GAINED weight in the form of fat both times, despite tracking calories and other data, I am thrilled to see this post. I suspected my body was interpreting the fasting as a chronic stressor because it was making me want to binge eat, which is not something I get… Read more »
Lena
Lena
4 years 5 months ago
I’ve had the same experience as the commenter who talks about gaining on the leangains protocol. After being stable at my weight for about 8 months, I started GAINING weight when I started IFing. Also, I experienced the opposite of people who say they got a handle on their binge eating. After a fast of anything over 16 hours, I eat like a starving lion. I can’t control myself. I don’t have this problem if I eat 2 or 3 meals everyday. The binging happens even if I’ve eaten a lot before the fast, so it’s not like I’m making… Read more »
Chloe
Chloe
4 years 5 months ago

“Everyone is different and what works for some don’t work for others – that includes IF, Paleo/Primal, low carb, etc.”

I totally agree with you ! Sometimes I’ve got the impression we are creating new religions with low-carb, veganism & lots of statements about health and what is correct for us (“because the last studies showed that…”)

We got too much information & don’t listen to our body enough.

I’m a 25 years old female & I feel great with IF. Sometimes with no breakfast, sometimes longer than 24 hours. Sometimes with fresh juices.
With no rules, just the feeling.

Oceanside Grokette
Oceanside Grokette
4 years 5 months ago
Agreed with this, there is no such animal as ALL women, we’re all individuals with various levels of similarity and difference. I think THE most useful take-away knowledge on nutrition is that there is just as you say- there is nothing that works for everyone. There’s no universal one-size-fits all. Also, IF works fine for me. I do daily fasts of 12hrs from waking up, then a 4hr meal window to drink wine and enjoy cooking and grazing as I choose, then fast the remaining 1-2hrs before I go to bed. This also allows me to just not bother with… Read more »
Elenor
Elenor
4 years 5 months ago
On the other hand (oh, I’m an overweight, post-meno., woman), Stephani’s entry was an amazing head-slapper for me! I’ve been adjusting my life, enjoying more than I can say being, if not a fat-burning beast yet, at least fat-adapted enough to enjoy NOT craving food at any particular time… I’ve been heading towards a more intentional IF. Instead of just waiting till I get hungry, I’ve been planning on doing longer / intentional fasts. (Right now, I often go from dinner till noon or 1 or 2 without really noticing (well, except my morning coffee) — so I’m doing some… Read more »
Michelle
4 years 5 months ago
I so agree with you! I am a 41-year chef and yoga teacher who also happens to be a pro fitness model, (I compete with several drug-free federations and you can find me in magazines like Oxygen and Inside Fitness). As a body-builder, experimenting with diet and training ad nauseum and whittling down to 8% bodyfat is what we have to do to win, and for me, (and quite a few of the other women on our team) cycling in really low-calorie, (700 kc) and no-carb days has resulted in great gains for us. Speaking only for myself, when I… Read more »
Amy
Amy
2 years 6 months ago
I am a 43 year old woman who most of the time ate a ketogenic diet. Over the years I had slipped and gained weight from a lean size of 2 to a 4 with love handles! I thought I was doomed and it was hitting forty that ended my tone physique. However, that was not the case. It is all about food and making the right choice. I have been doing IF for two months and am back to size 2 (with no rigorous gym routine, just yoga and walking for cardio). I fit into jeans that are ten… Read more »
jh
jh
1 year 11 months ago
Just to add to the collection of testimonies for those interested: For my diet, I combine daily IF with high fat, grain free, leafy green predominant low carb and perhaps a few paleo principles (but NOTHING will keep me from my peanuts, peanut butter and purest love for fine aged and cottage cheeses) 28 yo F serious endurance athlete (80 mi/wk on foot + 130 mi/wk biking – I have been training this way for about 4 years) Practicing daily IF (ranging as low as 12/12 up to 20/4) since March 2014. Along with a grain free low carb, high… Read more »
Stacy
3 years 1 month ago

Er…could said it with a less snotty tone…..sheesh!

Stacy
3 years 1 month ago

And I was referring to Jodi’s comment to KM.

connie
connie
2 years 2 months ago

I hve tried IF and gained weight also.,.,im 48 yrs old and discouraged.,.,

Amy
Amy
1 year 8 months ago

Her point is anecdotal but about as good as this article’s sources as well. Each “study” he cited had at most 8 women or female rats…. That is the worst and laughable sample size amount I have ever heard of. thats like a 30 percent margin for error so your data basically has no authority

Groktimus Primal
4 years 5 months ago

If Mark ever figures out the difference between men and women I will accept religion and appoint him the one true God.

rob
rob
4 years 5 months ago

Re the difference between men and women: no man with half a brain is going to touch that one with a ten foot pole.

BillP
BillP
4 years 5 months ago

Isn’t ‘man with half a brain’ redundant?

signed,
Women everywhere

John
John
4 years 5 months ago

Funny! (though some seem to miss it…)

em
em
4 years 5 months ago

Naw, naw… It’s not that you men only have half a brain, it’s that you’re only *using* half a brain. Robust corpus callosum for the win! 😉

John
John
4 years 5 months ago

So that’s my problem – my corpus callosum isn’t working!

Wonder if I’m only using the left or the right…..

Hmmm…. perhaps if I get ready to jump off a roof… and my logical brain stops me… it’s the left I’m using, but if my artistic brain says Grok Swan Dive!… I must be using my right….

Hey guys… watch this!!

Paleo Bon Rurgundy
Paleo Bon Rurgundy
4 years 5 months ago

@Tracy: Is the comment ‘man with half a brain’ sexist and inappropriate too? Or good for the goose but not the gander?

Frederik
Frederik
4 years 5 months ago

sexist and inappropriate 😉 – remember sexism doesn’t mean (inappropriately) discriminating because of female sex, but any sex.

Roberta Saum
4 years 4 months ago

Not this woman. 🙂 I love all the smart men out there, and respect them tremendously along with the women.

AS
AS
10 months 1 day ago

Ouch!

Mimi
Mimi
5 months 8 days ago

OMG STOP that is so damn funny!

Michael
Michael
4 years 5 months ago

Or a 50 foot pole. There is differences between male and females but you can’t describe it I guess. You can say it but do you really get the point of it?

Michael
Michael
4 years 5 months ago

I meant “There are differences”

Julia
Julia
2 years 3 months ago

The differences between women and the differences between men are greater than the differences between women and men, so lets get over this already and just talk about our individual experiences as people experimenting on ourselves.

Brad
4 years 5 months ago
“Intermittent fasting…as a requisite piece of the Primal lifestyle, but rather as an adornment, a choice, a potentially therapeutic strategy that each individual must test for him or herself”. Well said! I think intermittent fasting works best when it is done randomly, as opposed to some set schedule. If i am not hungry for whatever reason, i will not eat. Simple as that. Do i fast intermittently weekly. No, not always. Sometimes i may fast a few times a week. Some weeks i may not fast at all. Some days i eat 1 meal, others 2, or even 5 or… Read more »
Nicole
Nicole
4 years 5 months ago

Amen!

Tom Bassett-Dilley
Tom Bassett-Dilley
4 years 5 months ago

Right on. Super hot here in Chicago right now, not going to sprint, and pretty low appetite…this is how it’s supposed to work, right?

Bec
Bec
4 years 5 months ago

Agree!
IF or the compressed eating window of 8 hours, has really helped me listen to my bodys hunger signals, and make those signals clearer too.
I love it! I eat when I am hungry, and I find that when I am fasting I am not as obsessed with food.

Luke M-Davies
4 years 5 months ago

Agreed – I have been using IF / EatStopEat patterns for the past couple of years. Not as regularly as I would like but I have sustained high levels of activity/calorie burning therefore need fuel for my body to use.

That said – I do prefer randomly using fasts. I think this is more effective at ‘shocking’ my body into fat loss but equally more therapeutic. If I knew I had to fast every Thursday, I think it may become a bit of a chore and more likely to be skipped!

Brad
4 years 5 months ago

“If I knew I had to fast every Thursday, I think it may become a bit of a chore and more likely to be skipped!”

Yes, that is precisely how i feel, too.

Roberta Saum
4 years 4 months ago

I would agree with this. This is exactly what I did when I fasted to lose weight. I didn’t force it. I would decide each day if I felt like doing it again, and throughout the day decide if it was right to keep on going or not. Always listening to the body. However I can’t do this anymore at or below 10% BF. The body now says no. I can do shorter fasts, not longer than say 17 hours.

Lindsay
2 years 5 months ago

It’s great to hear someone else refer to it as, “the body.”

vmckenna
vmckenna
4 years 5 months ago

When I wrestled in high school I would sometimes go almost two days without any substantial food, but could still function even with high intensity workouts. My mom, on the other hand, could not go twelve hours without food. She starts feeling sick, neseus, and gets headaches. Almost like she is going into shock.

Debra
4 years 5 months ago

12 to 14 hours is about my limit, too, and that is overnight. Although I am in my 50s, I have never been able to go long without food, until I began eating Primally. Now, at least I can go 4 to 6 hours between meals without the low blood sugar blues. I also find when I start sneaking carbs back into my diet, I wake up ravenous in the middle of the night. Low carbs equals steady blood sugar and easier fasting.

Stefani
4 years 5 months ago

Yes! Also, of course, in advocating stepping carefully around fasting, I am in no way advocating grazing. I still believe people, broadly speaking, should eat 2-4 meals per day, just reasonably spaced.

jacquie
jacquie
4 years 5 months ago

For the past 6 years, every day, i only eat between 7am to 2pm, the body takes time to adjust. I am a 47 yrs old female, not menopausal yet, and weighs just under 50kg. I guess this would not be IF as its daily? I find that not eating after 2pm allows me to wake up fresh and hungry. But i do not train paleo, but a yoga in the iyengar and ashtanga tradition for over10yrs.

Ma Flintstone
Ma Flintstone
4 years 5 months ago
Just found you Stefani, with this post’s link. Great to read. Wonderful. I’m a 39 yr old woman, still breast-feeding my three year old (not exclusively- he’s a primal boy). My husband fasts pretty much daily and has become a machine on the primal diet although he ..?can’t eat breakfast- never has as an adult. So he IF’s on weekday mornings till lunchtime and some weekends, activity depending. I MUST have a full breakfast; greens cooked in garlic, fat and broth with nori flakes and egg yolks and a cheeky roasted drumstick for example. My second meal is meat/fish and… Read more »
Jackie Kessler
4 years 5 months ago

Hugely appreciated this post, Mark. I’ve been noodling around with IF, but nothing to the point of having an impact on weight loss. But then, I’m still not fat-adapted, so there you go.

cis
cis
3 years 4 months ago

string cheese? That is not food…

Nicole
Nicole
4 years 5 months ago
I have dabbled in IF, eating only when I am hungry. I am a teacher, and getting up at ungodly hours sometimes renders me not in the mood for breakfast. It happens in fits and starts: sometimes I will skip breakfast three days in a row, other times I will go three weeks without missing my 2-egg omelet with cheddar, bacon, and spinach. Today, for instance, my tummy wanted nothing to do with breakfast — until I was on the road. I even looked at a Dunkin’ Dounuts with longing, wondering if I could just dismantle one of their newly… Read more »
new faster
new faster
4 years 5 months ago

I’m a pre-menopausal woman and have been experimenting with longer fasts this week. I perceive myself has having more energy and focus and being happier and calmer. I have always had problem skin and the fasting appears to be clearing it up. It does seem harder to lift weights when I’m fasted, though.

Stefani
4 years 5 months ago
Hi new faster. Stefani here. That’s wonderful! I believe that some women do great on fasting, particularly if they are not stressed or already very fit or at a healthy weight. I also believe that an occasional fast for all women might do them well. I do, however, caution women against listening to their bodies a bit in this case. In fasting, a woman’s hormonal response may take a while to become dysregulated. However, something that happens right away is that a woman experiences increased energy. This may be due to upregulated adrenal function– ie, adrenaline, in the system– but… Read more »
new faster
new faster
4 years 5 months ago

Interesting, thank you!

Brick
Brick
4 years 5 months ago

Ha! love that! Hormones! 46 years old…love the hormones…hate the hormones…nothing is consistent in my life and I often have to pick and choose which direction to follow in the primal lifestyle based on what my body is telling me. Thank you Stefani for talking about this. I am so tired of people expecting my body to react like a mans when it most clearly is NOT.
brick

Lindsay
Lindsay
4 years 5 months ago

I’ve noticed this for me. I’ll occasionally (one morning every few months or so) use fasting to increase my productivity for a work project when I have a lot to do and not much motivation, but it does leave me rather sleepless later that night. Like you mention, I’d read somewhere previously that fasting increases focus and energy, which is hypothesized to help us better seek out and find food. I think we tend to see more focus and productivity as a good thing, when that may not always be the case.

Barb
Barb
4 years 4 months ago

Thank you for this!! I am a 44 year old premenopausal woman who is, let’s just say,”not lean”. I tried IF and almost immediately stopped sleeping and experienced interruptions in my menstrual cycle.

I continued to IF, and things improved in the sleep and cycle department. However, since reading your article I have discontinued it, as I was not losing weight on it and also I realized that my body had trying to tell me something!

dill
dill
4 years 3 months ago

guess i’m going to IF the whole of my exam period then!

Lisaloo
Lisaloo
2 years 1 month ago

My HGH increases during a fast, and I sleep like a baby. Burned off 2 1/2 lbs last night while I slept!

Galina L.
Galina L.
4 years 5 months ago

It took me almost a year to be adopted to exercising in a fasted state. After adaptation it became amazing – like never be able to became tired.
I am 51, eating a LC diet since Nov.2007. It manages all my pre-menopausal symptoms and other health issues, like migraines, I’ve never got even a seasonal flue since I started my diet. IF is a part of LC eating for me. If you are adopted to ketosis, then practicing IF is the next logical step.

Carla
Carla
4 years 5 months ago
I am a 47yo female. I generally don’t eat past dinner (7pm or so), I work out early (6am or so) after a cup of coffee, and I don’t eat breakfast until 9am or so – some days not until 11 if I’m not hungry. It’s just what I do – I don’t (or didn’t) consider it IF, and it’s not something I tried to do consciously. Replying to vmckenna’s Mom’s response to fasting – I used to feel like that, before I started eating this way. Sick/headachy/mean after a few hours not eating. It made a huge difference once… Read more »
Saro Jane
Saro Jane
4 years 5 months ago

Evolutionarily speaking, why (and how) would men and women evolve to thrive under different circumstances/in different food environments? That’s the question on my mind since reading Stefani’s posts.

Thank you for writing about this Mark, I was hoping you would weigh in!

Erin
Erin
4 years 5 months ago
Well, just to take a stab at this… I’d have to say, in the traditional hunter/gather approach, since women didn’t wander away for too long to find food, they probably had more steady access to nutrients. It probably has a LOT to do with reproductive health too – Someone who’s pregnant or breastfeeding itsn’t going to be out hunting with the guys… Men probably adapted over time (and women) to the environment they were by. Women probably had more access to the nuts, berries, plants, roots, marrow, broths, etc., and men probably had more less access and were forced to… Read more »
Harry Mossman
4 years 5 months ago

Makes sense to me, although I think women did make long trips to known locations of food. Keep in mind that Grokina (and Grok) had limited means of carrying food home. You can hang a dead eland on a pole and two guys can carry it. What if you find some nice berries on the way to a melon patch. It makes sense that you eat them some. But if you are tracking an animal, you keep moving, maybe all day, or for several days.

Schmaif
Schmaif
1 year 9 months ago
If we’re talking purely hunter/gatherer people, and not idealized fictions, food on hunting trips isn’t as scarce as you might think. They brought along foods like pemmican, jerky, and anything else that could be stored and easily munched. When they caught their quarry, the first thing they would do is cut it open and eat the organs, which wouldn’t keep long otherwise. Some would eat the liver raw, others might start a fire to cook the heart, kidneys, and sweetbreads. Organ meat, being the most nutritious, was the boon of hunters. You can see in wild animals that hunt today… Read more »
Barb
4 years 5 months ago

It is really hard to say how it would have been back in the Paleo era, but I would imagine that women would not only have foraged for berries, nuts, roots and small animals closer to camp… they may have also done it packing an infant on their back and dragging a toddler along behind.

Also, it is a female’s nature (and I have noted this behaviour in modern times) for a woman to give her rations to her children and make due with no/less/inferior food herself.

lynn
lynn
4 years 4 months ago
My sister bow hunts for deer. She would never have stayed back at “camp”or “just” foraged for berries and herbs. She always gets her first shot and drops a buck where he stands. She can carry it out of the woods after she field dresses it. She is amazing. She has an IQ of 155. She uses herbs for healing. She knows where to forage for them even in the city. She would have packed her child on her back as she hunted and protected them with her life. At age 50 she can out lift and out work most… Read more »
Shona
Shona
4 years 3 months ago

I don’t think you should ask how they thrived, but how they survived at the worst times. What this difference points to is that in times of starvation, Females generally have a reduced ability to conceive. It makes perfect sense, since a pregnancy will leave the mother very weak if she cannot get enough food. Could miscarry or not have enough energy for delivery, or not be able to breast feed after, all these things killing the women and children of women whose bodies allowed pregnancy during starvation.

SuzU
SuzU
2 years 18 days ago
Well, this is something I do know something about! It has to do with the very different costs of reproduction for men and women. A fullterm pregnancy costs around 78,500 calories, and milk production costs 90.13 calories/100g. Lactating for four years (the average for hunter-gatherer societies and chimpanzees), plus the pregnancy, costs around 1 million calories. Add to this the costs of the supplemental foods gathered and prepared by the mother, and the costs of carrying the infant. Forager women do most of the provisioning of their children. All this adds up to a very powerful selective pressure toward women… Read more »
Michele
4 years 5 months ago
I gotta say, this kinda freaks me out. I’ve been doing IF for a few years now. I do one meal a day (dinner) which, for me is very satisfying because I enjoy eating large quantities and this allows me to do that without fretting that I am taking in too many calories. Am I hungry during the day? Yeah. Sometimes I am. But I hold out for my nightly feast. I am extremely active and lean but muscular. I have not had my period for about 3 years, but this was the case long before I started IF, when… Read more »
Emily Mekeel
Emily Mekeel
4 years 5 months ago

Are you eating enough calories? I’m not against feasting at one meal per day but if you aren’t getting in enough calories in that one meal, you may be doing your reproductive system a disservice.

Stefani
4 years 5 months ago
Hi Michele. I would ask about calories and your weight status, too. It sounds like you are possibly running in an energy deficit– one of the most prevalent causes of amenorrhea. In this case, it doesn’t matter when you eat–hence why you still were amenorrheic before–but how much you eat (I would argue however that when is still important.) There are a variety of things that can signal to a woman’s body that she is starving. Lots of exercise, low body fat, low caloric intake, possibly fasting, and possibly low carbohydrate intake are all culprits. As well as high stress.… Read more »
Michele
4 years 5 months ago
I am 4’10” and weigh about 107-110 lbs. I am small but muscular. When I eat my one meal I EAT. I honestly have no idea even ballpark how many calories I am taking in but I am always quite full when I finish eating. I am also on birth control but had been on it for several years before my period stopped. I also just got off crutches for a stress fracture in my hip which makes me think you could be right regarding my bone strength. What should I be doing? I’m also terrified of change and this… Read more »
Michelle
4 years 5 months ago

I am a successful, published fitness model, with a year round BF of 11% and competition BF of 8-9% and I have never taken hormones or lost my period. I know a ton of other women like me, so making a blanket statement like this about what is healthy for women just seems absurd in the face of reality…

maybol
maybol
4 years 5 months ago

i started if’ing in january of this year and haven’t had a period since. that’s 6th months. i’m definitely not pregnant. i’ve lost about 10lbs since and i’m active. i don’t think about it too much because i feel the best i’ve ever felt in my life. best mind, spirit and body i’ve ever had. every once in awhile i do think though…yikes. is this a problem?

Stefani
4 years 5 months ago
It can be. Not menstruating in itself is okay for health, but it DOES mean that your hormones are out of their desired balance. It also might mean that your adrenals are working overtime, which is why you are both losing weight and feeling really good. The best well known health risk of amenorrhea comes from having low estrogen levels, which leads to osteoporosis. Also, with amenorrhea, the uterine lining continues to thicken, such that endometriosis and endometrial cancer can become real concerns over the long term. Hormonal imbalance can also lead to insomnia, anxiety, and mental health problems down… Read more »
Marlla
Marlla
4 years 5 months ago

Hi ladies,
I had just recently had my blood tests done for the same reason, no period since August last year. I had been playing with IF only around 2 weeks before that so I don’t know whether it had any impact on the results or not. My estrogen level is very low and my GP recommends I go back on the contraception pill which I don’t really want to do to be honest.
Stefani, is there any other way how to raise my estrogen? Should I stop with IF? Thank you.

Jenny
Jenny
4 years 3 months ago

wow–that’s good to know!

Gráinne
Gráinne
4 years 5 months ago
It’s not OK not to menstruate. It’s really not. It’s a sign that something is wrong! Usually it seems to be the chronic caloric deficit rather than level of body fat that is the problem. Leigh Peele also says she sees it more in people who do lots of intense full-body workouts vs split routines. I’ve had stress fractures and they measured my bone density which was low in my spine. There is nothing that brings you back to reality faster than realising that you’re putting yourself at risk of fractures. What you do now is impacting your future. I… Read more »
Sharon
Sharon
3 years 11 months ago
I just wanted to add my two cents to the menstration conversation. I had lost my period on and off and than completely for close to a year. I was concerned about fertility and a loss in sex drive, and my obgyn just suggested BC or Colmatin (not sure on that name, but something to induce ovulation) as a “solution”. I wasn’t satisfied with that answer, so I went to a Integrative Doctor (wonderful, highly recommend, integrative medicine over western. More holistic, looking at all parts of the body and mind as interconnected) who did blood work and a saliva… Read more »
AS
AS
10 months 1 day ago

Doesn’t it really depend on her age (which she doesn’t mention)? She could be menopausal (pre- or not). This is a part of nature. Our hormones change because they are supposed to. Of course if she is younger, she might want to investigate other reasons, but menopause can happen as early as in one’s 20s. It doesn’t necessarily mean there’s anything else wrong. Also, there is a correlation between eating meat and dairy and lack of bone density. Look it up. Hope you feel better soon.

Lisaloo
Lisaloo
2 years 1 month ago

My HGH increases during a fast, and I sleep like a baby. Burned off 2 1/2 lbs last night while I slept! But, here is the thing, I have fat to burn. Fasted rats and people with nothing to burn aren’t going to do as well. The body will then burn protein, yikes, that is true starvation.

Ryan Hand
Ryan Hand
4 years 5 months ago
My wife and I have been doing a version of IF from the BulletProof Exec guy – basically coffee w/ Kerrygold butter & MCT oil for breakfast. I’m feeling great on it, and it helped push me past a weight loss plateau. But she’s getting an upset stomach from it and not going anywhere on her weight loss. I’m guessing she’s not fully fat-adapted yet. I just ordered her some super-enzymes per the Bulletproof guy’s recommendation. We’ve been primal for over a year now, but my wife takes more of an 80/20 approach. Is that going to prevent her from… Read more »
Stefani
4 years 5 months ago

I do not think it’s necessarily a matter of being fat adapted or not. Perhaps… I would suggest if you are both invested in this protocol that she go 100 percent rather than 80/20 and see what happens. (You never know, right?) Then you might know whether or not the fasting works for her. Perhaps she is one of the women who responds poorly to fasting, and instead of losing weight actually ends up with a body that responds by storing weight.

Laila Grace
Laila Grace
1 year 2 months ago

I am a 46 year old woman. Lost my cycle Dec 2014 and have been on a weight lose plateau for just as long. I decided to IF BulletProof style all last week and dropped 7.2 pounds without any struggle at all. I also got my cycle back. Go figure. I’ve got a new tool in my bag and I’m loving it because I felt completely in tune with myself, was more alert, acutely more aware of smell. My focus was off the chain, did not have hunger pains and saved $$$ on a weeks grocery bill.

Tania
Tania
4 years 5 months ago
Ryan, I respond the same way as your wife to IF – when I am without food for more than 4 hrs I feel very ill & get an upset tummy. I am 33, female & only been primal for 3 months and follow it 100percent! I have leaky gut which I think is a huge factor in why I don’t do well with IF. With a compromised gut I am unable to produce enzymes to digest food and make nutrients available for absorbtion so I need to eat 4 meals a day. Along with eating primal I am also… Read more »
Paleo Bon Rurgundy
Paleo Bon Rurgundy
4 years 5 months ago

What your doing sounds similar to the GAPS diet. Don’t forget to eat bone broth.

Lisaloo
Lisaloo
2 years 1 month ago

If I am not 100% primal, it takes about 3 days total fasting for me to get into ketosis and I suffer headaches and I feel tired and hungry.

If I am 100% primal, it takes a day and a night, very little hunger, and I wake up thinner and in ketosis, so I feel good.

I am a female, 45.

Lex
Lex
4 years 5 months ago

Eating very low carb and fasting made me an insomniac for the first time in my life and caused gobs of hair to fall out. I’m in my late 20’s and have PCOS. I think the prior symptoms have to do with increased cortisol.

Kayla
Kayla
4 years 5 months ago

I don’t have PCOS but I had the exact same issues. I started Primal with a low carb and occasional fasting regiment and it was not pretty. I’m in my early 20’s, and things got irregular, my hair, starting falling out and I started waking up at 3 AM every night. I upped my carbs and stopped fasting, and immediately things got better.

Kayla
Kayla
4 years 5 months ago

*my hair started falling out.

I hate when I don’t read things over before I hit post. 🙂

Elenor
Elenor
4 years 5 months ago
Waking up at 3 a.m. every morning is an adrenal fatigue (and possibly thyroid) symptom! (Read up at Stop the Thyroid Madness: http://stopthethyroidmadness.com/long-and-pathetic/) Look in the mirror and see if the outer-third of your eyebrows are gone/thinned )(thyroid). Hair dry and straw-like (and/or falling out)? (thyroid/adrenal) (Many, maybe most (modern) women have both thyroid and adrenal fatigue / problems.) I used to wake up feeling like someone had taken a bat to my kidneys (adrenal), the soles of my feet hurt (adrenal), my neck hurt and I was stiff and achy (adrenal/thyroid). WAY too sensitive to light and noise (as… Read more »
Lex
Lex
4 years 5 months ago

EXACTLY. I was just too lazy to explain it all. I’m very much in the beginning of fully healing.

Stefani
4 years 5 months ago
I would agree. I spend a lot of time researching and talking with women who are not overweight and have PCOS. I believe this is the case because we (I am one of them) have struggled with metabolic dysregulation and poor insulin metabolism in the past… and now that we have either lost weight or undertaken stressful diets and lifestyles, we have the additional “stop sign” on our reproductive system from this new angle. So far as I can tell from talking this over with women, the best solution is to eat a paleo, low-insulin, anti-inflammatory diet while simultaneously keeping… Read more »
Ashley
Ashley
4 years 5 months ago

Hey Stefani,
I first read about this on your blog and was surprised when I saw it here today! Can you elaborate on a “paleo, low insulin, anti-inflammatory diet”. I’ve had digestion issues for about 18 mos, causing me to be on a low carb diet, and now have low everything… Magnesium, testosterone, T3, B12, and amenorrhea. Being tested for candida too. Any guidance would be appreciated! And your blog is so informative! Thx!

K
K
4 years 5 months ago
Yup, me too. I lost weight on low carb primal with IF but my hair was falling out (A LOT) within 4 months. I’m in my late 20’s with PCOS as well. My cycle regulated during that time though and I felt great. I’m attributing the hair loss to the low thyroid effects of low carb. I now eat about 100g carbs daily, fast no more than 14 hrs (overnight) and don’t snack betweeen meals. This is lowering insulin and keeping my cycle normal and the weight continues to drop!… as long as I don’t snack or eat after dinner.… Read more »
Shea
Shea
4 years 5 months ago
I’m a pre-menopausal female who tried fasting during your series. I thought I was doing alternate-day-fasting, but as your series progressed, I realized I was doing it incorrectly. Basically, I skipped breakfast and lunch every other day or ever 2 days, for several 24-hour fasts each week. I did it for about a month and lost 5 pounds. I am one of your rare readers who did not experience weight loss when I went Primal (alone). I still needed to restrict calories, apparently. What I liked: it obviously worked for weight loss, and it gave me more flexibility for social… Read more »
Brick
Brick
4 years 5 months ago

That is a problem I find with IF’ing. If I skip breakfast I sometimes find myself over eating at lunch and I then find myself craving something sweet..as if I need a boost of energy…I don’t like that. But if I eat 3 meals a day for too many days in a row, my weight either maintains, or climbs 1-2 pounds…so I have to switch it up. Very frustrating, because I can not lose on Primal, but it does help me maintain.

Stefani
4 years 5 months ago
Hi Mark et al, Stefani here. First, yes!, I recently (this weekend) ran some stats on some new web analytic software and found that the one I have been using for years underestimates by 50-100 percent. (I had been using compete.com and just switched to Google software). My enormous apologies in that regard. Sincerely. I take intellectual honesty more seriously than perhaps anything else, so it means the world to me to apologize to you and convey to you that that was a mistake. And trust me, those low-ball numbers did nothing for my message, either. It would have made… Read more »
secret agent girl
secret agent girl
4 years 5 months ago

“I recently (this weekend) ran some stats on some new web analytic software and found that the one I have been using for years underestimates by 50-100 percent.”

I’m confused–underestimates *what* by 50-100%?

Lex
Lex
4 years 5 months ago

And just to clarify – a lot of people say they feel more energetic while fasting – I do too. But that isn’t necessarily a good thing just as drinking too much caffeine isn’t either. You’re making your adrenals work harder to produce more cortisol. And the body steals the building bLocks of progesterone and estrogen to do it. Not good! Stefani’s blog is a must read.

Mark Sisson
Mark Sisson
4 years 5 months ago

Lex, the cortisol thing is not so much a problem when you are fat-adapted. It’s when you are a sugar burner and can’t access and/or burn fat as easily that the adrenals are called upon to start the catabolic process.

Lex
Lex
4 years 5 months ago
I beg to differ. I did a very low carb diet – about 30 to 40 carbs or less a day while not eating any sugar for months – for a while not a tad. And that’s when the hair issue was at its worst. Also, when I started sprinting and weight lifting while eating this way I had insomnia. I could not figure out why I woke up after 3 or 4 hours until I understood I must have low cortisol. The body relies on that when blood sugar levels go low. If there isn’t enough cortisol your body… Read more »
Alana
Alana
4 years 5 months ago

What are some signs that can help me determine if I am ‘fat adapted?’

secret agent girl
secret agent girl
4 years 5 months ago

I’d like to learn this, too!

Stefani Ruper
4 years 5 months ago
Thank you, Lex, Mark. There is another issue for women at stake in this compared to men, in my opinion. Women often experience a fasting “high” of mental clarity, improved memory, and alertness (both rats and humans). While this feels great and I myself really enjoy using it, it is in fact a real evolutionary adaptation built in to prevent starvation. The female body (but not the male body) increases hippocampal activity in response to fasting conditions. For this reason other effects include insomnia and potential anxiety, depending on the degree of the starved state detected. The whole point being… Read more »
Lex
Lex
4 years 5 months ago

Thanks for responding, Stefani. I think this is such an important thing to get the word out about. In these comments and in the forums you see all these women saying, but I feel amazing! And I don’t want to burst their bubble, but I’m tempted to ask, but how long will you feel good? How long will it take for your thyroid to get so jacked up you start losing tons of hair. Maybe longer than me but it doesn’t mean we weren’t on the same trajectory when went super low carb and fasted.

Jodi
Jodi
4 years 5 months ago

I am wondering when you are speaking of these reactions to IF for women how long are the fasting states?

Jessica
Jessica
1 year 2 months ago

Hi Stefani,

Is this because IF lowers Estrogen and increases Prog in women?

Jodi
Jodi
4 years 5 months ago

Kudos to you Mark. The best teachers I know, are open minded, continue to learn and know… the more they know, the more there is to know. Great article.

karen
karen
4 years 5 months ago
For the sake of candor, I have fasted regularly since adolescence. I am 53 post menopausal and so healthy, it frightens me at times! The only times I ever missed a period was due to pregnancy. I have two children, 22 and almost 20; they were unplanned. They were full term and the labor for first was 1.5 hours and for the second 45 minutes. Upon entering menopause, even eating primal and exercising I gained a lot of weight, as I did with my pregnancies. 5’6” usually 127 pounds, then a high of 168 pounds with all vitals text book.… Read more »
SuzU
SuzU
1 year 8 months ago
Karen, sure, women in a particular group of hunter-gatherers would all eat much the same food. But they wouldn’t all respond the same way! Children (male and female) whose genetic makeup was less efficient for that particular diet would be more likely to die around weaning. Girls would take longer to reach puberty, have fewer children, and their children would be less healthy. Some 50% of !Kung San women don’t ever have grandchildren, and that’s the important thing. This effect of individual variability can be seen in non-human primates. Not all chimpanzee females thrive on the diet they all –… Read more »
yoolieboolie
yoolieboolie
4 years 5 months ago
Since becoming fat adapted I am less hungry in general. I eat WHEN and that usually ends up being a heckuva scramble and coffee or tea mid-day, a couple of snacks (handful of nuts, berries, or meat, or even a paleo-ized baked good I whipped up for the kids- gotta taste test ya know!) and dinner within the next 8-9 hours. – This pretty much evens out to me being 16/8 – 14/10 most days. I’m continuing to grow slimmer, sleeping better, constantly getting compliments on my skin, and my menstrual cycle is more regular and efficient than ever before… Read more »
secret agent girl
secret agent girl
4 years 5 months ago

Is WHEN an acronym?

Nicole
Nicole
4 years 5 months ago

Yup! Eating WHEN: When Hunger Ensues Naturally

Nicole
Nicole
4 years 5 months ago
Diane
Diane
4 years 5 months ago
I was able to do a 24 hour fast once a week when I was in my weight-losing phase. Now that I’m fairly lean (and eating somewhat higher carbs), it is too hard to go that long without eating. I attempted fast-5 style fasting and it totally made me crazy, obsessive, unhappy and hungry. I’ve decided that eating healthy primal food is best and to focus my efforts on improving my body composition through exercise. I’m sprinting and doing calisthenics which is new for me and giving me good results. I’m 47 and getting more toned and muscular and I… Read more »
N3P3N7N3
N3P3N7N3
4 years 5 months ago
I find that I ‘IF’ naturally, and have had no real ill effects. I actually feel that it has helped my postpartum body recoup faster than it did with my son. I only eat WHEN, and sometimes that doesn’t occur in a 24 hour period. Much like KM wrote, I usually feel better on fasting days then on days where I am eating regularly. I also don’t overeat after a fast, which can’t be said for my pre-primal state. I also used to suffer from hypoglycemia and fasting was absolutely not an option, as my body would shut down under… Read more »
secret agent girl
secret agent girl
4 years 5 months ago

“WHEN”–here it is again! What does it stand for, please?

SouthernFriedBB
SouthernFriedBB
4 years 5 months ago

WHEN = When Hunger Ensues Naturally

Teresa
Teresa
4 years 5 months ago
Mark, I found this article very interesting and informative. I am a 49 year old woman who is pre-menopausal (I’m guessing). I’ve been struggling with my weight (I gained 30 pounds after 3 rounds of prednisone for serious allergies) after I had my 4th child at the age of 42. Lots of things going on there…my thyroid numbers are “normal” by in a range that could, according to new studies, be indicative of hypothyroid. I haven’t been able to lose the 30 pounds (plus the other 10 or so that I still wanted to lose after my daughter was born.… Read more »
Carla
Carla
4 years 5 months ago
Off the IF topic, but I wanted to reply… Theresa, I have found that adding a little bit of high-energy movement every the day helps a lot. I also have a sedentary job, tho I follow Mark’s workout three days a week (body-weight exercise M,F, sprints W). I have been adding just a little more movement to each day, lately. Swimming a half hour a couple times a week. Hula-hooping for 10 minutes a few times a week. Jumping rope every once in a while for 5 minutes. It is still an effort for me to remember to do it,… Read more »
Judy
Judy
4 years 5 months ago

As a woman on the other side of 50, I consider myself doing the IF when I put off breakfast until 10:00. I find it too over-welming to think about fasting for extended periods of time (which for me would be anything over 12 hours). I also have a teenage daughter that I am trying to model good eating habits for. She seems to have a healthy body image so I guess I don’t see IF as an enhancement to our lives.

Teresa
Teresa
4 years 5 months ago

That being said, I have tried IF…fasting until around 11:00 AM and have had no problems with it at all. Not sure I’ve seen a benefit, but no problems either.

Teresa
Teresa
4 years 5 months ago

Oops—that was supposed to be an additional comment for my previous post.

Doghug
Doghug
4 years 5 months ago

I have fasted with no problems. My type of fasting is when I’m not hungery and a mealtime comes around a’ll just skip that meal.

MamaGrok
4 years 5 months ago

Another major caveat I’d give to IF is that people who struggle with cravings and binges (REAL binges, not just choosing to have a handful of cookies once in a while) should not fast.

But eating a big protein breakfast over time kills the cravings and naturally reduces hunger, so that now I’m naturally skipping lunch every day, with no hunger, and none of the increase in cravings I always used to see when I tried IF w/o the high protein&fat bkfst.

Doghug
Doghug
4 years 5 months ago

opps 🙁 it’s I’ll not a’ll
sorry about that.

Happycyclegirl
Happycyclegirl
4 years 5 months ago

One of my issues is getting cold when fasting. Only happens once I hit the 12 hour mark. Other times it doesn’t bother me at all. I think eating sugar as part of my last meal (ie fruit, honey, maple syrup and sugar) is what is doing it.

I really try the WHEN approach. It feels so much better to me then any other type of IF.

qqemokitty
qqemokitty
4 years 5 months ago
I am 28 (fem) and I started a 24 hour intermittent fast (eat at dinner time) around 3 weeks ago. I have had no problems with it. Occasionally I feel hungry, if I drink some water it tends to go away. It’s made me feel good overall. If I do get actually hungry, I will eat during the day. And on my nature hikes on the weekend, I break my fast with bacon and eggs before going, to make sure I have fuel for the exercise. I think IF is great (though my family hates me doing it) and it… Read more »
Oceanside Grokette
Oceanside Grokette
4 years 5 months ago

Weird that your family hates on you for doing it, mine does too. I can’t figure out WHY, lol. Maybe it’s just too much blasphemy against CW, dunno. I’m close to you in age and also a gal.

Mikki
Mikki
4 years 5 months ago
I’m 45, primal for about 3 years but still a bit over my desired weight- but I’m insanely chronically stressed, so I’m OK with maintenance until I finish my dissertation. At some point I’d seen some research to suggest that men do better on ~17 hr IF, while ~14 hr is better for women. I’ve definitely found 14 hours to be my sweet spot — much longer and even if I don’t get hungry, I get jittery and scattered. I don’t plan my IF, rather let my body be my guide — I bring a meal to work, and when… Read more »
Vanessa
4 years 5 months ago
I have been intermittent fasting since October 2010. It wasn’t intentional, but just kind of happened. My pattern is typically a 14-18 hour fast and then two large meals with the occasional snack. I have been a low-carber for more than a decade so I am definitely fat-adapted. In the same time period as I have been fasting I also have been in the final leg of recovering from adrenal fatigue. My doctor is aware of my low-carb and fasting status and is fine with it. In fact my most recent salivary cortisol was the best it has been in… Read more »
secret agent girl
secret agent girl
4 years 5 months ago

Can you say more about the “very comprehensive lab work”? Like, what you have tested and whether you go directly to an independent lab or how you get your doctor to agree/order testing, etc.

Is that how you know about your micronutrient levels?

Christine
Christine
4 years 5 months ago

Had to chuckle when I read this. I’m peri-menopausal and didn’t realize I was basically fasting (14/10) until I ran into a horrible bout of insomnia — waking up between 1am & 3am and not sleeping much after that. Turned out that I was waking up because my body was freakin HUNGRY, even though my stomach wasn’t rumbling. Had to add a bit of starch/fiber to my diet (primarily sweet potatoes) and I no longer worry about wanting a snack before bedtime — sleep is back. No fasting for me — too stressful on my system.

Abby J.
Abby J.
4 years 5 months ago
I’m so glad to see this article! I personally have experienced good weight loss results with IF every once in a while after a weekend of indulgence or too much straying off the blueprint, but the successes were generally very modest ones. My husband, however, has great results with IF. After Mark’s series, I gave fasted weight training a try for the sake of experiment and gave it up after a few goes. I just don’t do well on heavy lifting days when I’m fasted. No strength, no muscle recovery in between sets – I much prefer to be fed.… Read more »
Roberta Saum
4 years 4 months ago

I never did well working out fasted either. My workouts were lame when fasted. I much prefer fed workouts and I’ve had great results as well. The shape I’ve gotten into speaks for itself.

Roberta Saum
4 years 4 months ago
I recently said I could not work out fasted. Well, I finally tried it again two weeks ago and I’m working out fasted now and it’s AWESOME. I’m not sure what changed. I’m thinking my mindset. I’m too lean to do 24 hour fasts anymore. I can do them but I tend to want to eat everything in the fridge for a couple hours after each meal for several days afterwards and that is just torture so I stopped fasting. Since I can’t do the longer fasts, I decided to try working out fasted first thing in the morning and… Read more »
Ann
Ann
4 years 5 months ago

I would have never believed that fasting can come naturally (without forcing yourself to NOT eat). Only two weeks into my experimenting with eating primal, I wasn’t hungry. I skipped eating for one whole day.

Getting over carbs was also interesting. I ate oatmeal with flaxseed for breakfast for over 3 years, so switching to eggs and bacon was wierd. I felt like I was cheating on a diet or something.

Becky
Becky
4 years 5 months ago
22 year old, very lean female. Into weight training, parkour, and general athletics. I tend to, like Mark, use IF as a tool. If I’m traveling, at a non-Paleo dinner party, or don’t have time/supplies to pack my lunch or funds to eat out. Probably once or twice a month. I haven’t had any trouble fasting, it really comes naturally and I even find it a bit rejuvenating. I tend to scale down my workouts but honestly I have plenty of energy. Side note: I did not lose weight when I went primal (didn’t have any TO lose) put actually… Read more »
Sangita
Sangita
4 years 5 months ago

Once again life made easier by Mark!

Paleolady
Paleolady
4 years 5 months ago

I’m not sure that skipping a meal twice a month is considered fasting? The article posted by Stefani from “Paleoforwomen.com” was about the problems females tend to face when regularly fasting and for much longer periods of time. I think she would agree that skipping bad meals is a pretty good call.

Monique DiCarlo
4 years 5 months ago

Thanks for this insightful post Mark! I’m also grateful for the idea to not eat when you’re not hungry, it makes sense! Several times a week I (47, 5’8 and 150, from the Netherlands) do not eat after 7 pm and then start eating 11 am the next day. I believe that is considered a fast? Only since I started eating Primal I can do this very easily and love the “clear” feeling it gives. Would like to lose 10 pounds, hope this short fasting will help, besides doing more exercise. XOMO

Cat
4 years 5 months ago

The one and only time I made a conscious effort to IF, my body really wasn’t happy.
I track my body temps and noticed that they really plummet if I’m fasting which can’t be a good thing. Also I’m tired and cranky.
Having said that, if I just don’t eat because I’m not hungry I’m generally fine.
Conclusion: IF is not for me, I’ll continue to just listen to my body and pay attention to its cues.

Elenor
Elenor
4 years 5 months ago

One way to test and track thyroid ‘operation’ is through temperature tracking. My temps (still) are always well below 98.6… Before I treated my adrenals and thyroid, I was usually around 95-96; and no enzymes work well at that body-temp! Higher now, but still not “normal.” And yes, I’m still taking T3-only thyroid pills (down to one a day though — from six a day at my highest!

Audrey
Audrey
4 years 5 months ago

I’m a woman and I just do it naturally… sometimes I just won’t want to eat for twelve hours or so and not be particularly hungry in general, and other times I’ll just need to eat a lot. I find the latter is dependent on hormones.
I have a circadian rhythm disorder as a confounding factor though, so it’s possible that my eating cycle is not properly in line with my sleep at any given time.

Rachel
4 years 5 months ago
Having found intermittent fasting a massive struggle before committing to Primal eating, I confess I raised a sceptical eyebrow at the notion I might someday find it so natural I’d do it without thinking! But nowadays it really is pretty much effortless. I stick in the occasional timed fast if I feel I need one, but something I love about the “not IF, but WHEN” approach is the even greater freedom from counting – first calories, now hours since last eating! Not sure what the claim is for women not fasting, but considering we have higher body fat to draw… Read more »
Heather
Heather
4 years 5 months ago
I’m with you Rachel. I am 50, only vaguely aware of my cycle as I don’t have a uterus anymore, but I eat WHEN, and have since I did the Leptin reset, and then went primal, have been for about a year. I usually start the day with a coffee and cream (yum), then eat when hungry, about lunch time. Then cook for the family. I feel liberated from calories routine and guilt, and the kilos are slowly coming away. My PCOS symptoms are gone along with a whole host of other things. My sleep is a bit ordinary at… Read more »
Momto3
Momto3
4 years 5 months ago
I tried fasting with the 10/14 window. It did not go well for me. I was constantly hungry even though being low carb high fat. I gained a bit a weight or stalled completely. Now, the context for me is that I have PCOS ( hormone imbalance) and I did not meet the pre-req in the sleep department. ( waking with baby) My take away is that fasting regularly is not for me right now. With three young children I have plenty of stressors. Now, that said, when circumstances call for it, I can go much longer between meals if… Read more »
Harry Mossman
4 years 5 months ago

I am a guy who stubbornly resisted fasting for 2 1/2 years because I was getting pretty good results. After starting mostly eating in a mostly 11 am to 6:30 pm window, I am getting fabulous results. Fat melting off and twice as much energy. I think IF is essential for guys (after becoming fat adapted, which is also essential.) That’s how we hunter Groks evolved.

But it is wonderful to see some thought about how women differ. Too little of that in medical research.

Harry Mossman
4 years 5 months ago

Crosses off the extra mostly.

Toshia Parker
Toshia Parker
4 years 5 months ago
I’m a 40 year old female. I’ve been primal for many years. I have to agree that complete fasting has never worked well for me. However I do find that making sure that I fast for 12-14 hours each night from 7 pm on and working out right away in the morning at 60 % of my max heart rate for 30 min before eating anything and waiting at least an hour after my workout to eat a primal breakfast has really helped me on my way to trimming the last of the stubborn fat. I have dropped double digit… Read more »
Brad
4 years 5 months ago

Great stuff!

Yes, that is a great way to practice IF for many people. Others i know prefer to eat lots at night and eat little or nothing in the morning hours. Both work.

Grokvamp
Grokvamp
4 years 5 months ago

I am glad to hear this! I can naturally IF as long as I allow myself to eat heavy at night. I have trouble shaking the notion that you have to eat your biggest meal in the morning. Maybe my natural window of eating is 1pm to 9pm.

Lia Parker
Lia Parker
4 years 5 months ago

Reading these posts just makes it even more clear there are differences even amoung individuals. We are each so different in how our bodies handles IF.

Linda
Linda
4 years 5 months ago
I think that too many women interpret “IF” for “intentional starving”. I tend to go a day without food – or IF after a big food day as a result of a large family gathering or Sunday football or whatever- basically a cheat day. Honestly, I am not hungry the next day and IF just makes sense for me. It also gets me right back on track with my diet and weight. I strongly believe that some women read about IF and they’ll under eat overall and then not eat for a full day or more than a full day… Read more »
Linda
Linda
4 years 5 months ago

And I should mention that I 46 and Peri-menopausal.

gibson girl
gibson girl
4 years 5 months ago
I’m 62, post-meno, diabetic (no meds), pcos, met syndrome. I have good blood sugars, labs and have been IF between 14/10 and 16/8 for more than a year. I start the day with coconut oil and have a good protein lunch around noon. Between five and seven I’ll have a bowl of berries and nuts with more coconut oil. I feel fine on that schedule, but I haven’t lost any weight for ten years. I could lose 50-60 pounds yet but everything stopped at menopause. :p If this is hard on adrenals, I’ll start eating a light breakfast again! Sleep… Read more »
na
na
4 years 5 months ago

Till last year, I was fasting ~16 hours everyday for 45 days on a sugar adapted body. I never experienced any side effects. I am very lean with body fat around 17 – 20%(keeps varying every year). I usually let go of exercise completely during fasting because my sugar level drops too low.
I have to fast every year because of religious reasons(I’m a Muslim….and we fast for an entire month called Ramadan). This year I’m more paleo than before, so I’ll be on the lookout for what changes occur in my body while fasting.

na
na
4 years 5 months ago

Forgot to mention I’m 29 and a female 🙂

Aloka
4 years 5 months ago

I follow most of Mark’s advice but in 2 years haven’t really done IF. just did not come to me naturally and I wasn’t comfortable when I did force my self to try it. So I guess it really depends on how you feel and the results you’re getting and if you feel you really need to push your self enough to try it. If you’re happy with what you’re doing and the results you’re getting you may not want to push yourself that far.

Jana
Jana
4 years 5 months ago
I’m a nursing mother and with my first child I was concerned about the fasting requirements of my faith (Catholicism) during the season of Lent (every Friday no meat and only two small meals that when combine do not equal a full meal). I had no idea what a fast would do to my already taxed body. Then I found a fellow mom blogger who posted her results which were not good: http://awomansplaceis.blogspot.com/2011/03/nursing-and-fasting-just-dont-do-it.html?m=1 The Catholic church does abrogate children, pregnant moms, nursing moms, and the elderly from participating in a fast. I think it is important to know what will… Read more »
Shary
Shary
4 years 5 months ago

I’ve never had much faith in rat studies because rats are rats, not human beings.

After quite a bit of experimenting, I find that what works best for me, a female, is a light breakfast, a light lunch, and having my main meal unfashionably early in the evening, say 5:30 p.m. or so. I don’t snack or eat again until around 8:00 a.m. the next morning. As far as I’m concerned, this is enough of a fast.

Tammy
Tammy
4 years 5 months ago
Well I’m a 43 year old female (5’6″ 135 lbs) and I’ve dabbled in IF over the past three years. It does work best for me when I am totally random. I am fat-adapted and always do my workouts first thing in the morning in a fasted state. I’ve had really good strength gains this way and some weight loss. Most of all though I just try to pay attention and eat when I am actually hungry. I will say that it is is much easier in the winter time, when I generally am less active and sleeping more. In… Read more »
Charlene Fannin
Charlene Fannin
4 years 5 months ago

How do you know when you are “fat adapted”?

secret agent girl
secret agent girl
4 years 5 months ago

Ditto the question. It would be great to have a page of definitions/brief explanations of the jargon used on this site.

Brick
Brick
4 years 5 months ago
Finally! I can’t tell you how many times I would read a discussion or get involved in a conversation and some well meaning man will tell me how my body is suppose to work. I am a 46 year old woman, 8 years of perimenopause. What works for me one month is no guarantee it will work the next month. I have done the IF. I can’t do it regularly..although it would be very easy for me to do so. In fact I would prefer to skip breakfast altogether, but when I do my body puts weight on. I have… Read more »
Hopeless Dreamer
Hopeless Dreamer
4 years 5 months ago

brick – there is a thread on the forum for women over 50, but anyone can chime in. You may find some other women going through the change with advice or at least sympathy for you!

Brick
Brick
4 years 5 months ago

Awesome! thank you…I didn’t know of that forum..

brick

Stefani
4 years 5 months ago

Hey Brick! I’ve had posts stewing in my head on paleo, womanhood, and menopause for quite some time. They’re coming on my end, promise. 🙂

Stefani

wpDiscuz