diets · eating

Intermittent fasting and why it might not work as well for women

You’d have to be living under a rock not have noticed the latest diet trend, intermittent fasting.

It’s gone from making the rounds in the Paleo community (see Intermittent Fasting And The Paleo Diet) to mainstream with the 5-2 diet. See British 5:2 diet craze heads to the US. See also When you eat key to intermittent fasting (CBC).

The basic idea of the 5-2 version is that you “fast” for two days and then eat whatever you want for the remaining five. It’s not strictly speaking an actual fast because you do eat about 500 calories on the “fast” days.

There are many versions of intermittent fasting (or IF as many fans call it) from some that sound just like skipping breakfast, to others that have a more complicated structure throughout the week, to some that are geared to a very specific purpose such as avoiding jet lag.

The evolutionary basis of this approach to eating seems obvious. Humans have evolved to do well in feast and famine conditions. The problem with the contemporary North American diet is that it’s all feast, all the time. Many cultures around the world practice fasting and seem to suffer no ill effects from periods of fasting, followed by periods of feasting.

It’s striking how much IF deviates from the regular feeding, three meals + two snacks, of most other nutritional plans for athletes, including fitness competitors and body builders. On those plans you eat regular small meals, not going more than three hours without food.

But arguably the fasting habit isn’t for athletes. As you might imagine there’s been controversy over this. For the argument against IF for athletes, see here. The argument against relies on the large amount of data we have on the performance of Muslim athletes during Ramadan. Short version: athletic performance suffers. Also athletes need fuel to train. See that argument against here.

And of course, some athletes and coaches think it’s terrific, if done right, read more here if you’re interested.

Regardless most advocates and fans of intermittent fasting don’t have athletes in mind. The 5-2 diet is described as being perfect for the average person, no big changes in what you eat required, except of course on the two fasting days.

Is this just the latest fad diet? You should read what Tracy thinks about fad diets and the meaning of success here.  Does it work? Again, as Tracy says that depends on what you mean by work. She’d likely tell you to try intuitive eating instead. Intermittent fasting is kind of the opposite of intuitive eating. Rather than noticing and hunger and eating when you’re hungry, on a fasting diet you follow the clock, not your stomach. You learn to notice hunger and then ignore it.

There are lots of versions of IF out there.  Anthony Mychall does the Warrior Diet–one meal a day. He writes about it in this blog post, How to Start Intermittent Fasting and Kick Hunger Aside. How to cope with hunger? “The best way to forget about hunger is to literally put yourself in a position to forget about hunger. Keep active during your fasting window and put yourself in a situation where you can’t eat. Hell, sleep in if you have to.”

What about more extreme versions? In Inhuman Experiment: An experimenter in search of prolonged youth we read about another IF propocol. This one requires 24 hours of fasting as it’s based on alternate day feeding, called ADF, of course. See the blog post, Intermittent Fasting: Understanding the Hunger Cycle for more about hunger: “The feelings of hunger during intermittent (24 hour) fasting vary with time. The one thing to keep in mind is that, in my experience, the most difficult part is near the 20th hour into the fast. That’s when the hunger is replaced by a general lack of energy and focus. This feeling will, however, pass in an hour or so, after which fasting becomes much easier again.”

I’ve often thought of intermittent fasting as one tool in the careful eater’s bag of tricks. I do a version of IF I suppose (though I’ve never called it that) when I decide to not eat after dinner, thus lengthening the period in the day when I go without food. I do this on days when I’m not working out in the evening. I go to bed a little bit hungry but since I always wake up hungry no matter what there doesn’t seem to be any other change in my desire for food.

A few years ago on the advice of a personal trainer I experimented with morning workouts on an empty stomach but that was a bit of a disaster. See comments above on waking up hungry! Halfway through my morning run I was prepared to go knock on doors in search of breakfast.

I’ve had more some success with eating lots less when I travel. It’s a good time to experiment since the food options are crappy and expensive. I haven’t tried IF as a way of combating jet lag though I might the next time I head to England or British Columbia.

On jet lag and fasting. read more here:

But one thing seems clear about these various eating schemes, your mileage may vary: what works for some doesn’t work for others. If regular  intermittent fasting is successful for you, great, but there are concerns it doesn’t work as well for everyone and very specific concerns that it doesn’t work as a nutritional strategy for women.

I read Shattering the Myth of Fasting for Women: A Review of Female-Specific Responses to Fasting in the Literature and was shocked that for all I’d heard IF touted as good for people, most of the research supporting IF had been done on men. Surprise, surprise. For the effects of fasting specifically on women you need to read about studies with rats and mice, and the news isn’t good. Women, it seems (well at least female rats and mice) don’t get the same benefits from fasting and they suffer some additional ill effects.

Yet, I’ve had intermittent fasting recommended to me by several young men, heavily involved in fitness and nutrition.  In light of these experiences, I was thrilled to read a terrific rant (she gives the best rant) by Krista Scott Dixon, at Stumptuous.

In “The First Rule of Fast Club” she  rants about and aims fury and righteous rage in the direction of lots of things including the following: why intermittent fasting may not be the cure all for women’s weight woes, why in general what works for young men won’t work for women, and why women shouldn’t listen to young, thin, male personal trainers.

“The first rule of fast club is: Don’t talk about fast club.

The second rule of fast club is that skinny guys no longer get to tell me what to do. (Although I love you guys. You look so cute with your pants falling down!)

I come not to bury young male ectomorphs, but to praise them. In fact, I married one. They are a fascinating species. I have observed my own specimen for years, like Jane Goodall amongst the chimps.

Here are some interesting facts about these wonderful creatures.

1. Many of them can live on fumes. Craving neither food nor drink, these hominid hummingbirds apparently draw nourishment from the air. They sup on dew and dine on dust.

2. When they are stressed out, they don’t eat. Actually, when they aren’t starving, they don’t eat. Which is to say, most of the time. Can you believe not eating when you’re stressed? I know! Ha ha! Crazy! I keep trying to explain to my specimen that giving a loaf of bread a butter enema then dipping the whole thing in chocolate and rubbing it all over your esophagus will always make you feel better. Thus far I have failed to convince him.

3. When they do eat, it doesn’t seem to matter. Have you seen the food these guys can put down? It’s like they encode for some MAKE_ABS1 gene. In their bodies, somehow cookies turn into tummy bumps.

4. To lose weight, they do crazy shit like give up drinking so much beer. I hear women from all over the globe gnashing their teeth at their partners’ superhuman abilities to get riptshizzled with no effort. I’ve been busting my ass and I lost 1 lb in a month! That jerk’s doing my nutrition plan along with me and he’s lost 40 lb in the same time, just by eating one less strand of spaghetti a day! I hate him!

I hear ya. My home dinner table conversation sometimes goes like this.

Me: Ugh, I feel the estrogen demons again. I feel like an inflated wet sponge. The only thing that fits me is the Snuggie my grandma gave me last Christmas.

Him: I don’t feel so good myself. I had a whiff of anxiety today and dropped 5 lbs. Then my shirt tore itself on my abs.


There there ladies. Cry it out.

And here is point #5, which may be the most obvious:

5. They are not us.”

Go read the whole thing here.

Here’s a very useful resource if you’re thinking about giving intermittent fasting a try: Precision Nutrition, Experiments in Intermittent Fasting.

Have you tried Intermittent Fasting? What do you think? How did it make you feel?

31 thoughts on “Intermittent fasting and why it might not work as well for women

  1. I had a phase of fasting (no food, just water) for one day each week. This was long before I became disabled. I didn’t believe in slimming, back then, and my weight was stable at a level appropriate for my height. My reason for the weekly fast was more about finding myself. I was keeping a dream diary, reading self-help books, meditating and so on.

    What I found was that after a few hours of gnawing hunger, I’d hallucinate. So it worked for me as part of finding out who’s living inside this head! One time I kept on with the fast for a whole week and it was like having my skin peeled off – not in a painful way, but heightened awareness of everything.

    Writing this comment, I realise that I don’t remember my first meal after the long fast. So it can’t have been very memorable! Not like the first meat meal I had after 4 years of vegetarianism, which was delicious but made me throw up. Eating 6 pork chops into a stomach that hasn’t had meat for years is not to be recommended! but that’s another story.

  2. I’ve never really “fasted” though I’ve had lots of practice with starving myself on very few calories a day for weeks or months at a time. I’m quite convinced by all that I’ve read lately about food as fuel for stoking that metabolic fire, and am wary of anything that calls for interrupting that. Also, the main point of it seems to be weight loss, and these days I’m more about muscle gain. You’re right that I’d encourage intuitive eating — or really any kind of eating! — over fasting. Your point about fasting (or eating less) while traveling is interesting. I usually pack a PBJ sandwich or a cliff bar these days, and if possible a few pieces of fruit. I get quite panicky when I need food and can’t find it (as a vegan, this happens when I don’t plan ahead while traveling). Then I start to feel headachey and ill, and after that I’m no fun to be around. So I can’t imagine doing it for days in a row, though of course lots of people do.
    Argylesock’s experience of hallucinations isn’t a big selling point for me, but I like the idea of heightened awareness. I’ve achieved that during my summer yoga sadana, when we practice together at the studio from 6-7:30 every morning for seven days. Everything looks crisper and clearer, and I’m more sensitive in all of my senses.

  3. There are lots of different IF protocols, for different purposes. Some seem beloved by athletes who need to “make weight”–think competitive rowers, martial artists etc–and others are recommended as ways for the average person to lose weight without much changing what they eat. (Heaven forbid.) Those motivations for IF are both weight loss focused. The two motivations that I’m curious about and plan to blog about are jet lag (sounds fascinating) and making peace with hunger. I’d like to treat hunger more neutrally, as less of an emergency. Fasting is a way of seeing that nothing disastrous happens. But neither of those motivations is a motivation for regularly fasting. There I’ve got concerns about the research and about women’s bodies. So fascinating and sadly typical that all the research was done on men yet the diets are recommended to men and women. Krista’s column, linked above, is definitely worth reading. So is the Paleo women one. I don’t think occasional fasting puts one’s metabolism at any risk. What does that is sustained low calorie eating, regularly eating far fewer calories than you body needs. But again I suspect this varies from person to person. Other than not eating after dinner, and trying it out for jet lag reasons, I’m not planning on fasting either.

  4. I’ve tried a simple IF protocol a few times over the years, at most three days/week. I ate an early dinner (say 5 pm) and then skipped breakfast to provide roughly 19 hours without eating before lunch at noon. I never lost weight while doing it, probably because I ate more the next day. I wasn’t tracking then. Most of the time with IF I felt light (which I associated with “good”), but I also felt anxious and overcaffeinated (without caffeine). IF did not help my weight training. I was considering it again because of all the positive information about it on the web and from my trainer, but then I found the paleo for women article you cite. Ah, of course. It’s good for men. I won’t IF again.

    1. Thanks for sharing your experiences. Seems to be a wonderful thing for men and ‘meh’ for most women.

  5. I am so happy that somebody is raising their voice on fasting and that many women’s experiences are similar to mine! I am vehemently opposed to religious fasting, as long as it is imposed by a religion devised and run by men. A woman can, obviously, choose to fast, watch the outcomes and decided if that’s right for her. However, one of the reasons why I believe that fasting is wrong for women in their menstrual years is that menstrual cycles works non stop, and at each stage we each woman needs particular intakes of food, liquid and so on. Again, that cannot be imposed. some of us prefer to eat some fruits and drink a mint tea when we are bleeding, some seek comfort in nice foods. In the stage after bleeding and before ovulation I am usually so energised naturally that I don’t need to eat. However, as I tend to get busy in this period, I might get ravenous. And so on. One cannot deny a woman’s body energy when it is building uterus’ lining, nor when it’s releasing an egg. Each stage is challenging for a woman’s body and each presents its own demands. Fasting that is imposed from outside and that ignores women’s cyclical nature is wrong.

  6. I have been doing a type of intermittent fasting for the past few weeks and I like it. That being said, I am not going for 24 hrs without eating but rather eating my decreased calories for in a 10hr period and then not eating again. Is it really IF, probably not but that sounds like a good thing to call it for now. I think like in all things, moderation is the key, if you eat more than you use, you are going to put on some weight. There is no one thing that works for everyone, find what works and go with it.

  7. I don’t like the word “fasting” in the first place. It’s just unhealthy. For myself, I just call it eating less. Or sometimes I just forget to have a particular meal. Or 1 big meal counts for 2 a big breakfast. I don’t call fasting ….unless I want to sound hip/chic. Which I don’t.

    The only time I’ve fasted was for blood testing purposes. That’s it.

    Anyway, I don’t plan to use the term “fasting” …my doctor-sister will think I’m nuts. Besides that’s monkeying around with my metabolism and putting my body in starvation mode to burn calories more slowly. Which it IS.

  8. I would like to add that doctor-sister lost 50 lbs. and she NEVER fasted. She changed to different types of foods and took up jogging.

  9. I never fast to lose weight. When I fast I pray. I have not done it for more than 24 hours/maybe a bit more. There are times I do it with no water, other times I do it with water.

    1. Usually after the fast, I usually have a cup of tea or I eat something light. I notice my body is reacting to this differently now.

  10. I can’t stand these stupid diet trends. If you exercise and eat a healthy diet, you shouldn’t have to starve yourself a few days a week. It just perpetuates the whole idea that the ONLY way to be slim is to starve yourself. I’ve always been very slim. I grew up doing martial arts and being very active, and I carried this on into adulthood. I’ve always eaten a very healthy diet too. When I was young, chocolate, sweets and coke were treats and not staples of my family diet. However, for as long as I can remember, I have had people telling me that I must starve myself in order to be so slim.

    Conversely, I actually eat a lot because I’m so active. I eat a lot of protein, low GI carbs and whole grains. My appetite varies with my activity levels. I also lift weights and have a decent amount of muscle on my body. Muscle is vital for weight loss/maintaining a healthy weight. Each time I see a girl in the gym lifting 1kg dumbbells, I want to scream.

  11. “Eats one less strand of spaghetti” and loses weight. Ha! That is SO my husband. Life is unfair.

    I usually fast once a week, for a number of reasons. I find it beneficial. The thing to remember is, we are all different, we don’t operate exactly the same way, we don’t have the same goals, or the same definition of “healthy.” While I totally subscribe to the idea of not taking fitness advice from skinny young men, I don’t *automatically* take it from someone just because she’s a woman. I’m not the same as every other woman; we are not one monolithic entity. When it comes to nutrition, my approach for a good while has been: Try it and see what *I* think about it; how does it work for ME. Because all the theory in the world means nothing if it isn’t right for me specifically.

      1. Whenever I gnash my teeth at my husband’s nearly-effortless fat loss and muscle gain, he always says something like “but you have the larger brain.” Which is sweet of him 🙂 But I still want to kill him…

  12. It seems to me like fasting for two days of the week would also be a terrible idea for anyone who does physically demanding work, not just athletes. You wouldn’t want to faint on the job; you might get fired.

  13. I’ve been if fasting for the last month and I love it. I’ve lost 13 pounds so far and I feel great. I still eat the same amount of calories as I would normally. I just stop eating earlier and excersise. I say if you want to try it go ahead! Don’t let other people’s opinion deter you. If its something you want to try do it. Take it from a woman whose been trying to get weight off for years!

    1. Hey Starr, I’ve been doing it for a week and am feeling good since I’ve lost a pound. I’m very interested in what your IF process was – how many hours and did you consciously make sure you had sufficient calories?

  14. My husband and I have been doing the 5-2 for ten weeks now. On Mondays and Thursdays we eat 600 (men) and 500 (women) calories respectively. He’s lost 13 lbs and I’ve lost 10. I think it is something we can live with for the rest of our lives. We were both about 30 pounds overweight so we’re looking forward to more weight coming off slowly but this is very effective and has many nice side effects. Not having to cook two days a week, being conscious of which foods are healthier and lower calorie, and just finding something that works without a lot of fan fare, expense, or temptation is such a relief. I don’t think we’re doing ourselves any harm and we’re looking forward to the the next cholesterol check. We usually eat a poached egg on GF toast for breakfast, piece of fruit for lunch and vegetable salad for supper (no dressing, maybe slice of avocado) all you can eat.

  15. I’ve been doing the 16/8 IF and I love it. I was doing it by accident and decided to look into fasting and I came across some great information. I needed to make sure I was safe doing it since I’ve always read that going without food longer than 3-4 hours will ruined your metabolism or eat at my muscles that I’ve worked hard for the past 5 years I. I just get so tired of eating all the time. I love food when I do eat it but it is so exhausting trying to eat healthy every 2 -3 hours. When I was younger I never ate after 7pm, slept til 5:30am, went to school and ate lunch at noon and I felt great and was thin. I never weighted myself and did’nt care to. The day of my accidental fasting, I got to thinking that our ancestors didn’t have a fridge full of food and went long periods without food and they were fine. Strange for me not to want food often now that I’m older because I usually get cranky and low blood sugar if I go too long without food (I thought.) I know eat a healthy meal at 6pm, snack until 10pm and get up and drink coffee (if I crave it) and I drink water. I also workout for 1.5 hours lifting weights and 40 minutes of cardio or HIIT for 20 minutes. I may drink a ZERO CALORIE Red Bull on my way to gym on certain days. I still don’t feel much like eating at 2pm but I will have egg whites (no sugar for 2 hours after) and I actually look forward to dinner at 6pm with my family. I have plenty of energy and time to cook up a nice feast. I even have dessert if I want it. If I can do it anybody can since I use to feel hypoglycemic without food within 3 hours.NOTE: My 22 year old daughter is a Type 1 Diabetic so I always have food for her and I never encourage her to Following my fast. It does help to sleep in but many people have to get up early for work or children. The first book I read was The 8 Hour Diet. I doubt I ever do a 24 hours or more fast. 16 is just right for my age (45 female) and lifestyle. I don’t fast when I start my period and resume after it ends. I didnt discover I got a headache if I didnt watch within 2 hours upon waking. Just listen to your body. Everyone is different and you know your body better than anyone. My whole life, Ihave always dreaded breakfast. I’d rather eat if at 6pm.

  16. I generally skip breakfast and eat at 1pm ANYway..even before I knew about IF. I say listen to your body. If you’re hungry: eat. simple as that. If you want to follow IF and you know you love eating 50 times a day..dnt expect it to be easy. For me it comes more natural. i just listen to my body. I don’t starve it.

  17. Intermittent Fasting has been a miracle for me at times. Only months back did I really give intermittent Fasting any thought, at a time when my eating spiraled out of control. I was developing builimia and every time I ate, it felt like a test. Then, I started fasting and found that, compared to the 5-6 meal per day method, it kept me focused on things apart from food. I felt satisfied at meals and I didn’t uncontrollably binge on white bread and sweets. I easily ate large but balanced meals. Some days I don’t do it, and I am easily able to remain in control of my eating (although, sometimes I get in the “rhythm” of IF).
    You do make good points, but if anyone feels out of control of their eating, IF for one or more days can help you regain power over food.
    And I promise the IF gods aren’t making me type this, haha!

    1. No worries! If it works for you that’s great. My only point really is that it’s not a miracle diet tool and you shouldn’t feel bad if doesn’t work for you. Our bodies are all different and respond differently to nutritional plans and approaches to eating. I’ve been thinking about food and me as an experiment, seeing what feels good and what doesn’t. I do get frustrated though when research that’s been done on young men is then handed out as advice to women of all ages. No surprise if the fit isn’t perfect. Again, there are women who love it and men who don’t….

  18. I’ve been doing IF for about a year, I lost about ten kilos which reduced my breast size down to the point I was able to stand up straight! I really like it. In part because it helped me understand my relationship with hunger. It also made me aware of how often other women insisted socially I eat cake, biscuits etc when I really didn’t want to. Busy at work, I’ve baked a cake for the team, stressed at work let’s go out for lunch etc. I can see the pitfalls with IF, but for me it’s literally just given me space to understand my relationship with hunger, emotion and food.

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