A Bad Combination for Women: Intermittent Fasting & Paleo

By: Dave Asprey

If you’re one of the many women who read The Bulletproof Executive, this post is written for, and dedicated to you. Many thanks to Stefani Ruper of for writing an awesome review of research on Intermittent Fasting results for women. It is awesome reading for anyone who thinks that men and women respond the same way to diets.

People sometimes forget that in addition to being The Bulletproof Executive, I’m the author of The Better Baby Book. This book details the program I put together with my wife, Dr. Lana, so we could have healthy kids with better genes and healthier brains, even though she was over 40 and had previously been diagnosed with polycystic ovary syndrome (PCOS). The book is about how to use nutrition (paleo-friendly, but not paleo-derived) principles and epigenetics (the study of how environment affects genes) to enhance female fertility and pregnancy health.

I did this for my own family, and eventually we compiled 1300 references for the book that was underway for several years and is now published. It is one of my most valued achievements because I believe it will help to improve the lives of the children of every woman who reads it. It’s the instruction manual on “How to Expect More When You’re Expecting.”

But for women who are already mothers, or who are looking forward to children, or women who simply haven’t decided one way or another, fertility and women’s hormones are vitally important. Stefani Ruper’s “Paleo for Women” list of principles is worth repeating here, because she does a better job of describing what a “Bulletproof” evolutionary perspective does for women than I do:

  • With an evolutionary perspective, a woman does not work against but instead works with her body.
  • With an evolutionary perspective, a woman listens to her body.
  • With an evolutionary perspective, a woman does not see herself as separate from her body.
  • With an evolutionary perspective, a woman loves and respects her body.
  • With an evolutionary perspective, a woman is free.
  • With an evolutionary perspective, a woman feels good.  
  • With an evolutionary perspective, a woman looks amazing and real. 
  • With an evolutionary perspective, chins come up.
  • With an evolutionary perspective, a woman is fierce.
  • With an evolutionary perspective, things aren’t perfect.

I’m so pleased that Bulletproof principles have helped the women in my life feel good, look amazing, and be fierce. That’s sexy, life-affirming, and so much more interesting than “Desperate Housewives.” That’s also why we have women like Emily Deans and Ashley Tudor as guests on Bulletproof Executive Radio. High performance is not just for men. It’s also for the woman my 5-year-old daughter will become.

More than a few women have found BPE after trying Paleo and Intermittent Fasting and running into health problems after a few months. Many have found further success here, and I believe Stefani’s epic post just explained why. As she writes:

Many women find that with intermittent fasting comes sleeplessness, anxiety, and irregular periods, among a myriad of other symptoms hormone dysregulations.

This matches what I see – low calories lead to low energy, stress, and hormone dysregulation in both men and women, but it happens faster in women. That’s one of the reasons I don’t believe in caloric restriction as a generally healthy practice. In both women and men, caloric (or fat) restriction sends epigenetic signals that reduce fertility. In essence, fasting or low fat sends the message “Argh, a famine! Lack of food! Don’t reproduce!”

In men, it’s an evolutionary matter of convenience. If you reproduce during a famine, it’s uncomfortable, yes. But you don’t carry the baby around. If you’re a woman and you get pregnant during a famine, you have a much larger chance of dying when you’re pregnant or nursing because of the incredible stress it puts on your body. Low calories signals famine so a woman’s body gets stressed and stops being fertile until food supplies return to levels that can support reproduction.

Epigenetics is also the reason I don’t advocate “chronic cardio” or intense daily exercise for men or women. It sends the epigenetic signal, “A tiger is chasing you every single day. Your species must be under threat.” For men, this translates to, “Reproduce quickly and die.” For women, this translates to “Be fertile quickly (early puberty), reproduce quickly, and get out of the way (die) to make room (maybe to feed the tiger?).”

So the problems of caloric restriction, excess cardio, and intermittent fasting are related and express themselves in exhaustion, adrenal fatigue, and hormone problems, in both women and men, but women are more sensitive to these effects than men and feel the problems first.

Stefani also points out that MDA does a good job reviewing the health benefits of fasting  but that the sex-specific aspects of the hormonal response are unmentioned, and reproduction/fertility/menstrual health wasn’t mentioned at all.  She also writes:

Mark is attentive to who should and who should not be fasting.  He knows very well and cautions people against the dangers of fasting while stressed.  Still, the mere fact of being more sensitive to the strains of fasting simply by being a woman is, I would assert, pretty important for a woman who is contemplating or already practicing IF.  This goes nearly unmentioned in the blogosphere.

Amen Stefani.

Enter Bulletproof Intermittent Fasting. I used biohacking principles to make BP-IF easier on the body than “traditional” intermittent fasting, for the simple fact that it’s wasteful to apply more stress to the body than is needed to cause a hormetic change. I wanted to stay lean and muscular but didn’t have time to sleep 8 hours a night. I needed my stress hormones to do other things, so I created BP-IF.

BP-IF represents a simple way for women (and men)  to realize the benefits of IF without the risks to their health. Instead of going 18 hours without food, you have Bulletproof Coffee in the morning, which is low toxin coffee that doesn’t cause adrenal stress the way most coffee does, blended with a nice big hunk of grass-fed butter and Upgraded XCT oil in it for breakfast with no carbs or protein. It tastes great.

The fat makes your body stay in ketosis so your physiology gets the benefits of Intermittent Fasting, but the fats provide enough fuel for your brain that you don’t get the same stress response. You still have energy (it feels like more energy than a normal breakfast provides), and you can still make hormones. You don’t even want to eat lunch when you have Bulletproof Coffee for breakfast.

Bulletproof Intermittent Fasting basically tells a woman’s body that it’s time for autophagy (cellular cleanup) and rapid fat loss (ketosis), but it preserves adrenal function more than normal IF. Since you’re actually using adrenal hormones (catecholamines) to burn fat, this *really matters* more for women.

Bulletproof Intermittent Fasting also doesn’t send the epigenetic signal that you’re in a famine and should shut down your fertility. In contrast, it sends the signal, “You are in a land of plenty, with an environment full of the types of fat that make for optimally healthy babies. Be fertile! Have babies!” If you don’t believe this is real, make “Get Some” Ice Cream and feed it to a woman friend (or to yourself!) to see the effect in real life.

Does Bulletproof Intermittent Fasting work better for women? Yes. One woman just lost 28 lbs in 28 days on Bulletproof Intermittent Fasting and told me about it this morning. Even the Rapid Fat Loss Protocol works better for women than severe caloric restriction, for the same reasons that BP-IF works, although I don’t recommend the rapid fat loss program for people who have time to do normal BP-IF.

These programs work better for men too. Several have reported that they broke through weight loss plateaus using Bulletproof Intermittent Fasting that plain Leangains or MDA-style IF couldn’t touch.

On top of that, the cold hands, brain fog, irritability and tiredness that come in the afternoon with traditional Intermittent Fasting don’t exist with Bulletproof IF. Our bodies were made to use fat for fuel – if there’s enough fat, we do well, and our hormones work, and we can still lose weight.

All forms of fasting, long term, intermittent, and Bulletproof, rely on catecholamines to melt fat. If you are psychologically stressed, physiologically stressed, lacking sleep, or you have adrenal dysfunction, you need to fix that before you try any fasting protocol. Higher fat intake combined with more pink Himalayan salt can do wonders for adrenal function.

There is a reason that stressed women crave fatty and salty foods – adrenal exhaustion. Listening to your body, then eating something soaked in butter and coated with salt is not just a good idea, it’s vital to your health. It will help you be a fierce, amazing woman who feels and looks good. And it will help you to safely practice Bulletproof Intermittent Fasting without harming your adrenals, your fertility, or your brain.

Now that’s truly Bulletproof, and it works for women and men.