Some Think Intermittent Fasting Is Bad For Women. Here's Why

Integrative Medicine Doctor By Amy Shah, M.D.
Integrative Medicine Doctor
Dr. Amy Shah is a double board certified MD with training from Cornell, Columbia and Harvard Universities. She was named one of mindbodygreen's Top 100 Women In Wellness to Watch in 2015 and has been a guest on many national and local media shows.
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Unless you've been living completely off the grid for the last few years, you've probably heard a thing or two about intermittent fasting. Understandably, many people are wondering if it's really the panacea that everyone seems to think it is. Does intermittent fasting affect men and women the same way? If you have hormone dysfunction, is it still safe?

These are all questions I field every day, and my patients are right to ask these questions, especially when it comes to intermittent fasting and women's health. Women are biologically different from men, especially when it comes to hormone health. It's more common for a woman to get stress-related alternations in hormone health that affect hunger, metabolism, and reproduction—which could potentially interfere with the benefits of intermittent fasting.

Why some women should avoid fasting.

Right off the bat I'll say that no one knows for sure whether intermittent fasting can contribute to hormonal dysfunction. But I, like many doctors, have formed an opinion based on my personal experience, clinical observations, and the research that does exist. My opinion is that intermittent fasting can be done safely for most women—if done carefully and with the guidance of a practitioner.

Here's who should not attempt fasting on their own:

1. Pregnant or breastfeeding women

2. Underweight women with a BMI of 18 or under

3. Women with a history of an eating disorder

4. Anyone with major medical issues like diabetes or hypertension

This doesn't mean that if you fall into one of these categories you can't experiment with IF at all; it just needs to be done under the supervision of a medical doctor.


The truth about IF and hormone balance.

If you don't fall into one of these categories, IF is most likely safe for you to experiment with. That said, you may have heard chatter that IF might be to too stressful for female hormones and that it can exacerbate imbalances. Is this true?

Women are quite sensitive to starvation. For example, when women get under a certain body fat level, they may stop ovulating. If you're putting yourself in starvation mode on a regular basis with IF, could your hormones respond in a similar way? According to a few animal studies, it's a possibility. After two weeks of IF, female rats stopped having menstrual cycles and their ovaries shrunk, and male rats ended up with lower testosterone production. Insomnia was also more common among female rats.

This doesn't mean the same is true in humans, but unfortunately, there haven't been very many studies published looking at the effects of IF on women's hormone health. All we can assume is that there's a chance that fasting will throw off a woman's hormone balance and cause fertility problems.

If you're experimenting with IF and are concerned about hormonal imbalance, here are some signs to look out for:

  • Fatigue
  • Bloating
  • Depressed mood
  • Irregular periods
  • Headaches

How to protect your hormones if you want to try IF.

In my practice, I don't find that intermittent fasting and hormone imbalance is a huge issue. There are thousands of women fasting with no hormonal issues at all. I tend to notice that this problem happens more for women who are extending their fast beyond 24 hours and fasting very often or women who have very low body fat to begin with.

So what's the bottom line? Unless you're on the list of women who should avoid fasting altogether unless your doctor approves it, it's definitely worth a try. The key is to check into your body when you start fasting. Monitor your energy, your menstrual cycle, and your hunger and cravings to know if you're on the right track. Start with just 12 hours of intermittent fasting two days a week, then increase to 14 or 15.

If you're concerned about hormonal imbalance, it's a great idea to work with a practitioner, like an integrative or functional medicine doctor or naturopathic doctor, that is familiar with fasting protocols and approaching women's hormone health from a holistic perspective.

Amy Shah, M.D.
Amy Shah, M.D.
Dr. Amy Shah is a double board certified MD with training from Cornell, Columbia and Harvard...
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Amy Shah, M.D.
Amy Shah, M.D.
Dr. Amy Shah is a double board certified MD with training from...
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