Dear Mark: More On Women and Fasting

Dear_Mark_Inline_PhotoLast week, I updated an older post on women and intermittent fasting. For today’s edition of Dear Mark, I’ll be answering some of the comments and questions from that post. First, should a lean woman with a stressful life try fasting to heal her gut? Maybe, maybe not. Second, does coffee break a fast? Now, where have I heard that one…? Is a 12-hour fast a good starting point for women? What are the IF “pre-reqs”? And finally, what do we make of women who can fast successfully? Does habituation have an effect?

Let’s go:

Megan asked:

I am a 33 yo woman. I am 5’9 and between 129-133 lbs. My longest fasts have been 4 days and we’re medically indicated (i.e. I was hospitalized and not allowed to eat) due to painful flares in my Crohn’s/ileitis (I have recently switched to all meat as my worst flare left me in the worst pain of my life and was from eating veggies/fiber). I naturally do some amount of intermittent fasting (16 to 20 hours).

I am interested in longer fasting than what I do for its potential to help heal my gut, but a several things stop me. 1. I become voracious by about hour 21. I can’t seem to push through. And I have been keto-adapted since August 2017. 2. Though my BMI is in “normal” and I have good muscles, I am on the lean side. 3. Life is kinda intense this year. Yeah, yeah, I meditate and all that. But life has been very intense.

Does anyone have any thoughts on extended IF for gut healing for a lean, probably too stressed, woman?

Check with your doc first. It’s worth a try.

In one study, patients with irritable bowel syndrome (IBS) were fasted for 10 days after four weeks of regular IBS treatment. Another group continued the regular treatment. The fasting group saw improvements in 7 of 10 markers, including abdominal pain, abdominal distension, diarrhea, anorexia, nausea, anxiety, and general interference with life.

Crohn’s isn’t the same as IBS. Crohn’s is generally more serious and can result in physical damage to the gut. But the symptoms are similar enough that this fasting study piques my curiosity.

Improving gut health and reducing inflammation doesn’t require full-out fasting, though.

In obese women, severe calorie restriction (800 calories per day) reduced overall inflammation and improved gut barrier function. They also had a lot of weight to lose, and they lost an average of 15 pounds over 4 weeks. That’s quite good for a short study. It’s hard to know whether it’s the calorie restriction or the weight loss improving the gut health.

Side note: a really cool part of this study is that 14 days after the very low calorie diet, when they were back to their regular diets, the women had gained about half a pound back, but it was lean mass. They actually lost more body fat and had a smaller waist circumference than they did after the 14 day low calorie diet.

My point is that calorie restriction was good enough.

Fasting may very well work for you, but it might not be necessary. It might even be too much of a good thing, given your stress levels. Try it—that IBS study is pretty convincing—and be aware.

Micki asked:

Question: I’ve heard both, that black coffee breaks your fast and that black coffee doesn’t break your fast. Opinions? Evidence to either?

Check out my recent post on the subject. It should answer your question.

Micki wrote again:

I’ve reached the point of not trying to force any specific IF protocol other than a regular 12 hour fast every day, which is usually 8pm-8am.. If I go longer, I go longer but I have ceased shooting for any other IF time period. This is what suits me but may not suit anyone else that tries IF. We’re all different, eh?

For what it’s worth, my experience talking with dozens of women is that 12 hours is a sweet spot. Anyone (especially women) curious about fasting should start there, see what happens.

Stacey Martin asked:

Where would we find the IF pre-reqs?

It’s there in the article:

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.

Fat-Adapted: You should have your fat-burning machinery up and running, as fasting places great demands on your ability to burn your own body fat for energy.

Stress: Fasting can be stressful, so don’t add it to an already-stressful life. Stress adds up, whatever the source.

Sleep: Poor sleep makes dieting less effective. It also makes you hungrier, especially for junk food.

Exercise: Too much exercise and you’ll make the fast more stressful than is helpful and hamper recovery. Too little exercise and, well, I don’t have any objective reasons. I just know that exercise and fasting go perfectly together. There’s nothing more delicious and satisfying than a meal after a fasted training session.

blah wrote:

I’m a woman, have been skipping dinners for over 5 years, going 12-16 hours with no food daily. I still consume around 2000 cal a day and weigh about 130 lb. My cycles seem to get less regular the more I deviate from this routine and gain weight.

Also if fasting was hurting fertility how do we explain India and other 3rd world countries?

The key here may be your consistency. This conditions your body to expect food (and get hungry at the right time, not before), and it improves the metabolic response to eating.

In one study, the authors actually tested the effect of breaking your eating habits by separating overweight women into habitual breakfast skippers and habitual breakfast eaters and then having them either skip breakfast or eat breakfast.

Habitual breakfast eaters who skipped breakfast experienced way more hunger at lunch, had worse blood lipids, and higher insulin levels. They had worse blood lipids and their insulin skyrocketed. Habitual breakfast skippers who skipped breakfast experienced none of these deleterious effects.

Meanwhile, habitual breakfast eaters who ate breakfast were more satiated at lunch. They had better blood lipids and normal insulin levels. Habitual breakfast skippers who ate breakfast were still hungry at lunch. Eating breakfast didn’t inhibit their regular lunch-time appetites.

Other research has found that maintaining a regular eating schedule improves insulin sensitivity, increases energy expenditure, and improves fasting lipids. Overall, sticking to an (rough, not draconian) eating schedule results in the best metabolic effects, which appears to be what you’re doing.

That’s it for today, folks. Thanks for reading, asking, and writing. Take care!


About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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