Intermittent Fasting - Part 3
Intermittent Fasting For Women
Research and anecdotal accounts are showing that women and men react VERY differently to Intermittent Fasting. VERY differently.
Most of the articles, books, etc that talk about all of the amazing benefits of IF are referencing research done on men, and the few studies done on women show that women may have an opposite reaction.
For men, IF seems to lower insulin levels and inflammation, but in women, it may not affect insulin levels at all. In men, it can trigger a minor adrenaline rush but in women, it can trigger a much bigger stress reaction.
Why? It seems it’s because of our fertility.
Human women are one of the very few mammals that can’t pause or terminate a pregnancy at will. For most mammals, if there’s a change in environment or food intake, their body can pause or end a pregnancy until the situation changes. Humans can’t do that, so a woman’s body is always being VERY careful to not get pregnant unless the conditions are PERFECT.
This means that if there is suddenly a lack of food, a women’s body will change the hormone balance to make sure a pregnancy can’t happen. This means that IF can cause MAJOR hormone disruptions in women. Like, IF can cause irregular periods and for some, can drop your hormones to menopausal levels and may cause cystic acne for others.
This is especially true if a woman is using IF to lose just a handful of pounds. If your body feels like you’re a perfectly healthy weight, but YOU’D like to be a bit leaner and try IF, your body may go into panic mode.
Some women report serious problems, including binge eating, metabolic disruption, lost menstrual periods, and early-onset menopause (including women in their 20s).
There’s more on why this affects your fertility below :)
The PCOS exception
Polycystic Ovarian Syndrome is a particularly tricky condition to treat both medically and nutritionally. It’s common for a woman with PCOS to have high insulin levels and high testosterone, both of which cause a whole host of problems (weight gain, facial hair, etc). Early reports find that IF may be beneficial at reducing these hormones with PCOS.
Intermittent Fasting for Post-Menopausal Women
Your hormone balance now very stable and doesn’t shift throughout the month. And, your body is no longer worried about pregnancy, so I’ve noticed (and research has found) that IF may be beneficial for you. Be sure to read the “IF for Men” section as well.
Intermittent Fasting if you have 50+ pounds to lose
Research is finding that the body will trigger a smaller stress response during fasting if there’s enough excess energy stored in your body. So, this could be something to try (while being very careful at noticing how you feel and how your body likes this method).
But…I REALLY want to try this!
At the end of this section, I’m going to list some types of IF that are very good for everyone, as well as the gentler forms of IF that can be helpful for post-menopausal women and those with at least 50 lbs of excess weight you’d like to release.
Before I get there, I’d like to share with you how this can negatively affect your body as a woman. My intention isn’t to scare you or stress you out about this, but to share the generally unspoken consequences of IF in women.
Overview of the Research on Intermittent Fasting and Women
I think it’s really important to know both the positives and negatives re: IF before trying anything. I’ve read entire books on IF, written by doctors who practice these techniques, who didn’t even mention any downsides or possible negative consequences to IF. This was SO frustrating!
A quick google search found countless accounts of female nutritional experts who’ve tried IF and had severe negative reactions. They’ve also collated all of the research showing that women’s reactions are very different from men’s (which the books didn’t talk about). Most of these women were looking to drop their body fat % below 20% to become leaner. It seems men can use IF to do this, but this is not the case for women. .
Most of these reactions are in menstruating women who are within a “healthy weight” range. Post-menopausal women, because of your stable non-fertile hormones, may react positively to IF.
In women:
IF can trigger a stress reaction in the body
IF can affect your mood, increasing anxiety and/or depression
IF can cause binge eating
IF can decrease glucose tolerance (raising blood sugar)
IF can cause insomnia
IF can slow your metabolism
IF can affect your hormones
Frankly, women may have an opposite reaction to IF compared to men (who have faster metabolisms, better mood, and lower insulin levels).
Intermittent Fasting can trigger a stress reaction in the body
Many experts, including Dr. Fung (an M.D. and prominent author on IF), talk about the adrenaline boost you get during fasting as a good thing. And, in some ways, it is.
Many people feel clear-headed and full of energy on their fast days. This is great! …unless this stress reaction is adding to a chronic stress problem.
What I find frustrating with Dr. Fung and many other IF experts, is that they don’t look at how this might affect someone who is already totally stressed out or in burnout.
This might be the straw that breaks the camel’s back in the body – the thing that tips the body over the edge and into adrenal fatigue.
Early research is finding that women’s bodies have a larger stress reaction during fasting compared to men. Please keep this in mind and evaluate the overall stress in your life BEFORE trying an IF regime.
First - Take this quiz and I recommend avoiding IF if you score over 20.
Stop Intermittent Fasting immediately if:
your menstrual cycle stops or becomes irregular
you have problems falling asleep or staying asleep
your hair starts falling out more than usual
you start to develop dry skin or acne
you’re noticing you don’t recover from workouts as easily
your heart starts beating in a weird way
your libido goes down
your digestion slows down
you always seem to feel cold
your injuries are slow to heal or you get every bug going around
your tolerance to stress decreases
your moods start swinging
Why Intermittent Fasting affects the menstrual cycle
The conversation between your hypothalamus and pituitary gland needs to be very precise for ovulation to work properly, and this conversation can be thrown off by any change in energy input.
A low carb diet alone can reduce fertility and throw estrogen and progesterone out of whack. IF can as well…so I don’t recommend combining them. Or, if you do, be VERY careful and listen to your body and cravings.
Your body is always making sure you have the resources to have a successful pregnancy, so it makes sense that being underweight or under-eating would affect your fertility so much.
On the other head, menopausal women are no longer fertile and I’ve found that menopausal women do fairly well with IF. After menopause, your hormones are lower and much more stable than during your fertile years and are no longer affected by fasting (or, much much less affected by fasting)
These are the main reasons why IF affects menstruating women so much differently than men:
1. Women are more sensitive to nutrient & energy changes than men (because of fertility)
2. Eating less protein & carbs affects hormone balance in women.
Low estrogen = Lots of imbalances
For some, IF can drop estrogen and progesterone dramatically. Yes, you’ll feel this drop inside your monthly cycle, but estrogen affects a lot more than just fertility in your body.
You have estrogen receptors all over your body, including your brain, GI tract, and bones. When you change your estrogen level your overall metabolism changes (post-menopausal women can attest to this!)
When your metabolism goes down, so does your: mood, cognition, digestion, recovery, bone health, appetite-suppression, and energy balance.
Once again, post-menopausal women can attest to this!
In a nutshell – this drop in estrogen can make you feel tired, foggy, AND hungry. It can make you want to eat A LOT more than you normally would. And…low estrogen can make your body store fat a lot easier.
Kinda the opposite thing you want from IF, am I right?
So, it’s complicated. Especially for menstruating women.
And, if you’re already under a lot of stress, don’t add this unnecessary stress to the body. Just don’t.
Intermittent Fasting & menstrual cycle
If you’d like to try out IF and you’re menstruating:
1. Start slow and conservative, ie. a short fasting window (12 – 14 hours)
2. Listen to your body and hunger signals, don’t push too far
3. Notice if your reaction is different at different points in your cycle (some IF proponents recommend a longer fasting window day 1 – 14, and a shorter fasting window day 15 – 28)
4. Try stretching the time between meals instead of full-on fasting. Can you go from breakfast to lunch? Lunch to a 4 – 5pm snack? Or, try pushing breakfast a bit later to open up your overnight fasting window.
5. Watch for any change in how you manage stress in your day. If you feel more reactive…stop IF. More anxious…stop IF. Happy & balanced…you can keep going.
Keep an eye out for any signs of disordered eating, including feeling guilty for wanting to break the fast early. And, stay open and curious to what your body is telling you <3.
Best Types of Intermittent Fasting for Women
Good for everyone: 12 – 14 hour overnight fast
Early research is showing that our insulin response to food goes up at night, and this technique is an easy way to curb evening eating. It also gives your body a nice digestive rest, which also helps with our natural overnight detox cycle. Check out the “Eating Window” section for more.
Possibly good for menstruating women – a gentle 5:2 method
This is something to try if you feel like your body would benefit from fasting. This method allows you to eat every day, so it shouldn’t trigger the hormonal problems that can come from skipping meals. Be gentle and start slow, with only 1 fast day per week. Only increase if you feel REALLY good…and adjust/cut down your fasting in the second half of your cycle.
Helpful for Many Menopausal Women – 5:2 method
I’ve heard from MANY menopausal women who’ve found success with the 5:2 method of IF. This is most effective when you’re already eating in a way that’s healthy and balanced, but you’ve got some weight you’d like to release.
It’s a good match for you if: you’re menopausal & you enjoy your fasting days. This is a good sign your body is enjoying the digestive rest <3
Be Wary or Avoid – longer fasts or short eating windows
I think we know by now that what works for men doesn’t work for women, and this is definitely the case with longer fasts or short eating windows. I’m referring to longer fasts that are 24 hours+ or eating windows 6 hours or less (or an 18 hour overnight fast).
Lisa’s “Rules” for Intermittent Fasting & Women -
If you’d like to try it, please keep these items in mind:
Listen to your body. Your body may really like this way of eating or it might not. Don’t “power through” feelings of hunger because you’re really powering over your body’s cues.
If you’re really hungry, eat. Even if you’re in a fasting window. It’s okay to ignore small twinges of hunger, never ignore HUNGER. And no, a cup of coffee doesn’t suffice. It will just bump up your cortisol level to diminish your hunger (for women, this isn’t good).
Your body’s enjoyment of IF may change at different parts of your cycle. LISTEN! And adjust :)
If you feel RAVENOUS, this might mean you didn’t eat enough the day before. Take a look at what happened (did you exercise a lot, have a large fasting window, etc) and eat something. Look at your ravenous state as sign of imbalance. Pushing through this feeling can trigger hormone and leptin issues (which will continue those ravenous feelings)
And listen listen listen to your body. Use your body as a guide, it knows EXACTLY what’s best for you.
❤️
In conclusion (and a bit of a rant that you can skip) –
Honestly, I’m really frustrated with the IF community and IF experts (you may have noticed that already…:). The medical bias on the research on IF is horrible. Few studies have looked at women, and NO studies have looked at the effects on IF and fertility. But, they continue to say how great it is for everyone.
In The Complete Guide to Fasting by Dr. Jason Fung, MD he refers to women-specifically ONCE. He writes (I’m paraphrasing, let me know if you’d like the actual page number) that he’s been asked if it’s okay for women to fast and that he sees no reason why they shouldn’t and he’s had a lot of successful women in his practice.
NOWHERE does he mention that the research is mostly on men and nowhere does he mention how it’s affected the fertility of the women fasting in his practice. (His practice seems to be mostly Type II Diabetic patients with significant excess weight) ARG!
After reading his book I was excited to try out IF myself! I wanted to see all of the great benefits he talks about! Lower inflammation, lower insulin, a happier body. He got me really excited!
But, before I did that, I wanted to look at the women-specific research, and that’s when my excitement left and my frustration came in. I’m sure you’ve felt my frustration while reading this section
So, in a nutshell, as a woman, it’s best to be cautious before trying IF, especially if you have a menstrual cycle. Start slowly and listen to your body. If it likes it, keep it up. If you get any symptoms listed above, then slow down or take a break.
This isn’t the only option, research has found similar benefits to eating nutrient-dense food regularly…so it’s 100% a-okay if this doesn’t feel good to you or if you’d rather not even try.
Be kind to your body and give it lots of love. It will always show you what it likes <3.
If you have any questions, jump to our private Facebook Group or the Ask Lisa page :)
Now it’s time to learn about the different types of IF! Head over to Part 4.