Dr. Amy Shah on What Intermittent Fasting Really Means for Women

Dr. Amy Shah on What Intermittent Fasting Really Means for Women

Hey! Lately, there’ve been a lot of myths and misinformation about intermittent fasting. Therefore, I invited Dr. Amy Shah to share her thoughts on this.


Chances are if you are health and fitness savvy, you’ve heard of intermittent fasting and its benefits for fat loss, hormone balance and overall health.

But did you know that, if you’re a woman, fasting can feel different. It can imbalance your hormones if done improperly and actually help them if done properly.

Wait, what? I know it sounds confusing but it’s not. Read on.

What is Intermittent fasting?

An intermittent fast is a brief break from food where, for 12–16 hours or more, you don’t eat anything except water (a few exceptions apply). And while that may sound incredibly difficult to achieve, you might already be fasting without knowing it if you eat dinner at, say, 7 p.m. and break your fast in the morning between 7—10 a.m. — and if you only have water and black coffee or tea between. 

For so many of us– we have been trained to eat six times a day to “keep our metabolism going,” so it can be an arduous and seemingly contradictory feat to go 12-plus hours on water alone. But science actually backs this ancient practice.

Medical studies have shown that intermittent fasting:

  • Increases energy
  • Improves cognition, memory and clear-thinking
  • Makes us less insulin-resistant, staving off fat and insulin related disease by reducing levels of circulating IGF-1 and increasing insulin sensitivity without lowering the resting metabolism.
  • May improve immunity, lower diabetes risk, and improve heart health
  • Increases production of brain neurotropic growth factor — a protein that promotes neuron growth and protection — making us more resilient to neurological stress and thus staving off neurodegenerative diseases.

My (FAILED) Initial Fasting Experience

Knowing the potential health benefits of intermittent fasting for women, I was eager to give it a try. Unfortunately, I failed MISERABLY at my first attempt. Let’s just say I did NOT experience increased energy and clear-mindedness.

The first day I under-ate and couldn’t sleep for hunger pangs. The next day, tired and cranky, I overate with the veracity of a starved animal. That’s when my hunger and hormone roller coaster began. After one full week of this, I had to quit.

As a physician I wondered if other women had experienced something similar. And when I searched the internet, I discovered that, across message boards, blogs and online communities, women were complaining about intermittent fasting and its effect on their hormones.  The research was sparse and animal-based, but it did seem that it can either hurt or help your hormones.

The Fasting and Hormone Connection

To put it simply, intermittent fasting can cause hormonal imbalance in women if it’s done too aggressively. It seems that women are extremely sensitive to signals of starvation or stress.If you start yourself, your body will significantly increase production of the hunger hormones, leptin and ghrelin.

So when women experience insatiable hunger after under-eating, they are actually experiencing the increased production of these hormones. It’s the body’s way of protecting a potential baby — even when a woman is not pregnant. Have you ever had this feeling of hunger? If you have ever gone on a crash diet, you know that your body turns up the volume on these signals.

Many women ignore these hunger cues, causing the signals to get even louder. Or, worse, we try to ignore them, then fail and binge later, then follow that up with under-eating and starvation again. And guess what? That vicious cycle can throw your hormones out of whack and even halt ovulation. 

In animal studies, aggressive fasting, female rats stopped having menstrual cycles and their ovaries shrunk while experiencing more insomnia than their male counterparts (though the male rats did experience lower testosterone production).

But what about with PCOS? The main issue with PCOS is that the hormones are imbalanced- usually high insulin.  Now in this case, fasting is the THE BEST way to get those levels down and improve your condition.

In PCOS it is the high insulin levels that stimulate testosterone production from ovaries. So bringing down those insulin levels brings down testosterone levels as well – mitigating the symptoms of PCOS.

In addition, women with PCOS also tend to have higher cholesterol, greater inflammation and have a greater risk of cardiovascular disease. Intermittent fasting can help improve cholesterol levels, inflammation levels and therefore improve overall health in women with PCOS.

Recommended Fasting for Women

Intermittent fasting for women can be done, but women-especially with PCOS, could modify their strategy – especially if it has not worked for you before.

Remember, usually problems arise when you jump in too quickly or too aggressively. So if you are a woman or trying fasting for the first time, you might benefit from my style of intermittent fasting that I call: Circadian Gut Rest.

This requires you to fast only for 16 hours for a few days, and the others days you do just 12 hours. My experience is that women benefit more from doing it this way, without accidentally throwing their hormones into frenzy. We also use the magic of circadian sun cycles to improve our health. This is a more gentle approach that helps the body more easily adapt to fasting. And if women do it right, it can be an amazing way to shave off body fat, improve inflammatory markers and gain energy.

Here is how to do it:

  1. Fast 16 hours starting at 6 or 7 PM on 2–3 non-consecutive days per week (e.g. Tuesday, Thursday and Saturday)
  2. On fasting days, do yoga or light cardio.
  3. Ideally, fast for 16 hours.
  4. On other days, fast for 12 hours (starting before 8pm is ideal) and workout normally.
  5. Drink plenty of water. (Tea and coffee are okay too, as long as there is no added milk or sweetener)
  6. If you feel very hungry, have upto 40 calories of no-sugar food like peanut butter or avocado.
  7. Take one day off : example saturday

If you have failed at intermittent fasting before, try this style for a better, more sustainable experience.