Intermittent Fasting for Women

Author: Nadine Sookhoo, BSc., MSED, RAQA

Every year we are bombarded by new trends and fads in the dieting and fitness world.  It’s important to remember that what works for one person may not work for another. In fact, many of the dieting and fitness fads out there have been designed and tested on men with very little scientific evidence as to how they work in and for women.  It’s important to try different diets and fitness regimens and see which ones work for you.

While there is a plethora of diets out there, one that is hot right now is intermittent fasting (IF). Celebrities, athletes and people from all walks of life have hailed the health benefits of this diet or rather way of eating.  However, due largely to a difference in hormones, women can respond to this diet very differently than men. This article will outline the pros and cons, the differences between men and women on intermittent fasting and also suggest some alternatives or tweaks a gal can make.  

Here is an overview of the Pros and Cons of Intermittent Fasting for women:

Let’s elaborate on some of the PROS:

• 1. Weight loss, decreased insulin resistance and reduced risk of diabetes:

So, these are a three in one, but of course, the main reason people try IF is to lose weight.  Some studies show that participants wind up with roughly the same weight as participants who weren’t on the diet, while other studies claim massive weight reduction.  Yet others cite that participants gained weight because the severe restrictions caused participants to end up bingeing and consuming more calories than they normally would. Therefore, weight loss really depends on the individual.    

One effect with evidence, is that IF does decrease insulin levels and thereby had a positive effect on people with diabetes or who were pre-diabetic.  

• 2. Lower glucose and triglycerides:

Fasting will force your body to use up glycogen, which are stores of glucose in your liver.  Then your body has no choice but to resort to burning your fat for fuel, hence where weight loss can be achieved.  Some studies have claimed to demonstrate a decrease in bad LDL cholesterol and increased good HDL cholesterol in participants undergoing IF.

• 3. Normalizes leptin and ghrelin which govern fat metabolism and hunger:

Another touted benefit has been the regulation of the complex system of hormones that regulate appetite and metabolism.  Constant insulin spikes associated with normal Western eating, that is eating every few hours, has shown to cause constantly elevated insulin levels. Therefore, the body is always secreting leptin and ghrelin, which moderate appetite.  IF does the opposite of that and helps keep insulin levels down and therefore regulating leptin, ghrelin and other metabolic hormones in your favour.

• 4. Raising human growth hormone (HGH) levels:

Chances are you may not have heard about HGH, but it has been suspected that many celebrities, especially the ones that are over forty and look like they’re in their twenties, use HGH to keep that youthful glow.  HGH has been associated with fat burning and anti-aging. Until injections of HGH become available from your dermatologist, IF claims to increase the production of this hormone substantially. One spout in the fountain of youth?  Quite possibly.

Now let’s elaborate on some of the CONS:

• 1.  There is the potential to develop fertility and hormonal imbalances:

One of the main concerns of IF has been hormonal and fertility changes. Many women have reported reproductive side effects to IF.  Now, female reproduction is vastly more complicated than men’s. We have a lot more fluctuating hormones. Essentially, if a woman’s body experiences a drastic reduction in food and nutrition, her brain will secrete hormones that will act on her ovaries and tell them to slow down production of reproductive hormones.  It’s an evolutionary response. Think about it, if a woman is halving or decreasing her amount of calories by 75%, her body will not be in optimal shape to nourish a fetus or carry to term a healthy baby. Therefore, IF is not recommended to women who are trying to conceive, are pregnant or are breastfeeding.

The monthly hormonal fluctuations of the female menstrual cycle

We have so many hormones that are changing throughout our cycle, it makes things complicated!

• 2. There is the potential to develop adrenal fatigue or exhaustion:   

This one is easier to explain.  Essentially your adrenal glands, situated on top of each of your kidneys, also plays a role in sugar/insulin levels in the blood thereby regulating energy levels.  When you skew the amount of sugar and insulin in your blood on IF there is the potential for your adrenal glands to work overtime to regulate your blood sugar levels resulting in adrenal fatigue or exhaust.  

• 3.  IF can cause changes in thyroid function:

IF has been shown to decrease T3, which is one of the thyroid hormones.  However, it did not affect T4 or Thyroid Stimulating Hormone (TSH) levels. Together T3 and T4, regulate your body’s temperature, metabolism, and heart rate. One test to see if your thyroid is being affected negatively on IF is to observe if you are cold most of the time.  This is an indication that your thyroid levels could be off. Consequently, women who suffer from hypo or hyperthyroidism should consult their specialists before going on IF.

• The main differences between men and women on Intermittent Fasting:

It has been hypothesized that women are more sensitive to hunger hormones than men. We’ve learned that leptin and ghrelin are hormones that regulate our appetites.  Men and women both produce a reproductive hormone called kisspeptin. It turns out that women produce more kisspeptin and this makes them more sensitive to the hunger hormones.  This results in women experiencing more pronounced side effects from fasting, more so than men. It also results in women experiencing more ‘hangriness” than men. However, I would argue that some people are just better at bearing hunger than others and I do believe people can gradually acclimatize to it.

• Tips for Women:
• See your family doctor first
• Try paleo or keto diets first
• Try Crescendo Fasting if you find IF is too intense
• Ease into it, that is allowing yourself to acclimate. Don’t go “cold turkey”
• Keep track of your progress, mood, sleep, menstrual cycle
• Women who have been diagnosed with an eating disorder should not attempt IF, unless under the supervision of a doctor

Good luck and happy fasting!

References

Boelen A., Fliers E., Wiersinga WM. Fasting-Induced Changes in the Hypothalamus–Pituitary–Thyroid Axis. Thyroid 2008 2: 45-53

https://www.ncbi.nlm.nih.gov/pubmed/18225975

Castellano JM., Handlesman DJ., Navarro VM., Pinilla L,. Roa J., Tena-Sempere M. Kisspeptins
and the control of gonadotropin secretion in male and female rodents. Peptides 2009 1: 57-66
https://www.sciencedirect.com/science/article/abs/pii/S0196978108003550