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You may have heard a lot about intermittent fasting (IF) lately, but intermittent fasting has been around since the 5th century, and recently exploded in popularity within the fitness industry in 2012. Intermittent fasting is a popular lifestyle choice due to its potential benefits for weight loss, body composition, improved insulin sensitivity, disease prevention, and well-being. But for women, especially those over 40, it’s important to understand how intermittent fasting impacts your hormones (those little messengers that control your metabolism) and your overall health. So, let’s take a closer look!

First, what exactly is intermittent fasting?

Intermittent fasting is an eating pattern that includes regular, short-term periods when you don’t eat food. Unlike other diets, intermittent fasting has gained popularity by allowing you to eat whatever you want to eat, but just within a restricted time frame. It is often viewed as a lifestyle, rather than a diet. It is a simple, convenient way of eating that can help reduce body fat and allow for weight loss.

When a body is in a state of fasting, cellular repair transpires. With these relaxational periods that the body experiences there is a connection to increased endurance, decreased risk of cancer, diminished inflammation, and enhanced metabolism.

What are some of the benefits of fasting if I’m a woman over 40?

Weight Loss and Management

IF helps regulate the balance of energy in and out, aiding in weight loss and management.

Improved Metabolic Health

It can enhance insulin sensitivity, reduce inflammation, and improve various markers of health.

Enhanced Brain Health

IF is linked to improved brain health and a reduced risk of neurodegenerative diseases.


Some studies suggest that IF can extend lifespan by impacting biological processes related to aging.

Sounds like a vacation for the body, right? Maybe, maybe not. Like all diets, intermittent fasting affects everyone differently; especially women. Women’s bodies are more sensitive to fasting and dieting due to their hormones and reproductive systems, but we’ll dive into the science in a minute.

How can women gain the benefits of intermittent fasting and still support hormone health?

Simple. By breaking up the fast so that her body doesn’t go into “panic” mode. Two ways for women to reap the benefits of intermittent fasting without the side effects of hormone imbalance include the 5:2 fasting method, and the 12, 14, or 16-hour fast.

Before you consider trying one of these versions of intermittent fasting, there are a few boxes that should be checked off first.

  • Stress level is low
  • You’re getting 7 to 9 hours of sleep at night
  • You’re not afflicted by hot flashes and mood swings
  • No other nutritional deficiencies

Fasting Method #1: The 5:2 Fast

This method of fasting can be described in 2 ways: either choose 2 days per week to do a full 24-hour fast or choose 2 days per week to restrict calories to less than 500.

An example of this would be to eat normally on Sunday and have your last meal at 7 pm.  Then Monday is a fasting day, and you don’t eat anything until 7 pm that evening. Then Tuesday, Wednesday, and Thursday are normal eating days, with the last meal at 7 pm.  Friday would be another fasting day with a meal at 7 pm. Then Saturday and Sunday are normal eating days.

By using this method, the fast is broken up into 2 separate 24-hour periods each week. This allows your body to burn extra calories on those fasting days, without feeling deprived or impairing hormone levels. Many women find this method easy to follow because you can look at your schedule and plan which days will work best for your fast. It is flexible and yet still very effective.

Fasting Method #2: The 12, 14, and 16-hour fast

Another effective fasting method for women is a consistent 12, 14, or 16-hour fast. This is where you restrict your eating window to a period of eating in a 12, 10, or 8-hour window daily.

For example, you eat between the hours of 8 am and 8 pm for a 12-hour fasting period. Or eat between 8 am and 6 pm for a 14-hour fasting period. This is also a nice method because you can shift the hours forward or backward, depending on your schedule or preference. Yet you still get the benefits of regular fasting and allowing your body a period of rest from digestion.

You could even combine the 2 techniques for additional benefit! Choosing either of these methods is a great way to start out, especially if you are new to intermittent fasting. It is easy to follow and doesn’t interfere with your busy schedule.

Troubleshooting tips for a successful and safe fast

A bowl full of saladFor the first few weeks, you may feel great and even lose some weight! But if your body begins to plateau, you may want to consider other lifestyle changes to boost weight loss efforts. Something as easy as modifying what you eat for breakfast and lunch, but then allowing yourself to eat what you would like for dinner will give you a little boost! Or adding a walk into your weekly routine can also increase weight loss efforts.

Make sure to drink plenty of water throughout the day. We suggest half your body weight in ounces.

To help with daily bowel movements, taking a magnesium supplement, such as our BeRegular, at night can help with bloating and fluid retention which hides true weight loss.

During this period of fasting, you need to listen to your body. If you begin to get light-headed or feel nauseated, make sure to eat something! Each of us is different and you will quickly figure out the best methods, foods, and habits that work for your body.

And if you are restricting food and calories, you may also want to add in supplements. Your body needs vitamins and minerals to carry out everyday functions. And if they aren’t coming from your diet, it is easy to add them as a supplement to experience the full benefit of intermittent fasting.

More science behind fasting

Warning, our “scientific nerd side” is about to come out!

The hormones regulating key functions like ovulation are incredibly sensitive to your energy (food) intake. In both men and women, the hypothalamic-pituitary-gonadal (HPG) axis — the cooperative functioning of three endocrine glands — acts a bit like a symphony conductor.

First, the hypothalamus releases gonadotropin-releasing hormone (GnRH). This tells the pituitary to release luteinizing hormone (LH) and follicular stimulating hormone (FSH). LH and FSH then act on the reproductive organs. In women, this triggers the production of estrogen and progesterone — which we need to release a mature egg (ovulation) and to support a pregnancy. In men, this triggers the production of testosterone and sperm production. Because this chain of reactions happens on a very specific, regular cycle in women, GnRH pulses must be very precisely timed, or everything can “get off beat.” GnRH pulses seem to be very sensitive to environmental factors and can be thrown off by fasting. Even short-term fasting (say, three days) alters hormonal pulses in some women.

There’s even some evidence that missing a single regular meal (while of course not constituting an emergency by itself) can start to put us on alert, to prepare our bodies to quickly respond to the change in energy intake if it continues.

Nerd moment is over!

Stress and intermittent fasting

Specifically for women, stress (especially chronic stress) may be to blame for the hormonal domino effect we’ve been talking about. And it’s not JUST about how much food you eat.

Negative energy balance can result from:

  • too little food
  • poor nutrition
  • too much exercise
  • too much stress
  • illness, infection, chronic inflammation
  • too little rest and recovery

Psychological stress can absolutely play just as high of a role in damaging our hormonal equilibrium, as physical stress. Our bodies can’t tell the difference between a real threat and something imaginary generated by our thoughts and feelings.

Any type of stress produces the hormone cortisol. Cortisol inhibits our friend GnRH and suppresses the ovaries’ production of estrogen and progesterone. Meanwhile, progesterone is converted to cortisol during stress, so more cortisol means less progesterone. This leads to estrogen dominance in the HPG axis.

Fasting is different for women than men, especially as women age.

Woman does yoga pose on grassWhen it comes to fasting, women (particularly those over the age of 40) are affected differently than men. Women are more sensitive to changes in hormone levels. This is because the survival of a species relies on women carrying a full-term pregnancy and successfully giving birth. Research shows that women who get pregnant while they are starving or malnourished, have a higher risk of death during pregnancy.

Because of this, women’s bodies are created to have a greater sensitivity to changes in energy balance. Women have a quicker stress response to fasting than men do, and women have a much stronger hunger response and sensitivity to hunger hormones.

Additionally, there is evidence that women may be more prone to disruptions in blood sugar levels, which can be caused by intermittent fasting. This is due to the fact that women tend to have less muscle mass and more body fat than men, which can affect how the body processes glucose. In women, a prolonged fasting period can lead to increased anxiety, adrenal insufficiency, irregular periods, sleeplessness, and poor bone health.

Additional potential dangers of intermittent fasting:

  • Hormone dysregulation
  • Altered menstrual cycle
  • Poor eating habits
  • Loss of hunger cues
  • Increased stress hormones

Here at BeBalanced, many of our clients will come to us with hormone imbalances and weight struggles. We combine lifestyle habits with quality nutrition to help you achieve your goals. Our experts are here to walk with you each step of the way.

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