A Complete Guide to Healthy Fasting Without Affecting Your Menstrual Cycle

Intermittent fasting is an excellent way to achieve weight loss. This strategy generally has incredible results; but if not done right, some women find that it stresses out their bodies too much and disrupts their menstrual cycles as a result. In this guide, I will discuss several topics on intermittent fasting and menstrual cycles, as well as offer suggestions on how you can start a healthy and happy fasting journey without negatively impacting your periods.

  • Intermittent Fasting and Female Hormones
  • 11-30% of Female Fasters May Experience Disruption of Their Periods
  • Do You Need to Adjust Fasting Hours in Different Phases of Your Menstrual Cycle?
  • Use Period Tracker in FastingQueens to Monitor Your Menstrual Cycle
  • What Intermittent Fasting Methods Are Suitable for Women?
  • Tips for Doing Intermittent Fasting Without Affecting Your Period

Intermittent Fasting and Female Hormones

Many of the metabolic benefits you obtain from fasting are due to your body’s response to stress.

Most of us think of stress as a bad thing. However, we forget that we need small amounts of stress in our bodies for it to react. If we know how to manage those stress levels, it can promote healthy responses in the body. The problem arises when we have too much stress in our bodies that we cannot handle.

The female reproductive system is very susceptible to stress. When dealing with too much pressure, the body pauses everything, which could cause your ovulation and menstrual cycle to stop.

Stress occurs when we have a very low caloric intake, whether for weight loss purposes or any other factor. The body doesn’t understand our intentions; it only senses a reduction in food intake. These shifts in our caloric intake can create a lot of stress in the female body.

When our caloric intake is too low (from fasting or eating too little), a part of our brain (hypothalamus) suffers.

An alteration in our hypothalamus could lead to a decrease in the secretion of gonadotropin-releasing hormone (GnRH), which directly affects the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH)—resulting in a cascade of hormonal imbalances (decreasing estrogen and progesterone).

All of these hormones are essential for fertility since they are involved in releasing a mature egg and supporting pregnancy. Ultimately, a hormonal disbalance can put you at risk of having irregular periods, decreased fertility, and poor bone health.

Not every woman will have these negative consequences from fasting. However, if you do see a change in your menstrual cycle, it’s essential to stop and do shorter or fewer days of fasting throughout the week.

11-30% of Female Fasters May Experience Disruption of Their Periods

As mentioned earlier, not every woman is going to have menstrual disturbances when practicing fasting. Currently, there is inconclusive evidence showing the effects of fasting and menstrual cycles.

On one hand, some studies have shown that for women with PCOS, fasting for 16 hours can stabilize their menstrual cycles (If you suffer from PCOS, please check out two PCOS-related articles at the bottom of this guide). On the other hand, other studies have reported a decrease in LH and FSH hormones, leading to irregular menstrual cycles. It seems that 11-30% of women who followed more extended periods of fasting had alterations in their menstrual cycles.

The link between fasting and its effect on your menstrual cycle depends on several factors. We would advise you to:

  1. Always listen to your body.
  2. Don’t fast over 14 hours per day during the week before your period. Resume your usual schedule after that.
  3. Use Period Tracker in FastingQueens to monitor your menstrual cycle. If you find your periods have been disrupted since you started fasting, relax your fasting efforts.

Use Period Tracker in FastingQueens to Monitor Your Menstrual Cycle

Note: We have a reminder to help you input your period records. Please keep track of your period every time it ends. The more accurate data we have, the better advice the app can provide for you. 

Do You Need to Adjust Fasting Hours in Different Phases of Your Menstrual Cycle?

According to Dr. Harshi Dhingra in her article Why You Shouldn’t Fast Too Hard Before Your Periods, she mentions “a female’s body is particularly vulnerable to stress in the week leading up to her period … It is suggested that you don’t fast at all, or do an easy fasting of 12 to 14 hours at most.” During this week, you may have a very normal craving for sweets. However, healthier options would be  “fruits (bananas, oranges), yogurt, smoothies, and 70% dark chocolate, etc.”

If you think you’ll struggle to remember when your period is about to start, do not worry. In FastingQueens, as long as you continue to input your menstrual cycles, we will notify you a week before your expected period. You can then adjust your fasting plan accordingly.

Intermittent Fasting Approaches We Recommend to Women

Women can be more sensitive to fasting than men are, so it’s important to start gradually. Here is our recommended schedule:

Tips For Doing Intermittent Fasting Without Affecting Your Periods

Start Slowly

The first thing we always recommend to our clients is to start with a shorter fasting window; 12 or 14 hours is a good place to start. Once you are comfortable with the shorter fast, you can increase the hours. However, do it slowly. For example, don’t jump from 12 hours to 16 hours all at once. Increase your fasting hours to 14 hours for a week and observe your body’s reaction. If daily fasting for 14 hours is too much, try the crescendo method – fast 14 hours for 3 days and fast 12 hours on the other 4 days.

Don’t Compare Yourself To Others

Everybody is different, and hormonal responses also vary. What might be good for one woman might not be for another.

If you know that your friend is doing extended fasting with positive results, it doesn’t always mean it will be suitable for you. You could end up having side effects that she didn’t have. That’s why it’s always good to start slowly and pay attention to any reaction your body has.

One Diet at a Time

It is common for women to try all the strategies at once; for example, doing keto or paleo simultaneously with intermittent fasting.

While any type of eating pattern can be adjusted to fasting, it’s better to focus on one thing at a time.

For example, get the fasting right first, and once you don’t have any problems fasting for long periods of time, you can start modifying your eating habits.

Taking it one step at a time will give you more sustainable results and prevent hormonal imbalances.

Drink Plenty Of Fluids

Water is essential to maintain optimal hydration levels in your body. Water, coffee, and tea all won’t break your fast, so you have some options when it comes to hydration. Make sure that you’re drinking enough throughout the day, especially when you’re fasting.

Focus on Food Quality

Even though the main focus of intermittent fasting is not food quality, it is still an essential aspect of a healthy life. During your eating windows, focus on natural ingredients.

One piece of advice we give my clients is to follow the 80/20 rule. It means 80% of the foods you eat should be from natural sources. The other 20% can be processed foods.

Add different colors of veggies and fruits to your diet to have a more diverse source of nutrients. Each color of fruit indicates different characteristics. That is why we always recommend eating at least 3 different colors of fruits or veggies per day.

You should also be sure to eat whole grains to provide fiber, protein to maintain muscle mass, and healthy fats to help regulate your hormones.

Increase Your Protein

One of the most common mistakes we often see clients make is not paying attention to protein. Protein is essential for muscle mass, and it slightly increases your metabolism since it takes more energy to digest than carbs and fats.

If you are going to try intermittent fasting, make sure that you have at least 3 to 4 sources of protein throughout the day. Sources like chicken, fish, meat, Greek yogurt, eggs, protein shakes, and legumes (beans, lentils, chickpeas, and edamame) are great protein options. These add necessary amino acids to your diet and keep your muscles strong.

Listen To Your Body

Finally, the most important thing is to always listen to your body. Don’t ever get to the point where you feel consistently hungry for more than 30 minutes, as mentioned in the article A Guide to Handling Hunger.

The same applies to your hormonal changes. If you start fasting for 16 hours and your menstrual cycles change, it’s better to stop and change your fasting strategy.

The Bottom Line

Fasting can provide several benefits for women. It can promote weight loss and reduce the risk of diabetes and heart disease. It can also reduce inflammation in the body. However, it might change hormone levels, reduce fertility, disrupt menstrual cycles, and cause mood swings. With careful planning and progression to longer fasting hours, you will enjoy all the health benefits with intermittent fasting without negatively impacting your periods.