You may have heard that if you are a woman, you should avoid fasting so as not to harm your hormones. A huge part of this reasoning derives from the number of studies focusing on male subjects, thus resulting in the mass prescription of the “everyday 16-18 hour fasting cycle” or “constant alternative day fasting cycle” for everyone without much care for the specific needs of the female hormonal system. Fasting in this manner for women can cause gluconeogenesis, a cortisol-releasing process which causes your body to break down tissue and bone for fuel. Due to being taught fasting from a male perspective, there is now of fear-mongering occurring around all types of fasting for women; As a result, women are missing out on the ever-growing benefits of fasting. This article explores fasting as a strategic tool for weight loss and hormone regulation. By aligning fasting with the hormonal cycle, women can reap the benefits of fasting.

What is Fasting?

Fasting or time-restricted feeding is described as restricting one’s eating to a particular set of hours or days. If this idea sounds familiar, it is because you likely have been participating in some mode of fasting your entire life. The term "breakfast" simply means the first meal you use to “break your fast” since you would not have eaten for the several hours you spent sleeping. Even if you are the type to skip breakfast in favour of lunch, you are only extending your fast. Whether it is due to societies originally being full of hunter-gatherers or religious reasons, humans have been fasting for centuries. As Western society moved towards industrialization, the typical daily schedule had to be implemented, so the 3 meals-a-day became a huge part of our lifestyles. As time progressed, snacks like peanuts became a way for capitalism to target poor people, who might not have had time to eat a full meal due to work. While they had not known it yet, constantly stuffing their mouths with food led to humans becoming at increased risk of neurodegenerative and psychiatricdisorders. With the rise of insulin resistance and obesity, people are still snacking and eating consistently throughout the day, thus going against what humans were great at by nature: fasting.

Fasting for Weight Loss

At face value, weight loss is simple: it is calories in and calories out; However, experts are finding that insulin sensitivity, gender, and even hormones are all important factors which largely affect someone’s weight loss journey. Fasting can act as an effective strategy for weight loss due to the ease of reduction in caloric intake. Naturally, by restricting the eating window, you eat less. In working with the various factors which can affect why someone cannot lose weight, fasting can also improve metabolic markers, such as insulin sensitivity. By having an increase in insulin resistance, you get that gnawing feeling of hunger easier, causing you to want to eat more. Through fasting lowering insulin resistance, your body can focus on using stored glycogen and fat for energy. While weight loss is a great overarching goal, the emphasis should be on fat loss to better one’s overall metabolic health by retaining as much muscle as possible. Furthermore, fasting can also promote fat loss as it aids in the breakdown of stored fat for energy, thus leading to fat loss rather than the loss of muscle mass. Additionally, you can look better because muscle retention will prevent the “skinny-fat” look. In continuing with the appearance benefits of fasting, exercise combined with fasting can result in positive effects in body composition.

While you can lose weight without fasting, fasting can make it a lot easier to do so, in addition to having a variety of benefits to your appearance.

How to get started?

Mapping your fast to your cycle will allow you to receive all of these fantastic benefits without causing excess stress to your hormones. Known for her expertise in

metabolic health, Dr. Mindy Pelz has developed an innovative way to approach fasting that works with women’s fluctuating hormones called “The 30-Day Reset”.

For women with a healthy 28-30 day cycle, Dr. Pelz says the first 3 weeks of your cycle are the best times to fast. On Day 1 of your cycle, Dr. Pelz recommends that women begin fasting. These days are marked as the menstruation phase leading into the follicular phase. During the follicular phase, your hormones will rise since estrogen is building up the lining in your uterus so that you can eventually ovulate. Since estrogen thrives when insulin levels fall, Dr. Pelz suggests fasting with a minimum of a 13-hour fast window. By Day 5, Dr. Pelz recommends a minimum of a 15-hour fast window, which is longer than the first few days as your hormones continue to increase. By Days 6-10, Dr. Pelz recommends a 17-hour fast minimum, so that your body can enter autophagy. By this time, your estrogen levels will have peaked, so your body can tolerate a longer fast. For those more comfortable, Days 1-10 can also allow for a longer fasting length anywhere from 13 to 72-hour fasts to get the full effects of autophagy. By days 11-15, your body will begin to ovulate and hormones will be at their peak. Dr. Pelz recommends retreating to the previous 13-hour fasting window and eating lots of healthy fats to boost fertility health during this time. By Days 16-19 of your cycle, she recommends going back up to a longer fast from around 15 hours or more. As your cycle finishes off throughout Days 20-30, she recommends stopping any sort of fasting as your hormones are on the decline. This is when your body wants to rest and recover. Instead, focus on nurturing your body to prevent any excess stress.

Once you get your period, you restart the cycle.

CONTINUOUS FASTING CYCLE CHEAT SHEET:

● Days 1-4 (Menstrual phase into Follicular Phase): 13 Hours minimum

(increase if comfortable)

● Day 5: 15 Hours minimum (increase if comfortable)

● Days 6-10 (Follicular Phase): 17 Hours minimum (increase if comfortable)

● Days 11-15 (Ovulation Phase): 13-hour fasting

● Days 16-19 (As you end ovulation): around 15-hour fasting or more

● Days 20-30 (or until you are done ovulating): stop fasting

Conclusion

Furthermore, women can fast but are programmed for metabolic switching rather than following a typical male fasting regimen. In championing women's health, this

blog serves to include women in as many aspects of health as possible rather than depriving women of the myriad of benefits fasting can offer; the misconception that

claims women should avoid fasting is a result of the lack of research exploring how the female reproductive cycles work in conjunction with fasting. By aligning fasting

with the hormonal cycle, women can use fasting as a strategic tool for health optimization.

Citations

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effects of exercise training and intermittent fasting on body composition and

cardiometabolic health in adults: a systematic review and meta-analysis. Nutr

J 23, 7 (2024). https://doi.org/10.1186/s12937-023-00909-x

- Vasim I, Majeed CN, DeBoer MD. Intermittent Fasting and Metabolic Health.

Nutrients. 2022 Jan 31;14(3):631. doi: 10.3390/nu14030631. PMID:

35276989; PMCID: PMC8839325.

- Walsh JJ, Edgett BA, Tschakovsky ME, Gurd BJ. Fasting and exercise

differentially regulate BDNF mRNA expression in human skeletal muscle. Appl

Physiol Nutr Metab.