The impact of intermittent fasting on female hormone health

Whilst there are incredible benefits of intermittent fasting on factors, such as reducing weight and improving insulin sensitivity, and therefore preventing diabetes, fasting can have a negative impact on the delicate web of hormones in women.

The menstrual cycle and reproductive health are sensitive to changes in energy balance and nutritional intake. Some studies suggest that intermittent fasting, especially more extreme forms, might lead to disruptions in menstrual cycles or other hormonal imbalances in some women.

For example, we know that fasting is a ‘stress’ on the body, leading to increases in cortisol - our primary stress hormone. It’s important to first note that not all stress is bad, however. Deliberate stressors, such as fasting, exercise, heat and cold therapy (sauna and cold plunges), can actually lead to positive adaptive changes. However, when someone’s overall stress burden is consistently high due to other lifestyle factors - work, financial burden, sleep quality, relationships, environmental toxicity - this is when additional stressors, such as fasting, may not be appropriate, particularly in women.

What are the potential impacts of fasting on sex hormones in women?

Suppression of Reproductive Hormones: Prolonged or chronic stress can lead to the suppression of the reproductive axis, affecting the release of gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), and follicle-stimulating hormone (FSH). This suppression can subsequently impact ovarian function and sex hormone production.

Energy Deficiency: If intermittent fasting leads to a significant caloric deficit or insufficient nutrient intake, it could result in energy deficiency. This can negatively impact reproductive health and disrupt normal hormonal signaling.

Cortisol and Androgens: In some cases, chronic stress may lead to increased production of adrenal androgens (male sex hormones produced by the adrenal glands). Elevated levels of androgens can contribute to conditions such as polycystic ovary syndrome (PCOS) and may further disrupt hormonal balance.

It’s important to highlight that there is always a level of individual variability - not all women will respond the same way and what works for one woman may not work for another. Intermittent fasting may have a positive impact on your health, but it is recommended to work with a healthcare practitioner to do this safely and assess how this practice may be impacting your health.