Intermittent fasting for women: How it affects hormones
By Camille Styles | Published: 2025-10-24 10:00:00 | Source: Camille Styles
“I believe feeling our best comes when we learn to listen to our bodies — and one thing I’ve personally noticed over the years is that I’m more energetic when and after I do intermittent fasting. When I’m consistent with a rhythm that works for me, I have consistent energy, better digestion, and I find it easier to maintain my weight without stressing over every bite.
But here’s the key: I am Not rigid About the fasting schedule. If I wake up really hungry, I eat. If it’s the week before my period, I skip the fasting altogether. Intermittent fasting, for me, is about listening to my body and tapping into that intuition – not “forcing” anything.
My current approach is mostly inspired by Dr. Mindy Belz’s book, Fast like a girl. Her research is about how women can fast in a way that supports our hormones, rather than working against them. I sync my fasting habits with my menstrual cycle: For most of the month, I typically follow a 16:8 fast (an 8-hour eating window, between 10am and 6pm, for example). During the luteal phase (the week before my period), I don’t fast at all. During the follicular phase, I like to try fasting for a little longer, when I feel my energy is naturally higher.
This flexible approach has been a huge game changer for me. But it’s not just anecdotal experience — there’s real science behind why intermittent fasting can support women’s health, increase longevity, reduce inflammation, and bring a whole host of other health benefits.
To help us dig into the research, Lauren Zielinski, MSN, CNM, a registered nurse, midwife, and women’s health expert, shares practical tips for approaching intermittent fasting in a grounded, supportive way.
Lauren Zielinski, MSN, CNM
Lauren Zielinski is a Certified Nurse Midwife with over 11 years of experience in the field of women’s health and obstetrics. She studied medicine at the University of Colorado Denver with a focus on community health and working in birth centers.
The science behind intermittent fasting
“There is an abundance of research behind intermittent fasting,” Lauren says. “While it is.” He can It leads to weight loss, and the benefits are much deeper than that. Research has shown its ability to “clean cells,” increase longevity, and reduce the risk of common diseases such as diabetes and heart disease. Intermittent fasting maintains healthy DNA and cells, and can slow the aging process. I think this is the closest thing to a fountain of youth
Lauren explains that intermittent fasting is not a fad, it has been studied at leading research institutions including the USC Longevity Institute and Harvard University, and studies link it to improved metabolic health, reduced inflammation, improved brain function, and increased longevity.
How fasting actually works in the body
On a normal day, your body uses glucose from food for energy. But when you fast, fasting switches from burning sugar to burning stored fat, a process called Metabolic switch (A term coined by Johns Hopkins neuroscientist Mark Mattson, Ph.D.).
This switch doesn’t just help with fat loss. It triggers a cascade of cellular benefits. As fasting continues, your body’s glycogen stores deplete, and it depletes Ketone formation– Release of ketones into the bloodstream.
- Strengthening the body’s defenses against oxidative stress
- Help remove or repair damaged cells
- Improve blood sugar regulation
- Increase resistance to stress and reduce inflammation
Even more amazing, ketones stimulate the release of BDNF (brain-derived neurotrophic factor), a molecule that strengthens neurons and synaptic connections, and supports memory and cognitive health.
“Think of fasting as a little ‘spring cleaning’ for your body,” Lauren says. “You give your system a break from constant digestion, allowing your cells to repair and replenish.”
Unique considerations for intermittent fasting for women
While intermittent fasting can benefit almost everyone, women’s hormones make it especially important to approach it with flexibility. “Women are not just smaller men,” Lauren emphasizes. “Our hormonal fluctuations throughout the month mean that fasting can be great at certain times and draining at other times.
Here’s a simple guide based on what research and many women (including myself) have experienced:
- Follicular phase (day 1-14): Estrogen is rising, and energy is higher. This is often the best time to try a longer fast (14-16 hours).
- ovulation: Continue moderate fasting if you feel comfortable, but listen to your body.
- Luteal phase (the week before menstruation): Cortisol is more sensitive, and your body may need more nutrition. This is the time to Reducing fasting Or skip it completely.
- Menstruation phase: Many women feel better with gentle fasting or feel nothing at all during their period.
This periodic approach works best for me. This is also what Mindy Pilz and many hormone experts recommend: respecting your cycle, rather than sticking with it.
Long-term benefits of intermittent fasting
A 2019 New England Journal of Medicine review of fasting research found significant and wide-ranging benefits, including:
- Cognitive function: Improve memory and mental clarity
- Heart health: Improve blood pressure, cholesterol and resting heart rate
- Metabolic health: Improve insulin sensitivity and reduce the risk of type 2 diabetes
- Physical performance: Enhance endurance and maintain lean muscle
- longevity: Improving cellular repair mechanisms that may slow aging
For me, these benefits manifest as sustained energy, improved digestion, and feeling more in tune with my body’s signals.
How to start intermittent fasting gently
If you’d like to try fasting, here’s Lauren’s mindful approach:
- Start with 12 hours Between dinner and breakfast.
- After a week or two, extend to 14-16 hours If it feels good.
- Stay hydrated, water, black coffee and herbal tea are your best friends.
- Focus on nutrient-dense foods during mealtime to support hormones and blood sugar balance.
- “Give your body 3-4 weeks to adapt. It’s normal to feel tired or uncomfortable at first,” says Lauren. “This usually passes as your metabolism adjusts.”
And perhaps most importantly: it doesn’t have to be all or nothing. If you wake up hungry, eat. If your body needs more fuel during certain phases of your cycle, listen up.
When should intermittent fasting be avoided?
While intermittent fasting can be beneficial, it is not right for everyone. Lauren advises against fasting if you:
- Under 18 years old
- Are you pregnant or breastfeeding?
- You have a history of eating disorders
- Having diabetes or other blood sugar disorders
Always check with your healthcare provider before making major changes to your eating routine, especially if you have underlying conditions.
Food freedom, not restrictions
For me, intermittent fasting is not about restrictions. It’s about finding a rhythm that supports my energy, mood, and hormones — and being flexible when my body needs something different.
Lauren sums it up perfectly:
“When done thoughtfully, intermittent fasting can be a powerful tool to support women’s health, but the key is flexibility. Our hormones are dynamic, and our approach to fasting should be too.”
References and sources:
- Belz, M. Fast like a girl (2022)
- Mattson MP et al. “Intermittent fasting and human metabolic health.” New England Journal of Medicine2019.
- National Institute of Health. “Ketogenesis and the response to cellular stress.”
- USC Longevity Institute; Harvard Medical School studies metabolic switching.
This post was last updated on October 24, 2025, to include new insights.
(Tags for translation)Healthy habits
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