How to Fast for Fat Loss, Hormones, and Better Sex | Dr. Mindy Pelz
May 15, 2026
AI Summary
5 min readDr. Mindy Pelz, a fasting researcher and practitioner, spent a year doing what many health enthusiasts consider ideal: she ate one meal a day, performed multi-day water fasts several times a year, and felt incredible. Her weight dropped, her perimenopausal symptoms vanished. Then, at 45, her menstrual cycle stopped. Anxiety, which she had never experienced before, became a constant companion. Her hormones, she discovered through testing, were completely tanked. She had been fasting too much, and her body had responded by shutting down its reproductive system. This personal crisis became the foundation of her central argument: fasting is a powerful tool, but for women, it must be timed to the menstrual cycle, not applied as a one-size-fits-all protocol.
The Two Energy Systems and the Principle of "When"
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What you'll learn
- 1 (02:07) **Two Energy Systems: The Core Principle of Fasting** - Dr. Mindy Pelz introduces the foundational idea that the body has two energy systems: one when eating and one when not eating.
- 2 (05:08) **Overcoming the Initial Hunger and Fatigue of Fasting** - The host asks when the "unlimited feeling" kicks in, given that early fasting often feels unpleasant.
- 3 (06:55) **Best Fasting Window: Morning vs. Night** - Dr. Pelz resolves the debate on whether to skip breakfast or dinner.
- 4 (11:06) **What is Fat and How Does the Body Store It?** - Dr. Pelz reframes the purpose of body fat as a protective mechanism.
- 5 (12:39) **Key Differences: Fat Burning for Men vs. Women** - Dr. Pelz explains why a "little bit of fat" is biologically necessary for women.
- 6 (16:33) **The Power of Safety, Pheromones, and Cycle Syncing** - The conversation explores why women's cycles sync up and the role of feeling safe.
- 7 (26:18) **The Fasting Cycle for Women: Day 1-10** - Dr. Pelz breaks down how to fast and exercise according to the menstrual cycle, starting from the first day of bleeding.
+ Full timestamped outline available in the app
Show Notes
Every diet you've ever tried has failed you for one reason: it never told you when to eat.
Your body runs on two energy systems. One burns sugar. The other burns fat. Most people never spend a single day in the second one.
Around eight to ten hours without food, the switch flips. Ketones flood your brain. Hunger quiets. Mental clarity hits. Healing turns on. This is what fasting expert Dr. Mindy Pelz has been teaching for over 25 years, and what her book Fast Like a Girl made impossible to ignore.
For women, timing is everything. Day 1 to 10, fast longer and lift heavier. Day 11 to 15, testosterone surges and libido climbs. Day 16 to 19 is for deeper fasts. After day 20, progesterone needs you to back off and rest. Fast like a man during the back half of your cycle and you'll tank the very hormones keeping you calm and regular.
Underneath all of it sits the hormonal hierarchy. Oxytocin at the top. Cortisol below it. Then insulin. Then sex hormones. When you feel safe and connected, the whole stack works. When you don't, nothing else matters. Connection isn't optional for women. It's biology.
Dr. Mindy’s books:
- Age Like a Girl How Menopause Rewires Your Brain for Mental Clarity, Increased Confidence, and Renewed Energy
- Eat Like a Girl: 100+ Delicious Recipes to Balance Hormones, Boost Energy, and Burn Fat
- Fast Like a Girl: A Woman's Guide to Using the Healing Power of Fasting to Burn Fat, Boost Energy, and Balance Hormones
- The Menopause Reset: Get Rid of Your Symptoms and Feel Like Your Younger Self Again
- The Reset Factor Kitchen: 101 Tasty Recipes to Eat Your Way to Wellness,Burn Belly Fat, and Maximize Your Energy
- The Reset Factor: 45 Days to TransformingYour Health by Repairing Your Gut
In this episode you will:
- Learn the fasting cycle for women, Dr. Mindy's day-by-day framework that syncs your fasting window, workout intensity, and food choices to your menstrual cycle
- Uncover why your menstrual cycle is a monthly detox rather than a burden, and what an irregular or absent cycle is actually telling you about your body
- Discover why timing your eating matters more than what you eat, and how the ketogenic energy system unlocks fat burning, mental clarity, and steady energy
- Understand the hormonal hierarchy, how oxytocin, cortisol, insulin, and sex hormones stack on each other, and why female community and connection fun
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