Female ovaries: ~100,000 mitochondria per egg
Each human egg cell contains approximately 100,000 mitochondria, making female ovaries acutely sensitive to energy availability and fasting signals.
Snapshot · The Diary Of A CEO with Steven Bartlett
Women’s Fitness Expert: What You NEED To Know About Dieting & Exercise | Dr. Stephanie Estima
Explore episode
Jun 29, 2026
Where this was said
Is Fasting Safe For Women?
At 28:08 · chapter starts 26:11
Dr. Estima's third myth targets long fasting windows — 20, 24, 36, 72 hours and beyond. The female body is uniquely sensitive to energy availability because it has to decide each cycle whether conditions are safe for pregnancy. With 100,000 mitochondria per egg cell, ovaries are extraordinary energy scanners. Prolonged fasting signals famine, shutting down ovulation. Rather than extended fasts, Dr. Estima recommends a natural overnight fast: stop eating 2–3 hours before bed, sleep 8–9 hours, eat breakfast — totalling 10–11 hours of fasting. Pushing the eating window further compresses the space available to consume sufficient protein, calories, and macros. [1] — Dr. Stephanie Estima "Extended fasting windows don't just restrict calories — they send a famine signal to a woman's ovaries, which contain roughly 100,000 mitoc…" 27:09
Women have 10-20x less testosterone than men
Women have 10 to 20 times less testosterone than men, which is why even identical training programmes produce far less muscle mass in women.
Long fasts risk hormonal disruption
Fasting windows of 20, 24, 36, or 72+ hours can signal famine conditions to the female body, suppressing ovulation and disrupting hormonal cycles.
How Long Fasts Quietly Damage Female Hormones
Extended fasting windows don't just restrict calories — they send a famine signal to a woman's ovaries, which contain roughly 100,000 mitochondria per egg and are constantly scanning the environment for safety. The result: suppressed ovulation, disrupted cycles, and cascading hormonal damage.
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