Intermittent fasting (IF) has become a popular approach for weight management and longevity. But how does it affect hormones like insulin, cortisol, estrogen, and thyroid function?
Fasting Protocols
- 16:8 (most popular): eat within 8 hours, fast for 16
- 5:2: normal eating 5 days, calorie restriction 2 days
- OMAD: one meal a day, advanced users only
Hormonal Impact
- Insulin: levels drop, improving fat metabolism
- Cortisol: may rise during early adaptation—important to monitor stress
- Estrogen/Progesterone: in women, extreme fasting may affect cycle regularity
- Thyroid: prolonged fasting may reduce T3 in sensitive individuals
Best Practices for Women
Fasting during follicular phase is better tolerated. Start slow (12–14 hour fasts), especially if under stress or with irregular periods.
FAQ
Q: Can I fast during menstruation?
A: Most experts suggest reducing fasting intensity during menstruation.
Q: Is fasting good for PCOS?
A: Yes, it may help with insulin resistance—but only if done gently and consistently.
User Comments
- “I feel more focused during fasted mornings, but I eat early evening.”
- “Cycle tracking helped me avoid overdoing it.”
Editor’s Note
Fasting is a tool—not a rule. Use it with awareness, especially when hormones are in play.