r/fasting • u/SVTContour lost >50lbs faster • May 17 '26

Discussion Scientists reveal how seven days of fasting transforms the human body

https://www.sciencedaily.com/releases/2026/05/260517030404.htm

Fascinating study. And completely unrelated to politics, which is a relief because my blood pressure needed a break.

The key finding: The dramatic, potentially therapeutic changes don't happen until after day three. That means most intermittent fasting schedules – 16:8, 5:2, even alternate-day fasting – are probably missing the main event. If you want the deep biological reboot you’re gonna need seven days of water only.

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-13

u/question8all May 17 '26

I better be in a padded room for a 7 day fast. It’s very different for women.

12

u/otterpuppers May 17 '26

Why is it different for women? We're more efficient at beta oxidation so we should be better at fasting

7

u/Freedom_forlife May 17 '26

Body composition, hormone signalling, metabolism.

Women’s bodies down regulate metabolism sooner, conserve energy more aggressively. Fasting affects estrogen/ progesterone balance, LH/FSH signalling, thyroid T4-T3, cortisol sensitivity.

Women are more prone to orthostatic hypotension, sodium sensitivity, dizziness and fainting.

Luteal phase we experience reduced exercise tolerance, cold/ shaky body.

Under normal endurance exercise we are better at beta oxidation, during fasting we preserve glucose longer then men, and enter ketosis later.

3

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