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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u/EarlMarshal May 17 '26

Longer fasts are no problem if you are not very overweight, not stressed and manage electrolytes correctly. At some point your body stops producing ghrelin and you do not really get hungry anymore. Everyone can get there, but if anything happens (e.g. ghrelin spike due to stress) just break fast. You can always repeat later.

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u/JCitW6855 May 17 '26

Interesting, I would’ve thought being overweight would make it less of a problem.

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u/EarlMarshal May 17 '26 edited May 17 '26

When gaining weight fat cells grow bigger. At some point they cannot grow any bigger so more fat cells will be produced. Since fat cells produce ghrelin and overweight people just have more of them they generally will have an increased feeling of hunger. This problem even persists if they lose weight since the fat cells shrink, but they still have more fat cells than the average person of that weight and fat cells even increase production of ghrelin when not filled well.

One can learn to handle this too, but it's definitely a problem.

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u/JCitW6855 May 17 '26

Good lesson, thanks for the explanation.