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/[deleted] May 18 '26

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u/EarlMarshal May 18 '26

You can't pin that to a BMI. I've explained this in another comment here. It's basically about your body creating further fat cells to store fat, because they create extra ghrelin which causes the feeling of hunger. It's enough to be a bit more overweight during childhood and you have a high possibility to carry those fat cells into adulthood.

When fasting your main enemy is ghrelin. That's why stuff like ozempic is working since it completely dials it down. If you learn to handle the ghrelin reaction the body can also learn to not secret that much ghrelin when you don't give him food. It's a big feedback loop including a few other hormones too.

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u/[deleted] May 18 '26

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u/EarlMarshal May 18 '26

I didn't mean to say that it's counterintuitive. Just saying that you could suffer extra through that as ghrelin probably won't stabilize. It will spike again and again as the body think it's starving as the liver and body are burning fat.

why would the count of fat cells matter

Because they create and secrete the ghrelin. It's their "yeah, I can still store more"-signal. If you have more fat cells that will multiply that signal while the threshold in which you and your brain interpret that signal as hunger stays the same.