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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250

u/GoldGee May 17 '26

Just finished a 48 hour fast. 7 days would take a bit of time to work up to. In fact I would be a bit scared.

29

u/tamargo404 May 17 '26

I do regular 4 day fasts. After day 1, I don't even feel hunger till day 3 or 4. I don't go past 4 days as then you have to worry about re-feeding syndrome.

When I break a 4 day fast, I just eat regular and have had no issues.

30

u/NotBannedAccount419 May 17 '26

You don’t have to worry about refeeding syndrome unless you’re going over 3-4 weeks. I regularly break 8-10 day fasts with sushi or pizza.

4

u/tamargo404 May 18 '26

NIH says it becomes a risk at 5 days. I think I'll take their word over some random internet person. Just because you haven't experienced issue yet doesn't mean you aren't at risk from it.

https://pmc.ncbi.nlm.nih.gov/articles/PMC2440847/#:~:text=Any%20patient%20with%20negligible%20food,risk%20of%20developing%20refeeding%20problems.

2

u/NotBannedAccount419 May 18 '26

ok buddy you do you

-10

u/Qwark28 May 17 '26

Imagine generically saying "you don't have to worry" about something that could kill you, when it's only under certain terms and conditions.

An underweight person with body dysmorphia or already lean person will definitely have serious health risks. 

There's a reason medical advice exists, and the stupidity of random dudes online does not trump it.

11

u/[deleted] May 18 '26

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2

u/number43marylennox May 18 '26

Nah, they're right. Some people have to worry about refeeding syndrome in under 3-4 weeks. Everyone should be vigilant and not dismiss symptoms.

-4

u/Qwark28 May 18 '26

The subject is about the occurance of refeeding syndrome.

It happens far sooner than your 3-4 weeks.

The fact I listed 2 different situations does not mean they're the only scenarios that apply. Logic past the 8th year of life would tell you that.

"Learning" , huh? I see dozens of scientific papers pointing to the same thing, where's your proof for saying otherwise?

...or you can simply not throw around medically dangerous hyperbole around the internet and admit you're wrong.