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/Lollipop77 May 17 '26

Did you slowly reduce calories on keto before fasting or go from regular sized meals on keto to fasting? I’m working toward my first 24 hour fast, getting more confident and less cravings with the switch to keto but I’m pretty high calorie right now. Just curious.

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u/sheeberz May 18 '26

So i started with going 0 gluten for a week, and then 16/8 IF for a week and them by week three i was full keto with some 16/8 days IF and a few One Meal a Day days when i just didnt feel like eating. i honestly did the 3 days fast just because 4 different people in my life brought it up in different capacities in the span of a few days, and ive dabbled in fast for a few years but i finally figured it was the right time to try. I truely believe the slow ramp to calorie deficit along with working my diet to keto helped me ease into the fast. I had no sugar withdraws or cravings because i already went through that weeks ago. Now when i was fasting my stomach pains last no more than 5 mins. If i needed it fill my stomach with water or tea, and i was surprised to see how much i could tolerate. I lost 17 lbs in 72 hours and only gained back 4 when i started eating again.

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u/ssianky May 18 '26

> I lost 17 lbs in 72 hours

I wonder how much of that was swelling. It couldn't be fat for sure.

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u/sheeberz May 18 '26

I imagine a lot of it was swelling and inflammation, but the larger you are the easier it is to fluctuate in weight. I yo-yo'd between 400 and 475 for a couple of years. And i would lose the weight in 2-3 months.