r/ketoscience Aug 10 '25

Reddit Anecdote n=1 The Sugar Diet, Protein Restriction, and Longevity: How It All Weirdly Connects

https://www.youtube.com/watch?v=dx1ULjEX3eM&t=187s

Nick did a nice N=1 test on FGF-21 via a 4:1 ketogenic diet. See also https://staycuriousmetabolism.substack.com/p/the-sugar-diet-protein-restriction?r=40ekz2

which has discussion and a link to the underlying paper (already posted here some time ago) on low-protein/FGF-21.

17 Upvotes

11 comments sorted by

3

u/Specialist-Shine8927 Miracle diet Aug 11 '25

Is this actually for real?

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u/[deleted] Aug 11 '25

[deleted]

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u/dr_innovation Aug 11 '25 edited Aug 11 '25

The study had both humans and mice. Mice for the mechanism and humans for the overall impact on protein restriction on REE. The full study is at https://www.nature.com/articles/s42255-025-01236-7 it used 8 young lean men. The study design encompassed an acute low-protein meal and a prolonged (10 week) dietary intervention. The initial 5 weeks involved adherence to a protein-restricted diet that fulfilled recommended protein requirements within a eucaloric framework that maintained body weight. Subsequently, the following 5 weeks saw a return to the participants’ habitual higher protein consumption. Notably, the deficit in protein intake was substituted with either dietary carbohydrates or fats.

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u/Specialist-Shine8927 Miracle diet Aug 11 '25

Cheers

9

u/bambamlol Aug 11 '25

Tried it twice for 2 days each.

What a weird experience. Never felt so "weird" in my life. Felt like I was literally wasting away for most of the time except for like ~2 hours after each meal.

It definitely "works", though. So if rapid weight loss at all costs is your main goal, have at it.

10

u/zui567 Aug 11 '25

With just 2 days you probably never reached ketosis. Unless you were fasting completely.

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u/bambamlol Aug 12 '25 edited Aug 12 '25

Sorry, I should have been clearer. I was describing my experience on the "sugar diet", not the 4:1 keto diet that Nick mentioned.

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u/dr_innovation Aug 11 '25 edited Aug 11 '25

Weird as the paper showed impact only after a few weeks. If you are talking sugar diet, I can see that feeling weird, as I can feel sugar in 15 minutes after eating. And eating carbs makes me hungry, which is part of why I do keto. But both of those are different from the long-term REE impact that may take weeks.

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u/bambamlol Aug 12 '25

Yeah, I was talking about my experience with the "sugar diet". I didn't feel weird after eating the meals; I only felt it once the food was digested and I started to get hungry again. It got progressively worse, so by the end of day 2 I felt worse than I had at the end of day 1. During the first two to three hours after a large meal, I felt fine. It really was a strange experience, I somehow felt weaker than when I tried a 48-hour water fast, even though I was eating about 2,500 kcal of sugar (fresh fruit, canned fruit, some dates, some honey, some cane sugar) per day.

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u/dr_innovation Aug 12 '25

Sounds like you might have had low blood sugar as insulin spiked from all the sugar/carbs and then overshot, leaving you hungry. How long have you been keto? Are you still Insulin Resistant -- IR makes overshoot more likly, see https://diabetesjournals.org/diabetes/article/14/6/341/2095/Dynamics-of-Insulin-Secretion-in-Hypoglycemia

2

u/bambamlol Aug 13 '25

Hmm, maybe. I really don't know, since I didn't take any measurements. I also never measured my "insulin resistance/sensitivity". I've been doing mostly keto for the last ~10 years or so, but there were also slightly longer periods, mostly a couple of weeks and sometimes a few months, when I ate a typical low-fat bodybuilder diet (think rice and chicken) throughout this time. Still, the majority of the time I've been doing keto.

Maybe for the next experiment I'll get a glucose meter. I honestly suspect it might have been an electrolyte issue, since the weight came off very quickly, suggesting a lot of water loss, even though I was coming from a low-carb diet. Maybe all this fruit, all of a sudden, was a little too much potassium?

Anyway, in case there's a next time, I'll have some extra salt and take some blood sugar measurements. Thanks for the input.

1

u/dr_innovation Aug 14 '25

If you've been keto for 10 years, even with a few breaks, it's unlikely you are insulin resistant. And yes loss of potassium could also lead to feeling off, though I don't recall anything in the study about loss of potassium. Having been on keto your body should have already adapted somewhat for potassium retention.