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Comment by tejohnso | Hacker News Reader

Noted that the underlying cause for the improvement comes from ketones. This should indicate that intermittent fasting would also show similar results. Low carb diet, keto diet, intermittent fasting, they're all just different ways to switch the fuel source from glucose to ketones.

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Would a time restricted feeding type of intermittent fasting, with a 16/8 schedule, really result in the production of ketones? I thought that it would take about a day and a half or longer to exhaust carbs and start the switch to ketones. Then it’s only the longer fasts (like 5/2 days) that could help.

If you pee gets more yellow in that time period (I think) its indicative of ketosis. If anyone is more knowledgeable than me please chime in.

I.. don't think that's true at all. Ketones in your urine is indicative of ketosis. Smell of alcohol on breath is indicative of ketosis. Urine color is not an indicator for ketosis, it's an indicator for hydration.

You are correct. Urine color is an indicator of hydration. But sugar in your urine will cause your urine to be cloudy and more opaque. I've noticed that when I'm in ketosis that my urine is super transparent (just looking at transparency/opaqueness, not at color).

I'm no expert, but from my vast knowledge gained through the internet[1], it seems that ketosis starts at around the 12 hour mark. But I think it would depend on how glucose saturated you already are.

[1] I like Dr. Berg's videos https://www.youtube.com/watch?v=mSwOreYDPCM and anything from Peter Attia https://peterattiamd.com/

The easiest way to tell is to actually test your blood: https://www.amazon.com/gp/product/B0789G8KTG/

Wouldn't just plain calorie restricting also result in ketosis at night? The way I read the headline is "Not overeating might make you healthier"

I think it would depend on how close you are to ketosis before you start calorie restriction. And how severely you restrict. And probably a dozen other variables.

There's a lot of exciting research going on in this area but I believe that what you're hinting at is true. All of the things we know we should do, actually work. For whatever reason. Don't eat too much, go without sometimes, when you do eat, don't eat garbage, exercise on occasion, etc.

This also lends support to "bonk training", which is an exercise fad designed to exhaust glycogen stores and then continue working out, just as a distance runner that hits the wall continues beyond to finish the marathon, or a cyclist that bonks keeps pedaling to finish the leg.

I think the point is to get your body to make the glycogen to ketone switch more smoothly, and after the bonk every calorie you burn comes directly from fat stores. For most people, exercising in ketone-mode is absolute misery, you physically can't perform at more than about 80% of what you could do with glycogen, and you can't pass your lactate threshold. So bonk trainers do that. On purpose.

> This should indicate that intermittent fasting

I came to comment the same thing. First an aside that I agree with Peter Attia that IF is a confusing term, and instead Time Restricted Feeding (TRF) should be used. The current thought seems to be that many of the benefits from TRF (ie, skipping breakfast) come from causing the body to start generating ketones.

I'd be cautious if you're doing TRF by skipping breakfast.

>Interestingly, TRF improved weight loss and cardiometabolic endpoints—such as insulin levels, insulin sensitivity, and blood pressure—when participants ate early or in the middle of the day [18,19,41,42,43,44,45], but worsened cardiometabolic health or had null effects when participants ate late in the day [46,47,48].

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6627766/

IIRC subsequent studies have found that digestion interferes with sleep quality, which negates the benefits of TRF.

My largest meal of the day has naturally become lunch. My dinner is typically a few hours before bed. So, maybe I'm not bumping into what the study above found. I sleep fine.

Since I started TRF ~2 years ago I have dropped BF, and am the leanest I have ever been. I've always been very active and tend to exercise every day, but have never been this 'cut'. I also tended to eat ok naturally. I'm not a sweets person, and when I cleaned up my diet a few years back the main thing I dropped was potato chips (I love that crunchy, salty goodness). But even after cleaning up my diet I still wasn't getting the BF % I was interested so thought I'd give TFR a try. It's been awesome. I have more energy, and am in the best shape of my life.

Yep. But ketosis and intermittent fasting are complementary. It's just sooooo much easier to fast when in ketosis.

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