Evidence that overnight fasting could extend healthy lifespan [pdf] | Hacker News Reader

Evidence that overnight fasting could extend healthy lifespan [pdf]

media.nature.com

53 pointsXzetaU854 comments

I've tried a few variations of fasting over the last ~3 years and here's what works best for me. Because I tend to snack, I have time-boxed my eating windows inline with a fasting schedule, so:

- No breakfast, just black coffee - First eating window (~11am - 2pm) - Second eating window (~5pm - 8pm) - No eating after 8pm

I've played with three eating windows and it also works quite well. I cheat on weekends, Fridays and sometimes in social situations. Most important thing to note: build a routine that works for you, nothing is sustainable if it isn't built around your specific lifestyle. If it doesn't work for your lifestyle, it will never sustain.. think about it as product market fit for your body + health.

> think about it as product market fit for your body + health

Willpower and default behaviors as a currency is how I think about it.

I found eating at 2pm and 8pm worked for me. In the morning, if you don't eat, your digestive system seems to remain inactive so you're not that hungry until 2pm. By eating at 8pm you're eating late enough that you'll be asleep before you get hungry and want to snack. This gave me 18 hours of fasting, 12 hours digesting the last meal and about 6 hours of my body burning my fat stores for energy.

I combined this with reduced carbs so when I did eat, it was a longer time before I felt hungry because reduced carbs means not getting the sugar rush and then the crash a couple of hours later where you feel very hungry.

> in fruit flies

Yeah @dang could we have a title edit please? This headline is grossly misleading.

that's what I also came here to say....

It doesn’t mention that autophagy in humans takes several days. Overnight fasting might help us but not for the reasons implied here.

I’ve never found good research on autophagy. Has anyone pinpointed when it starts?

https://www.medicinenet.com/how_long_do_you_need_to_fast_for...

Says 2-4 days.

From the article:

> There are, however, no conclusive studies on humans that indicate an optimal period of fasting to achieve autophagy

Why do they even need fruit flies to do this kind of study? How difficult would it be to find human subjects for this?

It takes much longer to test this on humans, because of the greater average lifespan.

Human subjects have a lot of rules around their use.

Apart from the other points mentioned, I want to add that funding could be a potential issue for studies based on human subjects. More expensive and time consuming compared to studying flies.

The general flow of such research is to test various hypothesis on animals and then move forward to human studies only for the most promising ones.

https://en.wikipedia.org/wiki/Institutional_review_board

Don’t all humans fast overnight pretty much always?

This article discusses 20-hour long fasting periods that include a night, say from 2 PM till 10 AM the following day.

Also note that it did 20 hour fasts for a fruit fly. Fruit flies metabolism acts a bit quicker than humans, that would probably correspond to a multi day fast for a human.

Yes, and you "break" the "fast" every morning.

I see what you did there.

Good use of the period at the end!

> I see what you did there.

It's not a play on words, "breaking the fast" is where the word comes from :).

I know. I was being humorous!

My mistake! Have a pleasant day :)

8 hours between meals isn't fasting by any definition. That is the average you get when you eat the normal 3 times a day.

> 8 hours between meals isn't fasting by any definition.

Funny what we call eating in the morning then, isn't it? (also, not everyone eats only at designated meal times. People snack.)

> Funny what we call eating in the morning then,

Sure, but ostensibly we're not eating right before bed.

If dinner is at 7 or 8 and breakfast is at 7 or 8 that's 50% more time than an equal meal distribution throughout the day.

for 20 hours?

Nope, lots get up in the middle of the night to eat.

Surely that is an eating disorder or beginning of one?

I am not sure. I have a sister who used to do that and she wasn't overweight neither had any obvious eating disorder. Maybe it was because she was an athlete? I know other people with obvious weight problems that wake up in the middle of the night to eat and maybe for those it might be considered a disorder.

> athlete

I've heard of strength training regimens that call for a middle of the night protein shake supplement. But given how crucial rest is, I've always been skeptical of that idea.

These people that want to live in their 80s or beyond boggle me. Who wants to stick around that long when you have so many contemporaneous failures of the body all crashing down on you? Better to just die catastrophically in your early to mid 70s and save yourself a drab decade or two.

Some people are healthier in their 80s than others in their 60s. The point is to be healthy for as long as possible.

If you're not careful, your body will start failing at age 65 and you'll live a drab decade until croaking at 75.

If you want to avoid that, and want to stay healthy and vibrant until 75, you have pretty much the same goals as someone who wants to live to 95.

Not so sure after all: https://www.bbc.com/news/magazine-16964783

Half of the developed world has an eating disorder.

Little more data and research on fasting: Fasting is fountain of youth:

https://www.cnn.com/2018/10/01/health/fasting-longevity-food...

Even 16h-8h fast-feed periods are great for long-term health. Skipping breakfast with plain coffee for me have worked perfectly. Now I'll transition to a 8am-4pm feed period schedule, I've heard that it may improve sleep quality going with empty stomach to bed.

edit: commenter shared [0] which disproves my understanding. Intermittent fasting, when controlled for calorie (and protein) intake, had a healthy outcome than a 'normal' diet, but the sample size was only 14 women per group (IF and control).

I wish they would have stricter diets in the study. They control for smokers, but I wonder if participants in one group consume alcohol or deep-fried calories more than the other. Or even one group getting better sleep than the other group.

[0] - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6735806/

----

My understanding is that Intermittent Fasting (IF) is built on shaky science b/c research doesn't control for calorie reduction (CR).

There are papers that suggest CR improves longevity. There are papers that say IF improves longevity, but I haven't found any research that says IF without CR improves longevity. IF studies allow subjects to eat unrestricted during food periods, but don't actually record how many calories are consumed. We don't know if the subjects (unintentionally) also CR during IF.

If IF helps people CR, then great, but I think its misleading to say that IF actually has direct health benefits.

You're understanding is limited.

For a nice review check out this one [1]. Although most of 16:8 effects are minor, they build up over time.

[1]: https://examine.com/supplements/16-8-intermittent-fasting/

For a nice coverage of the effects, here:

https://examine.com/supplements/16-8-intermittent-fasting/re...

oo! thank you for this. I updated my comment.

> TRF 2826 ± 412.3 kcal/day, carbohydrates 53.2 ± 1.4 %, fat 24.7 ± 3.1 %, protein 22.1 ± 2.6 %

> ND 3007 ± 444.7 kcal/day, carbohydrates 54.7 ± 2.2 %, fat 23.9 ± 3.5 %, protein 21.4 ± 1.8)

Any ideas why the TRF group has less calories and more protein than the ND group in the linked study linked in the article [0]? _Maybe_ the TRF group has smaller humans than the ND group, but then why would TRF have a higher protein diet?

> Some studies have found that 16:8 can preferentially reduce fat mass while sparing muscle, but further research is still required to confirm this

Bro-Science Body Builders know that a high protein diet + calorie restrictions are perfect for cutting abdominal fat. I don't see what value IF provides here.

[0] - https://pubmed.ncbi.nlm.nih.gov/27737674/

Not trying to be snarky here but is 16pm supposed to be 6pm? 14 hour fast?

Usually the feed window is 8 hours so they probably meant 8am-4pm (and probably messed up converting 0800-1600)

I’m guessing it’s actually 4pm — 24h number incorrectly written with a pm.

haha yeah. sorry about it. I meant 8:00 - 16:00 hrs.

How can you have a 28 hour feeding cycle? The article states that they alternated a 20 hour fast with a 28 hour feeding cycle. Doesn't the 28 hour feeding cycle also include a fast since the fruit flies will sleep at night?

would some IRB clearance be needed for this study? Would fruit flies have any IRB concern?

I haven’t read the artical yet but doesn’t everyone fast overnight?

Many people snack right up until bedtime (sometimes even literally in bed) and then rush to feed again the second they wake up. So technically, there is a fast during sleep, but technically, there is a fast every second you don't have food in your mouth, I suppose.

The point is, duration is important. I don't know if there's a standard, but in the intermittent fasting literature, 18/6 is one of the common schedules, so you'd eat from noon to 6pm for example. The other 18 hours would be 0 calorie intake hours.

Rather than fixed schedules, what you need is a period of time long enough that your body enters ketosis rather than using energy directly from glucose. The schedules are a rough guideline.

The subtitle speaks of prolonged overnight fasting.

Next time someone asks if I've tried fasting

- Yeh, I'm doing overnight fasting

I fast every week once (dinner to dinner). I find the benefits overall - 1. Better control on cravings for food. 2. Feel quite relaxed internally by evening. 3. Slight weight loss.

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