There are a couple different regimes to tease apart - intermittent fasting (IF), time - restricted eating (when you restrict when you eat to a certain number of hours per day - typically 12 or less) - sometimes included in the IF category, and calorie restriction. It's important to note that most of the animal studies done on calorie-restriction are also time - restricted eating (since the animals tend to eat their food until it's gone rather than spacing out their eating). I know there's some recent evidence that the two have overlapping but somewhat separable effects (other methods of IF- say alternating days with very low calories tend to also result in overall calorie reduction - meaning you don't end up eating extra on the other days).
You describe the differences between these different regimes very clearly in your subsequent post #12. That chart, and the article it’s taken from, will probably clarify this for many readers. For instance, I was under the impression that “intermittent fasting” refers specifically to leaving a 14-hour (or more) window of fasting within a 24-hour period, that is, fasting for that 14-hour+ duration. That's what I recall the articles I'd read as saying. That’s kind of inaccurate, as that table shows, my labeling I mean, although as you say there are overlaps.
I feel the same way ( I do time - restricted eating 14-20 hours per day) re: cognitive function (feeling clear-headed), and that's common. I'd go so far as to say it's non-controversial to say that IF/time-restricted eating has neuro protective effects - a recent
mechanistic paper
Okay, so this isn’t just my individual experience, or selective rah-rah-ing by enthusiasts, but actual established science. Good to know!
Re: that "cautionary" NPR article that quotes Valter Longo. He's well-respected, but prone to only advocating the method he came up with - 5 consecutive very low calorie (~600, AFAIR) days a month.
I'd encourage people to check out
David Sinclair's book - perhaps currently the biggest name in the aging field and a very nice guy (from both meeting him and what others have said).
But the overall take home on eating should be that eating all the time - unless its quite low calorie is bad for you - any way you can cut down (but still get adequate nutrition) is good. We know now that cutting down on calories definitely has those epigenetic effects, e.g.
Caloric restriction delays age-related methylation drift
I had to gloss over much of the overtly technical discussion in that paper up there, but absolutely, that seems pretty much conclusive, or at least that’s how the paper describes it as in very clear terms. Looks better and better!
One somewhat off-topic observation, though: I found it curious that the article starts off saying that the only “intervention” that increases lifespan across species is calorie restriction. In other words, not other kinds of “hormesis” (plural 'hormeses', I guess?), like cold shocks and exercise. We’d discussed this in the other thread; and although I don’t have links handy, but I’m pretty much sure that it’s generally agreed that exercise does increase your longevity, directly at the genetic level.
A
paper that shows human lifestyle factors associated with slowing the epigenetic aging clock. Spoiler: it's the usual suspects.
Again, had to gloss over the overly technical parts, but a very interesting read! As you say, the usual suspects.
The interesting thing, the nice thing, is that alcohol consumption, in moderate quantities, is a definite contributor (to increasing longevity). Now that’s the kind of scientifically-backed result that gladdens one’s heart to read!
If you want a deep dive on the latest- there was an aging meeting just two months ago with many of the biggest names that has made talks available freely online:
http://www.agingpharma.org/watch
That’s a great resource! Kind of advanced, though, for most of your garden variety lay reader, including yours truly. Listened to bits and pieces of some of those presentations, and have bookmarked the page, for a more leisurely listen-in later on.
My advice:
Yes - it may take time to see the epigenetic changes - but effects like Chanakya noted will be noticed fairly quickly. You also get used to going a bit longer without food, and not thinking you need to eat every 3-4 hours- I've found that freeing. Doing a few low calorie days a week is great as well. We can quibble about what the best (most likely there isn't one) regimen is, but but cutting down on calories & increasing time spent not eating definitely has beneficial effects.
I’d done this only “intermittently”, and for a short period; but this looks increasingly promising, as a more protracted lifestyle choice.
First, it takes a loooooooooong time to starve to death (> 30 days typically) or even to get seriously malnourished - look at pictures of actual starving people, if you can stomach it (so to speak). Hydration plays a big role. Check the popular medical web sites - even those (conservatively) say 72 hours is fine (I've done longer than that - biggest risk factor I found was getting a bit light headed on the 3rd day - which could be bad if driving, etc). Remember that for most of the ~200,000 years our species has been around we probably haven't been having 3 squares - we carry more body fat than our close relatives - probably as an adaptation to our wandering.
That being said, ease into it. And - as Longo and other studies have noted - you can get most of the benefits with low calorie days rather than pure fasts. Note one of the "good" things that happens during fasting is a process called autophagy, wherein cells recycle macromolecules and end up destroying damaged proteins, etc. To be clear, when you starve to death, you get too much autophagy - that's the whole thing about hormesis - is finding the sweet spot.
No, I wasn’t referring to malnourishment as such, far less actual starvation.
Okay, how do I put it. I could be way wrong here, in thinking/suspecting this, but it occurs to me -- and indeed that is the reason my own fasting regime I’d given up despite the fact that it worked great for me -- Do we really know with a fair degree of certainty that there are no negatives to this? Specifically, our organs, I don’t know, bile from the gall bladder, the liver, whatever other enzymes are let loose within our intestines to enable the whole complex process of digestion: I guess these are well enough adapted for the three-to-four-squares-a-day routine. Might these enzymes, the bile, whatever, continue to be released at those times by these glands, and might not having food available at those times to work on, end up resulting in some long-term damage going forward, ulcers and whatnot? Might these side-effects of a fasting regime show up after following this kind of a regime for years and years? Do we know enough to rule this out, to say with confidence that something like this doesn’t follow from a fasting regime?
I know, one can imagine all manner of ill effects arising out of all manner of causes; and generally one wouldn’t want a negative proved! But still, when one’s long-term health is what is on line here, I was wondering if this specific aspect has actually been studied, and if these different kind of fasting regimes have been okayed from this specific perspective.
Unless you're close to the edge of being deemed underweight, or have type I diabetes or another serious condition - a few days of fasting (with lots of hydration) is not going to hurt you. There was an
obese Scotsman who apparently went 382 days without food - he did get supplemental vitamins and electrolytes (what plants crave!
)
That’s actually over one full year! Hibernating bears come to mind, except he beats those bears flat!
Wouldn’t have thought this possible, yet this seems factual enough. (I confess, I plugged in ‘angus barbieri hoax’ into my search engine, and glanced through the first five or six pages of results, to make sure you weren't kidding, or mistaken. This seemed like a hoax, although the man doesn’t seem to have benefited from pulling the stunt, apart from improvement in his health and quality of life I mean. Seems entirely above-board, though. Fascinating.)
