
Alternate Day Fasting Improves Physiological and Molecular Markers of Aging [pdf] - Tomte
https://www.cell.com/action/showPdf?pii=S1550-4131%2819%2930429-2
======
dvt
I fast, on average, once a week. At least once a month, I try to do an
extended fast (2-5 days) to force ketosis. I also do intermittent fasting
basically daily (I only eat between 12-8). Been doing this for about 4 years
now. Some anecdata:

\- Fasting > 24 hrs paradoxically gives you an extreme boost of energy and
mental focus. I especially love how my olfactory sense is _extremely_
heightened. It's pretty cool and even after all these years doesn't get old.

\- Fasting is not a panacea. Depriving yourself of nutrients or eating garbage
is still a bad idea even if you fast or do IF. Unfortunately, eating healthy
is hard and kinda' sucks. Egg whites and chicken + broccoli gets old pretty
fast.

\- Fasting >7 days is a bad idea unless you know what you're doing. This is
when your muscles and vital organs start contributing as an energy source
(e.g. they also start breaking down).

\- Your body is clever, so extended fasts will start putting you into
"starvation mode" and you'll lose some of the benefits.

\- There have been NO STUDIES on long-term fasting (e.g. over the course of an
adult lifetime). This is a big warning sign to just be careful and not overdo
it. Different people have different tolerances. Talk to your doctor.

\- Even on fast days, make sure you take vitamins (I take Fish Oil, Zinc, a
Multivitamin and Magnesium)

~~~
kace91
Are you fit? as in, do you lift weights or are active in sports that require
strength?

I ask because I wonder about the effects of extended fasts on muscle
loss/retention, a big problem cutting weight for some people is that they get
rid of some muscle mass along with the calories they wanted to eliminate.

~~~
dvt
I did for a few months this year, but I've been lazy over the summer. I'm
155lb, 6'0, so fairly skinny, maybe at around ~15% BF. I noticed that fasting
doesn't help with BF at all unless I eat very clean and lift. I was at 170lb,
around ~28% BF earlier this year and had to work my ass off to get my body fat
percentage down.

~~~
SketchySeaBeast
> I noticed that fasting doesn't help with BF at all unless I eat very clean
> and lift.

So what happens? You lose muscle and fat in the same ratio? Or do you keep the
fat?

~~~
dvt
I feel that my body kind of adjusts to the fasting and I just don't lose much
of anything.

~~~
SketchySeaBeast
That sounds to me like "I eat more to make up the calories when I'm not
fasting".

------
all_blue_chucks
This fasting caused a 37.4% reduction in caloric intake. It raises the
question of whether it was the fasting itself or merely the overall caloric
reduction that made the real difference.

~~~
davinic
I wondered this as well. In many of the intermittent fasting studies they kept
caloric intake the same and showed that the benefits applied even when taking
caloric restriction out of the equation.

~~~
rtkwe
A lot of diets, especially IF style diets, are pretty much just tricks to get
you to eat less calorie wise. Intermittent fasting does this by just setting
the simple rule, only eat during a relatively small window of time. It's
easier to eat less during that period because there's only so much you can
comfortably eat in that time. (Granted you can totally fit a whole day's
intake in the IF period but it's harder).

~~~
frank_nitti
Is there really no difference between eating 1500 calories at once vs. over
the course of 5 meals?

Of course, there is no weight loss without a calorie deficit, but are all
calorie deficits equivalent on magnitude alone? I struggle with the notion
that the timing does not matter at all, and much of the suggested benefits of
controlling the timing focus on other metrics beside immediate weight loss.

The "wisdom" of the late 90s was that six or so small meals were better than
one large meal, with respect to weight loss. Now it appears some experts would
argue the opposite. Is it all just a bunch of smoke and mirrors over calories
in > calories out?

~~~
rsync
"Is there really no difference between eating 1500 calories at once vs. over
the course of 5 meals?"

Digestion - and the ramping up of your entire metabolic process - is not a
minor task. It is an all-hands-on-deck marshaling of a number of bodily
processes that preclude other processes that you might like your body to
engage in.

If you are firing up this mechanism every three hours - insulin response,
spiking your blood sugar, moving your stomach and bowels, etc., then you never
give your body time to do any other housekeeping tasks.

Think of food intake as an _interrupt_ , in computer science parlance. What
happens to process performance when you're throwing interrupts ?

IANAD.

~~~
SketchySeaBeast
> then you never give your body time to do any other housekeeping tasks.

Do you have any links to describe what other tasks it would want to be doing
in that time and which are blocked by an insulin spike?

~~~
rsync
[https://osher.ucsf.edu/patient-care/integrative-medicine-
res...](https://osher.ucsf.edu/patient-care/integrative-medicine-
resources/cancer-and-nutrition/faq/cancer-and-fasting-calorie-restriction)

"...it is theorized that cancer cells do not respond to the protective signals
generated by fasting, thus leaving them vulnerable to both the immune system
and cancer treatment. This process is known as differential stress resistance
(DSR). Short-term starvation (STS), fasting for 48 hours, causes a rapid
switch of cells to a protected mode, which is capable of protecting mammalian
cells and mice from various toxins, including chemotherapy."

(et. al)

I read it as cleanup/housekeeping tasks that aren't high priority, relative to
processing food inputs. When freed from those tasks, the body can concentrate
on housekeeping.

~~~
SketchySeaBeast
That's not housekeeping though, that's in the case of fighting cancer. And
based upon the mechanism you lay out, that's with outside intervention. That
doesn't seem to expand out to "general housekeeping" when you're also dealing
with medical science trying to kill cancer without killing you.

------
dmd149
Been doing intermittent fasting for a long time now and have been doing ADF
for the last few months.

I lost fat and retained lean muscle while \- eating between 3000-6000 calories
on eating days \- running 30-35 miles per week \- weight lifting 3x per week

Here is a reddit post about my progress with some documentation including pics
of recent DEXA scans.

[https://www.reddit.com/r/leangains/comments/cliuqk/been_prac...](https://www.reddit.com/r/leangains/comments/cliuqk/been_practicing_alternate_day_fasting_for_about_6/)

~~~
nradov
Congratulations on your accomplishments. Can I ask how you manage to choke
down 6000 kcal on eating days? Even when I'm really hungry I can't physically
force myself to eat that much. It makes me feel sick and my digestive system
is at the limit.

~~~
dmd149
I’m one of those people that eat quickly and a lot, so I’ve just become
accustomed to eating big meals.

That being said, I also eat significant amounts of junk food. Slice of cake is
like 500-800 calories. No problem. I can do that x 3 after a meal of normal
stuff. Junk is easy to throw down and calorie dense. Also, its fun to eat.

Now 6000 calories of salad and lean meats? That would be difficult...

------
goda90
>For healthy, non-obese adults, ADF is safe to practice for several months

They might just be saying this because they didn't test any further, but does
anyone know any reasons why it might stop being safe after several months?

~~~
moltar
IMO it’s not unsafe. The longest supervised fast was a whole year long. The
person was obese and only supplemented vitamins if I remember correctly.

Fasting is how we evolved to eat. We didn’t have Costco and fridges 10k years
ago.

~~~
javagram
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2495396/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2495396/)

Note, however, he died relatively young although he did live a few decades
after the fast
[https://en.m.wikipedia.org/wiki/Angus_Barbieri%27s_fast](https://en.m.wikipedia.org/wiki/Angus_Barbieri%27s_fast)

------
chiefalchemist
Sample size was small for the ADFs (approx 40). They were compared to control
of 60. I didn't drill deep enough to see age and/or gender breakdown.

That said, fasting as pro-health tool keeps coming up and the gist time and
again seems to say it yields a positive.

------
ciconia
We have neighbours with twins aged 7 who raise their kids at home on a raw
food diet. They eat lots of nuts, fresh fruit, fermented beans and garden
vegetables. They conserve vegetables and fruit using lacto-fermentation.

The kids are much smaller and thinner than normal kids their age. Up until
recently I used to pity these _poor, starving_ kids. I compared them to our
kids, who are athletic, tanned, well built.

But recently I started asking myself if this is not the other way around.
Maybe if we didn't have the luxury of cooking, transformed food and western
supermarkets we'd have been much smaller. Maybe this means that we _all_ in
the 1st world eat too much.

I'm starting to think that maybe we're not really better off having our
stomachs full basically the whole day long, especially if you consider that
most of us do very little physical activity if at all...

~~~
nathell
Hey ciconia, I wanted to drop you an email on an unrelated note, but was
unable to find contact info. So please check out this comment:
[https://news.ycombinator.com/item?id=20852873](https://news.ycombinator.com/item?id=20852873)

(Other readers, please accept my apologies for hijacking the subthread.)

------
proc0
I've been fasting weekly for a long time (after starting with intermittent
fasting). I'm glad to see an article like this because I've been waiting to
try fasting every other day. My subjective observation is that there is a
misconception of what the body does with nutrients and that is why in general
people won't think of even trying to fast ever.

To use contrasting analogies, it seems in general the perception is that the
body works like a car and you have to re-fuel it every few hours in order to
keep going. However, from my experience I think the body is more like a
factory that creates its own energy. It needs materials, from which a part is
used for energy, but thanks to having storage, you have plenty of supplies to
keep going until the next shipment of resources arrive. In other words, fuel
is burned in proportion to the user of the car, but factories don't
necessarily use their materials as soon as it receives the shipment. Factories
can store resources and their use is scheduled for a later use.

Therefore it is better to optimize for quality of materials, rather than
frequency of consumption! Your body will use the materials it gathered from
the past few days of consuming food (no citation here, but again just my
experience), and the only problem of not eating is the BRAIN's expectation of
eating food every day and that feeling of satiation, which is basically a hit
of dopamine and not a true sign of wether you need materials and/or energy to
survive.

------
eduardothomas28
Be careful If you are going to try fasting. If you read carefully, fasting
increases PUFAs on the serum and if you have plenty of PUFAs in your body, it
could kill your thyroid and metabolism.

Before trying fasting be sure to have at least a month of healthy eating and
try sipping unsweetened lemon juice while you fast.

------
donclark
Here is a different link -
[https://link.springer.com/article/10.1007/s12325-018-0746-5](https://link.springer.com/article/10.1007/s12325-018-0746-5)

~~~
ejstronge
This is a different article altogether (which may be what you mean).

Here's a link to a webpage for the OP article:
[https://www.sciencedirect.com/science/article/abs/pii/S15504...](https://www.sciencedirect.com/science/article/abs/pii/S1550413119304292?via%3Dihub)

------
mark_l_watson
I am happy to see another study that indicates good results.

I have stopped fasting, even though I believe in the benefits.

Now, I just make sure that every day I have at least a 12 hour contiguous
period of not eating. This is really easy to do, for example, finishing dinner
by 6:30pm and not eating until 7:30am the next day gives me a 13 hour period
for resting my digestive system and giving my cells some time to repair rather
than absorb nutrients. Easy, and with a mostly vegan diet except with lean
meat about two times a week, I feel great.

For me, it is best to stay on an easy program, something that I can do long
term.

------
tempsy
I was heading to the gym near the Twitter HQ in SF yesterday and saw Jack
Dorsey walk past. He looked extremely thin and borderline sick to me. I think
he does more extended fasts over the weekend but it’s a bit unnerving when
someone in a position to influence behavior like he is seems to be taking
fasting to an extreme.

~~~
SwellJoe
I've seen a lot of people say stuff like this, but it's kinda gross. If you
want to criticize things someone has said about their diet and health
practices, that's fine (and hopefully, you'll cite sources for why they're
wrong), but if you're going to make it about how they look, and make your own
diagnosis about their health, that's not really OK.

You don't know anything about the guy's health. He may actually be sick,
wholly unrelated to his diet. He could be dealing with an eating disorder
(which may be related to his diet, but millions of people have fasted
regularly without having an eating disorder...there are lots of ways people
cover for eating disorders). And, maybe he's in great health and your beliefs
about what "healthy" looks like are wrong ("put some meat on your bones" is
not great health advice for most people, but it's a common refrain).

I don't really know anything about what he's said about diet or fasting. But,
I know that bringing his appearance and health into it are not shedding light
on the subject, they're just conflating appearance with health and well-being
in ways that aren't useful.

~~~
core-questions
> that's not really OK.

This kind of word policing is even less OK. It's not "gross" to make a comment
about something you see and have opinions about, especially for a public
figure. You're not shedding light on any subject, either, all you're doing is
being offended-on-behalf of someone else; the world's got enough of that and
it doesn't seem to be making any positive difference at all.

~~~
SwellJoe
The comment I responded to did not add substantively to the discussion, and I
pointed out why.

I am not "policing" anything. I have no power to arrest someone or censor
someone for being an asshole online. I expressed an opinion about the kind of
community I'd like to be a part of. Also, it seems like you're doing what
you're criticizing me for. I _don 't_ think the world's got enough of minding
one's own damned business regarding people's health, body, and appearance, and
that having more of it _would_ make a positive difference. This conversation
is about the science of fasting, not whether Jack Dorsey looks thin.

~~~
core-questions
> Also, it seems like you're doing what you're criticizing me for.

Sure, but only in a meta-sense to curb the proliferation of the technique. I'd
liken it to nuking would-be nuclear powers to prevent further problems.

And maybe, _just maybe_, Jack Dorsey should eat a sandwich.

~~~
SwellJoe
> I'd liken it to nuking would-be nuclear powers to prevent further problems.

So, when you wrote this, did the idea of using nuclear weapons preemptively
seem like an obviously good idea, to you?

------
crimsonalucard
If I eat two meals in one sitting and then wait 23 hours before my next meal
is this a form of intermittent fasting? I still get the same amount of
calories as a normal person but there's a long period where I get nothing.

(I've been skipping breakfast my entire life so I don't really get the 3 meal
thing.)

~~~
jobigoud
Yes, it's known as 23:1 Intermittent Fasting or more commonly OMAD, one meal a
day.

~~~
crimsonalucard
Is it? The thing is I'm eating two meals in one sitting so it's still two
meals a day. I typically thought intermittent fasting meant one meal per day.
Does what I'm doing still count?

~~~
jobigoud
I think the amount of food doesn't matter, I would say if it's in one sitting
it count as one meal. People that do OMAD usually eat much more than what they
would eat in a normal meal, otherwise it wouldn't be sustainable in the long
term.

Intermittent Fasting just means there is a 12+ hour period between the last
meal of the day and the first meal of the next day. The most typical form is
two meals a day in 16:8 fashion.

------
collyw
Is this new knowledge?

It sounds pretty similar to what was discovered in BBC's "Eat Fast Live
longer" and that's a good few years old.

[https://vimeo.com/259080453](https://vimeo.com/259080453)

------
ubermonkey
It's interesting, but as a hobby and primary physical outlet I'm very involved
in cycling. I don't race, but I ride with racers, and keep up.

I do not think I could balance fasting with 1,500 calorie efforts. ;)

~~~
kasey_junk
Funny enough in the 70s and 80s (and into the early 90s in some rare cases) it
was fairly common for cyclists to cut weight like boxers.

I think its fair to assume that caffeine and amphetamines were used to achieve
those results and not strict fasting regimes...

~~~
ubermonkey
Sure. I think that's still done -- I mean, look at top-tier racers.

But fasting and cutting weight are different ideas.

~~~
kasey_junk
I just meant that cutting calories while cycle training has a long history
(though I would describe it as healthy)

~~~
ubermonkey
Diet modification during training typically still involves eating more
calories than a sedentary person.

~~~
kasey_junk
I know less about cycling diets than I do fighter camps but it is incredibly
common for fighters to eat at fasting levels while continuing to train. The
strict weight requirements cause that.

I was of the impression that it used to be the case that cyclists did this but
that it was out of fashion now.

In any case lots of people do 1500 calorie efforts at fasting intake levels.
It’s not healthy long term but it’s completely ‘normal’ for done athletes.

------
gwern
Mirror:
[https://www.gwern.net/docs/longevity/2019-stekovic.pdf](https://www.gwern.net/docs/longevity/2019-stekovic.pdf)

------
plg
A -37% change in caloric intake (Fig. 2B) produces only a -4.5% change in body
mass (Fig. 3A)? Seems odd no? Or am I mis-reading something?

~~~
theothermkn
This change was reported over 4 weeks, or 28 days.

For a 180lb person consuming, on average, 1900 kCal/day, a 37% drop in
calories is a 703 kCal/day deficit below their initial equilibrium. This is
19,700 kCal over four weeks. Divided by 3600 kCal/lb, this is about 5.5 lbs.
4.5% of 180 lbs is 8.2 lbs. So, we're in the ball park. A 3-lb deficit from
reduced inflammation (water) seems reasonable.

For a higher initial weight, you can get the numbers to agree exactly. I'm 6'
and 182 lbs., which is just barely overweight. In the U.S., were I live, I
look pretty "fit" by comparison with the average person. (I'm not, but that's
another story.) According to [1], Austria, from where the participants were
likely sourced, is only slightly leaner than the United States.

Therefore, their numbers seem to line up. Westerners are stuffing themselves.

[1] [https://www.indexmundi.com/blog/wp-
content/uploads/2013/04/w...](https://www.indexmundi.com/blog/wp-
content/uploads/2013/04/weight-of-the-world.jpg)

------
travbrack
Does this increase risk of gallstones?

~~~
najarvg
Yes it does. See -
[https://news.ycombinator.com/item?id=20813736](https://news.ycombinator.com/item?id=20813736)

~~~
getpost
>..."might increase the risk of gallstone disease"...

I do 18:6 intermittent fasting and I did have a gallstone episode. My
intuition is that fasting precipitated the expulsion of stones that had formed
prior to the onset of my fasting regimen. Also, while practicing intermittent
fasting, I think I have a tendency to overeat during my main meal of the day,
maybe as a subconscious attempt to avoid feeling hungry later on. To avoid
overeating, I need to be mindful to stop eating while I still feel slightly
hungry.

The following blog post is consistent with my experience:
[https://gallstonesdiet.net/can-intermittent-fasting-cause-
ga...](https://gallstonesdiet.net/can-intermittent-fasting-cause-gallstones/)

~~~
jobigoud
> To avoid overeating, I need to be mindful to stop eating while I still feel
> slightly hungry

For me the trick is to eat really slowly, even if I'm hungry.

------
sbmthakur
Does fasting bring about any significant changes at the cellular level?

------
kasi
why is this dated Sept 3rd 2019 (the future)?

~~~
PeterWhittaker
They publish biweekly, this might be a pre-release from next week’s issue.

------
donclark
Add (PDF) to the tile please (looks like its a direct link to a PDF)

~~~
sctb
Updated. Thanks!

