
The power of intermittent fasting - technology
http://www.bbc.co.uk/news/health-19112549
======
reasonattlm
The interesting thing about intermittent fasting is that it seems to work
through a different but overlapping set of molecular mechanisms to calorie
restriction. The gene expression profiles in rodents say that the way in which
intermittent fasting (such as alternate day fasting, the most commonly studied
mode) works to alter metabolism into a better running state is not quite the
same as the mechanisms of straight calorie restriction.

[http://www.fightaging.org/archives/2010/05/intermittent-
fast...](http://www.fightaging.org/archives/2010/05/intermittent-fasting-with-
or-without-calorie-restriction.php)

[http://www.fightaging.org/archives/2009/11/a-little-
intermit...](http://www.fightaging.org/archives/2009/11/a-little-intermittent-
fasting-research.php)

So evidently you still have upregulated autophagy (i.e. better housekeeping in
cells), the levels of methionine in the diet are going to be lower thus
triggering that important switch in the metabolism of calorie restriction,
more ghrelin floating around to stimulate the immune system, and so on. But
it's not running the same way as for a steady low diet, and that appears to
make some differences. Intermittent fasting is not as well studied as calorie
restriction, but it is shown to extend life in mammals, and it is certainly
easier to manage for most humans:

[http://www.fightaging.org/archives/2009/02/practicing-
interm...](http://www.fightaging.org/archives/2009/02/practicing-intermittent-
fasting-versus-calorie-restriction.php)

Which means to say that you'll probably obtain health benefits by doing it,
but the studies that show massive health gains and enormously lowered risk of
age-related disease for calorie restricted humans may or may not apply to you.

~~~
DaniFong
Great point; I've been thinking about this for some time. Would love to have
more data, though! I'm also interested in any metabolic similarity either
influence has to endurance athletics.

~~~
reasonattlm
Exercise and calorie restriction both influence autophagy. In fact pretty much
everything that extends life in laboratory animals boosts autophagy one way or
another - such as through altered expression levels of heat shock proteins and
related regulators. You'll find that foundational study on exercise mimetic
drugs looks at heat shock protein manipulation more often than not.

[http://www.fightaging.org/archives/2012/01/testing-
autophagy...](http://www.fightaging.org/archives/2012/01/testing-autophagy-as-
a-mechanism-of-longevity-for-exercise.php)

[http://www.fightaging.org/archives/2009/09/heat-shock-
protei...](http://www.fightaging.org/archives/2009/09/heat-shock-proteins-and-
exercise-in-humans.php)

[http://www.fightaging.org/archives/2008/03/all-roads-lead-
to...](http://www.fightaging.org/archives/2008/03/all-roads-lead-to-
autophagy.php)

There is no consensus on whether different types of aerobic exercise are
better or worse for longevity, or whether more than the modest 30 minutes a
day is better or worse for longevity. Elite athletes have a massive longevity
advantage over the rest of the population, for example, but that can just as
well be explained by the fact that you have to be robust to become an elite
athlete in the first place.

[http://www.fightaging.org/archives/2011/05/putting-upper-
bou...](http://www.fightaging.org/archives/2011/05/putting-upper-bounds-on-
longevity-derived-from-exercise.php)

Exercise also works through hormesis and reactive oxygen species signaling -
which is why flooding your system with ingested antioxidants can destroy some
of its benefits:

[http://www.fightaging.org/archives/2009/05/exercise-
reactive...](http://www.fightaging.org/archives/2009/05/exercise-reactive-
oxygen-species-and-antioxidants.php)

~~~
DaniFong
Where are you based? Would love to host you, Cynthia Kenyon, and my friend
Laura Deming for a dinner on aging research.

~~~
DaniFong
We do weekly salons here: thesprouts.com

------
jacques_chester
Intermittent fasting works for me: <http://chester.id.au/2012/04/17/my-diet/>

I love food. I love everything about it. I love the smell of it, the sight of
it, the way steam rises of freshly cooked food. I love mixing it up. I love
the act of chewing, the taste, the way it feels in my mouth. The act of
swallowing is great and the sensation of fullness is sensational.

So it should come as no surprise that for _me_ , at least, weight control
through portion control has been an absolute failure.

What has worked for me is skipping meals altogether. If I don't start eating
at a given meal time I don't have to stop.

These days I skip breakfast, have a simple meal-replacement of my own recipe
at lunch, train in the afternoon and eat whatever I feel like at dinner. So
far I am 24kg (~53lb) down from my peak weight and the trendline is still
pointing down.

(I wrote about that, too: <http://chester.id.au/2012/05/26/fat-and-simple/>
\-- it caused one hell of a ruckus)

But do you know why? It isn't the schedule that really matters. It's that I
imposed a caloric deficit in a way that I personally am I able to sustain. For
others it might be low-carb or eating every 4 hours or being a vegetarian.
Whatever. At the end of the forcing function of weight control is how much you
ate.

Once I reach a weight I'm happy with I'll probably just eat an ordinary lunch
more often.

~~~
backprojection
>But do you know why? It isn't the schedule that really matters.

You haven't shown that. Where's the randomized experiment where one group is
assigned to eat 3000 cal/day evenly distributed, and the other group is
assigned 6000 cal during an 8 hour window, every other day, and then the same
thing but now 1800 cal per day, or 3600 every other day?

I don't fully understand this compulsion to explain anything successful in the
weight-loss field, ultimatlely, in terms of calorie restriction.

~~~
jacques_chester
> I don't fully understand this compulsion to explain anything successful in
> the weight-loss field, ultimatlely, in terms of calorie restriction.

Because any other hypothesis has to explain why it violates the conservation
of energy and matter. (Also: such studies are harder than they look to
arrange. Completely controlling someone's caloric intake and output is
difficult to achieve).

What tends to happen in discussions such as these is that they devolve into a
shouting match about the boundaries of causality. In a basic physical sense,
caloric balance is the only thing that matters. It is the causal element. Cut
calories enough, you will lose weight. Raise them enough, you will gain. The
relationship won't be linear, immediate, proportional or unary. But it _will_
be causal.

 _But that's oversimplifying!_ comes the cry. And it is. The internal
mechanisms of the body mediate and modulate weight control in interesting
ways. The ever-plunging $:calorie ratio has its input. And so on and so forth,
_ad infinitum_.

Proponents of IF talk about various interesting biological pathways that turn
on and off, hormone levels that change and so on. But the direct cause of
weight loss in IF is that you simply do not eat as much. You can't, you've
removed entire culturally-important, structured opportunities to eat. Gone,
just like that.

~~~
backprojection
> Because any other hypothesis has to explain why it violates the conservation
> of energy and matter.

This comment is so infuriating. I may not be a genius, but I did manage to eek
out a degree in physics. I think I, and anyone here on HN should be given the
benefit of the doubt that they can figurer out if energy conservation is being
violated.

Simply from a principle of assuming that the person suggesting the hypothesis
is not an _idiot_, you could infer that any of these alternative hypotheses do
_not _ violate energy conservation.

~~~
jacques_chester
I have found myself arguing with people who took the view that the
conservation of energy and matter does not apply to sufficiently complex
biological systems.

I am quite serious.

------
stevenkovar
Check out Martin Berkhan's <http://leangains.com> for more about making muscle
gains while fasting. There's a subtle difference between using fasting as a
tool for weight loss and one for body fat loss, but it's a difference
nonetheless—it largely boils down to better management of your macro-nutrients
(proteins, fats, carbohydrates) versus "eating like normal" after a fasting
period.

The most basic explanation is that you can fast whichever periods you would
like (most do 16 hour fasts + 8 hour "feeding windows"), but you must:

    
    
      A) Lift weights no more than 3 days a week
      B) Lift heavy weights to stimulate muscle growth
      C) Eat more carbs / less fats on workout days (more calories)
      D) Eat more fats / less carbs on "rest" days (less calories)
    

Compared to most lifestyles (this isn't a diet) this takes a lot of mental
preparation and calculation, so it is more daunting initially and less
mentally draining as you go on and see results (as compared to a fad diet
which is simple to implement but impossible to maintain). It's not easy but,
once a routine is established and the learning curve is overcome, many people
make the decision to keep the 'LeanGains' lifestyle for the remainder of their
lives.

~~~
graeme
I've been doing this for two months, works great for me. I'm down six pounds,
and ~%40 stronger. And I was already fairly lean.

------
saljam
In addition to fasting on the month of Ramadan, Muslims are “recommended”
(i.e. it's considered virtuous but not obligatory) to fast on Mondays and
Thursdays of every week. That sounds eerily similar to the 5:2 diet in the
article. <http://en.wikipedia.org/wiki/Sawm#Days_for_voluntary_fasting>

Muslims also know what's called prophet David's fasting, which is to fast
every other day. However, considering that includes water, it's considerably
difficult to maintain. I'm not sure I heard of anyone other than David himself
do it for a long period of time!
<http://en.wikipedia.org/wiki/Islamic_view_of_David>

~~~
Lost_BiomedE
A lot of the scientific interest in IF started with studying Muslims during
Ramadan. I assume that is why it is similar.

------
DanI-S
Am I the only person who becomes extremely irritable once their blood sugar
gets low? I can't imagine fasting for a day - I'd have no friends left by the
end of it.

~~~
pmjordan
Are you sure your blood sugar level really is low (hypoglycaemia), that is,
have you had it measured? Idiopathic postprandial syndrome is apparently much
more common, presents similar symptoms except blood glucose levels aren't
actually especially low and unlike hypoglycaemia, it does not appear to be
dangerous (unless you're driving and it interferes with your concentration).

If you suffer from actual hypoglycaemia, I would not recommend leaving it
untreated.

In the case of idiopathic postprandial syndrome, episodes seem to be brought
on by the steep decline back to _normal_ blood sugar levels, as opposed to
actual lack of glucose. What this means is you can avoid the problem by not
consuming sugary food and drink in the first place, or combining them with
other, non-sugary foods. Basically, don't let your glucose levels get so high
in the first place. Fasting for a day shouldn't bring on an episode (although
you'll certainly be very hungry!) - eating sugary foods, _then_ fasting, will,
however.

Of course, YMMV and I'm not a doctor or even a nutritionist.

~~~
johnthedebs
Thanks for posting this! I've had this problem for a while and was convinced I
was hypoglycemic but when I measured my blood sugar level, even at the peak of
the symptoms, it was always perfectly normal. I had the blood glucose meter
(and paranoia) because my sister is diabetic and I was afraid I might be too.
It's somehow very comforting to be able to put a label on this and to know
that it's not uncommon and (presumably) not dangerous.

------
latch
I've started to fast for a 24 hour period once a week (lunch on monday is my
last meal until lunch on tuesday). I drink tea and water. I'll break my fast
early if I have any signs of feeling unwell.

I haven't noticed any changes, but I was already in good shape, slept well,
and what not.

I'm not sure I buy the health benefits for people who are already healthy. I
tend to favor going by what the experts say, and overwhelmingly they say to
eat normally every day. The more progressive might admit that there's value in
further study.

On a different note... A couple years ago (long before I started fasting), I
was in a meeting and I got super hungry. It was painful. I realized that many
people live with this daily for decades. I think going hungry for a short
period of time might make some people more empathetic.

~~~
beagle3
> I tend to favor going by what the experts say, and overwhelmingly they say
> to eat normally every day. The more progressive might admit that there's
> value in further study.

I tend to follow experts when I don't have time to do my own research. But
when I do, I find -- very often, with nutrition advice, and too often for
comfort with medical advice -- that there's actually no scientific basis for
these recommendations; rather that they are somewhere between "leap of faith"
(that is sometimes provably wrong), superstition, and "that's the way we've
been doing for a while so we assume it's the right way".

For example, many experts still insist that you should limit egg yolk
consumption to no more than a few a week, although there's no science behind
it - just a 60 year hypothesis that's been repeatedly disproved over the last
30 years (although the belief is so strong almost no one seems to be aware of
those results).

And many still insist that the more cushioning for your ankle on your shoe the
better - although there was never any research indicating that this should be
true, and there is very consistent evidence showing that it is in fact
harmful.

> On a different note... A couple years ago (long before I started fasting), I
> was in a meeting and I got super hungry. It was painful. I realized that
> many people live with this daily for decades. I think going hungry for a
> short period of time might make some people more empathetic.

I had fasted for 21 days once, and did not feel any discomfort throughout (on
the contrary - up until day 14 or so, I felt disgusted at the thought of food;
after that, it just wasn't appealing). And then I felt hunger. Which is
something _completely_ different from appetite, which is what I referred to as
hunger before.

hunger is something that I've only ever felt at the end of the fast, and at
the end of an army training camp that didn't provide enough food -- and I
assume most people in the western world never do (although you might have - I
can't really tell).

It's not pain. It's an obsession with food that will not go away when you do
something interesting, which is unlike food craving or appetite - but I can't
really put it into words.

~~~
mgcross
Just a personal aside on the egg yolks - When I was 20lbs overweight, my
cholesterol was a little above 200. I've since lost weight and eat 4 whole
eggs for breakfast, and my cholesterol stays around 130, unfasted. I'm careful
when it comes to simple carbs but don't avoid red meat as much as I should,
given my genetics.

------
Swizec
It took me long enough to get used to eating every 3 to 4 hours. Now _this_?

Come on nutritionists, where was this theory when I was in high school and
would randomly go for two days without eating ...

PS: eating every 3 to 4 hours has brought the biggest gains to my leanness of
everything I've tried. Even better than running every day.

~~~
icegreentea
There is no contradiction between eating every 3-4 hours and intermittent
fasting. They occur on different time scales, you're going to be ok.

The big thing about intermittent fasting is that the rest of your diet has to
be 'normal' as well. If you were like me in highschool, my 'intermittent'
fasts were broken by... not optimal food choices.

------
Axsuul
I've also been doing this for awhile now. The program I'm on is called
LeanGains <http://www.leangains.com/> and I've been pretty successful with it.
I've went from about 15% BF to 10% with minimal muscle loss.

------
pgrote
ADF is the unknown secret to solving many modern ills ... or so I think. :)

I've had many conversations with three doctors about it and my thought is our
bodies haven't caught up evolutionary wise to eating each and every day.

I have no proof outside of personal results, which I understand doesn't make
it a reality. I could be a freak. lol

They key is not eating at all for a full 24 hours including your sleep cycle
and then to only eat a normal meal on the days you eat.

~~~
ams6110
I think this is actually very likely to be true. Think about living as a
hunter-gatherer. Some days you just won't find/catch anything. Maybe you snack
on a few insects. Other days you bag an antelope or find a big patch of
berries and you have more than you can eat. Alternating between fast and feast
every few days seems like it would be quite common. Eating a regular 3 meals a
day is probably not the norm.

~~~
DenisM

      So, two prehistoric men discuss cooking:
      - cooking meat should make you live longer
      - I don't know, man, my father always ate raw meat
        and he lived without any problems all the way
        till the old age of twenty one!
    

My point being, just because it's the old way, doesn't mean it's the better
way.

~~~
dpn
The obvious counter to that argument is that people didn't die of obesity, we
didn't have antibiotics yet. :)

------
sandGorgon
The article is not very clear behind the science of intermittent fasting - for
those who are interested, do definitely read Alan Aragon's article [1] as well
as /r/advancedfitness.

My personal view is that meal frequency is irrelevant for body biochemistry.
What is happening is CNS (central nervous sytem) Adaptation - you are, for the
first time, truly understanding how _really_ hungry you are. Your body begins
to understand that it does NOT need to eat breakfast, or eat something every 4
hours or eat a dozen nachos as an evening snack. When this happens, you
automatically balance out on calories in vs calories out and you start losing
weight.

I think this is a workaround for a bug in our brain - it makes pessimistic
predictions for food availability and hunger responses.

[1] [http://www.alanaragon.com/an-objective-look-at-
intermittent-...](http://www.alanaragon.com/an-objective-look-at-intermittent-
fasting.html)

~~~
Swizec
I would wager this depends a lot on the type of activity you're doing.

Sometimes after a really hard boxing practice I can be so hungry that I
physically can't eat any more food, but I'm still hungry. And no, it isn't
just a bug in the brain, the calorie tracker also agrees that I haven't eaten
enough.

~~~
beagle3
> Sometimes after a really hard boxing practice I can be so hungry that I
> physically can't eat any more food, but I'm still hungry.

For me it is the complete opposite - I can't eat or even think of food for a
while, and am definitely not hungry or have any appetite -- and the harder the
practice is, the longer it takes appetite to recover. (My practice of choice
is thai boxing, btw...)

~~~
Swizec
This is usually an hour after practice. Takes a while to get home, take a
shower, prepare the food etc.

------
rickdale
This advice is sort of along the same lines as the Warrior Diet which preaches
fasting all day and preserving yourself for one large prepared meal to quench
your warrior instinct. I follow the Warrior Diet 3-5 days/week. It recommends
eating vegetables during the fast (some lean proteins if you workout a lot)
and also ways to start your one big meal. The diet plan instructs you to eat
some vegetables first followed by protein and then grain.

I really like this diet, but it is difficult to follow everyday. I would say I
have 2 cheat days/week where I eat a lot of junk food. This summer ice cream
has been my haven. All in all I am down 40lbs since the beginning of this
year... Should mention and thank the slow carb diet for at least 30 of those
lbs... (note:slow carb diet is eating every 4 hours....)

------
pakitan
I see people here mostly talk about effects fasting has on health but not much
about effects on mental/physical performance. If you live longer but you're
less effective in what you do, fasting turns into a much less attractive
choice, at least for some people.

From my very non-scientific experiments, I can tell that my bullet (1 min)
chess rating suffers a lot when I'm restricting my calories. It's really hard
to measure how fasting would affect a more complex activity, like
programming...probably the impact is smaller but there certainly is an impact.
With restricted calories, I usually need to add caffeine to the mix to
suppress my hunger and make it easier to concentrate.

~~~
dpn
I tend to be a lot more productive when fasting.

I also tend to be more impulsive, so staying focused on the thing I should be
doing, as opposed to what I want to do, is definitely an issue.

That being said, the time I save by not eating breakfast is also nice :)

------
harscoat
Here you can rate if those "fasting" methods/lifehacks works or not:
<https://didthis-actionwiki.appspot.com/tag/fasting>

To create new ones: <https://didthis-actionwiki.appspot.com/create>, or fork
those already in eg. [https://didthis-
actionwiki.appspot.com/intermittent%20fastin...](https://didthis-
actionwiki.appspot.com/intermittent%20fasting/copy) (just add "/copy" at the
end of the action link).

------
StavrosK
I've practiced inttermittent fasting for a bit (eating absolutely nothing with
calories one day a week), and, apart from losing weight (which I can't
attribute entirely to IF, since I was also eating less in general, but IF
definitely helped), it was just more convenient for me.

I prefer to just eat nothing one day, which is relatively easy since I work/do
stuff during the day and have to take time out of the day to eat, and then
indulge the rest of the week. IF enabled me both to not keep in mind how much
I eat six days out of the week, and to just simply not eat anything for one
day. I consider it a great success.

------
mgcross
I've got a friend who has been on something akin to the warrior diet without
knowing it. He works as a server, so He's up all night and sleeps during the
day with one grand, large meal he eats in the afternoon. He did it more as a
convenience than anything, but has lost about 20lbs in the past few months. I
normally eat every few hours, but may try this out as long as it doesn't
adversely impact my work or exercise regime.

------
Supermighty
I saw that other article about fasting and decided to give it a try yesterday.
I made it about six hours before I realized my concentration was way off and
my emotional balance was out of whack.

Granted I was also working a freelance job. Which in retrospective was
probably a bad idea. However I did learn something about myself. And next time
I try fasting I'll make sure that I don't have anything pressing due the same
day.

------
BlackJack
A big thing to stress here is that you _eat normally the other days_. I know
some people who have tried IF who gorge on food once the fast ends, and end up
no better off than not fasting at all - calorie wise at least.

~~~
gwern
That's good advice if you want to lose weight, but a number of IF studies were
calorie neutral (double rations on non-fast days) and that's why I find it
interesting: it's triggering some of the same benefits as CR but _without_
restricting calories, which means it may be a much easier lifestyle to
maintain.

------
amirmansour
Right now is the month of Ramadan.

------
maeon3
Fast too much and your body goes into famine mode, where your fat storage
management system is convinced that this month's food catch is low, and it is
likely this will be a lean year. Therefore store everything you can to fat and
keep energy outputs low. Causing obesity.

When I was 26 ish, i fasted for 3 days. I'm 30 now. Dumbest thing i ever did.
I gained weight from that DAY I started eating again forward, and it's been a
battle of the buldge ever since.

~~~
sandGorgon
There have been many, many papers that show that starvation mode does not kick
in until after about 36-48 hours of fasting. Intermittent fasting is usually a
16-24 hour fast.

~~~
jamiecurle
For those interesting in the papers [Leangains][0] has a long informative
narrative connecting the papers together.

[0]: [http://www.leangains.com/2010/10/top-ten-fasting-myths-
debun...](http://www.leangains.com/2010/10/top-ten-fasting-myths-
debunked.html)

