
Flipping the Metabolic Switch: Applying the Health Benefits of Fasting - hourislate
https://onlinelibrary.wiley.com/doi/full/10.1002/oby.22065
======
kaslai
I've had serious weight issues for my whole life, primarily due to my love of
chocolate. As I approached 400 pounds, I took a hard look at myself and
decided to make a change. For the past month (29 days now) I've been doing
alternate-day fasting* where I eat about 2000-2500kcal on eat days and cap
myself at about 100kcal of half-and-half with coffee on fast days (gotta get
that joe).

While a lot of it is no doubt non-lipid mass (glycogen and such), I just
passed 30 pounds of mass lost yesterday. After the initial drop from glycogen
loss, I've been averaging 0.4-ish pounds a day of mass loss.

A few things I've noticed: What I eat doesn't really affect long-term weight
loss. Carbs will cause my weight to rise, but it's definitely just due to the
storage and retention of glycogen and water, as I get right back on track with
my projections 2-3 days later. However, if I eat carbs and fast the next day,
I will get serious hunger pangs. If I eat a mostly keto diet, then I can pass
between eat days and fast days with no trouble at all.

My biggest take-away though is that fasting has helped me practice self-denial
to the point where I can handle my sweet tooth very easily now. The difference
in apparent willpower is so immense that I can hardly believe it myself. I
definitely suggest that anyone who has self-control issues with regards to
food go on a week of alternate day fasting. Additionally, a fast day is a
great way to counter out a day of eating to excess. When I lose my weight,
I'll still keep fasting as an option, because it's a remarkably powerful tool.

* It's actually 3 days of fasting, 4 days of eating a week. I do social eating on Fridays and Sundays, so I keep those as fixed eat days, so I just fast on Sat/Mon/Wed, eat on Fri/Sun/Tue/Thu.

~~~
martin-adams
I just listened to The Obesity Code by Jason Fung and my mind is kinda blown.
Everyone you've said matches what the book covers.

The takeaway points are:

\- Raised insulin is the key driver in weight by preventing the burning of fat
and triggers the storage to fat. Insulin is the hormone that tells allows
cells to absorb glucose

\- Type 2 diabetes is caused by insulin resistance, which happens over years
of prolonged periods of raised insulin without periods of lowered insulin.
Carbohydrates and sugar convert to glucose, insulin resistance prevents it
being used by cells, triggering the ask for more glucose by those cells to be
available, by way of asking for more insulin. Raised insulin and glucose
contribute to more fat being stored.

\- The western lifestyle is based around eating evenly throughout the day
reducing our fasted state. This means our insulin levels don't have a chance
to lower.

\- Fasting is a way to give your body a break from raised insulin, use up the
glucose energy first, then switch to fat burning (Ketosis).

\- Sugars and carbohydrates do not trigger the hormone that says we're full
when compared.

If this is of interest to you, I highly recommend the book. I'm still learning
all the specifics so some of the above may be incorrect.

I very much plan to start reducing my sugar and carbohydrate intake and
introduce intermittent fasting.

~~~
pmccarren
> Sugars and carbohydrates do not trigger the hormone that says we're full
> when compared

It's important to note the difference between refined sugars (candy) and
natural sugars (fruits). Refined sugars are basically fructose (hello High
Fructose Corn Syrup).

Refined sugars -- super hella bad.

When you eat the refined sugars, your liver actually traps the ATP, blocking
the pathway to the brain, making you still feel hungry.

Great 10 min clip:
[https://www.youtube.com/watch?v=8ve6XQH68mg](https://www.youtube.com/watch?v=8ve6XQH68mg)

~~~
Isamu
> Refined sugars are basically fructose

sucrose (white refined sugar) is half fructose, half glucose

[https://en.wikipedia.org/wiki/Sucrose](https://en.wikipedia.org/wiki/Sucrose)

High Fructose Corn Syrup has a variable amount of fructose, but is usually
similar to cane sugar because it is used as a substitute.

[https://en.wikipedia.org/wiki/High-
fructose_corn_syrup](https://en.wikipedia.org/wiki/High-fructose_corn_syrup)

~~~
maxk42
HFCS is generally in the range of 50% to 90% fructose. In other words, it's
typically worse than sucrose for you.

Fructose does not provoke a satiety response in the human gastroenteric
system, unlike glucose.

So if you _do_ eat candy, prefer sucrose to HFCS and glucose to sucrose.
Sucrose will be listed on packaging as "sugar".

------
pmccarren
I highly recommend looking into the work of Dr. Rhonda Patrick, Ph.D. She has
extensive material explaining the science behind IF, and many other topics
relating to bio pathways and aging.

[https://www.youtube.com/watch?v=m6KClPkotxM](https://www.youtube.com/watch?v=m6KClPkotxM)

[https://www.foundmyfitness.com/](https://www.foundmyfitness.com/)

~~~
nissarup
And broccoli sprouts! Don't forget the broccoli sprouts!

Jesting aside. She is cool, talks very fast and deliver an awful lot of
information in a short time.

~~~
pmccarren
Hah gotta get that sulforaphane!

Though I do agree - her podcasts can sometimes be a bit of an information
overload for those who aren't biomed folk. However in my opinion, her youtube
channel[1] is significantly easier to follow as there are often animations and
more lengthly explanations.

[1]
[https://www.youtube.com/foundmyfitness](https://www.youtube.com/foundmyfitness)

------
JoshMnem
I've been experimenting with water fasting, intermittent fasting, and calorie
restriction for over two years with good results. I gradually went from an
"obese" BMI to normal, and reduced the symptoms of some medical conditions,
especially after 3-5 day water fasts.

I think that if one is going to restrict calories, it's a good idea to eat a
high-nutrient diet. Mine is _mostly_ vegan + fish, and based on vegetables,
legumes, nuts, seeds, and fruits. Almost zero sugar, low salt, no flour, and
not a lot of grains.

A saying that helped me stay focused is, "Food is not a recreational drug."

~~~
wmeredith
Please note: dry fasting is incredibly dangerous and one will struggle to find
non-crackpot sources that say humans should attempt it for any reason. Healthy
people can survive a month or more without food. Without food AND water they
last less than a handful of days.

~~~
samat
You might be surprised, but most Muslims do dry fasting each year on Ramadan
;)

------
throwaway413
Fitting to see this during this month, as it is currently the holy month of
Ramandan for Muslims, who fast from sunrise to sunset for 30 days.

~~~
baud147258
Well, perhaps it's good for the metabolism of my muslim colleague, but right
now his productivity is way down. Also I don't the ramandan fasting is
particularly good since muslims usually eat a lot during the night to
compensate.

~~~
jbm
I generally don’t have a problem at work (Ramadan + Keto). Then again I don’t
get up at 2 AM to eat. (Generally have a 18:6 fasting to eating cycle)

Can you share how you are measuring changes in his productivity? I find that,
in general, to be fairly difficult to measure, let alone find trends in small
time intervals (like a week)

------
virtuallynathan
I can 100% vouch for this, roughly 90 days ago I implemented:

* 16h+ intermittent fasting

* increased exercise (>600kcal Apple Watch active kcal)

* caloric restriction (average of 450kcal deficit).

I lost 20lbs in 90 days (5ft5in 145 -> 125). I've since gone to a full
ketogenic diet as an n=1 experiment.

I find the research on this lacking, but fascinating -- its been a very
educational experience. Based on the many papers I've read, and talks I've
listened to, it seems like society's current ailments of obesity, diabetes,
and heart disease (and maybe Alzheimers) tie back to excess carbohydrate
consumption leading to hyperinsulinemia.

Re: this paper -- they cite that "Mice fed a high‐fat diet ad libitum develop
obesity, elevated plasma glucose, insulin and leptin levels, and impaired
glucose tolerance" However, reading the source for that, the diet of those
mice was: "18% protein, 61% fat, 21% carbohydrates" \-- probably still too
many carbs.

~~~
wink
Not eating for 16h-18h is not intermittent fasting for me, but how I've lived
huge parts of my life. Lunch at noon or soon after, dinner before 8, nothing
else. Didn't notice anything remotely pointing towards losing weight to a
reasonable weight.

------
DanielBMarkham
Like many programmers, especially us older folks, I've struggled with my
weight my entire life.

Three weeks ago I went on a ketogenic diet. This week I've added intermittent
fasting, only eating between noon and six.

After the "keto flu" period ended, it's been quite enjoyable. The IF comes
quite naturally and is painless.

I'm not one to spot diet trends, but my intuition says that keto/IF will be a
big thing over the next few years. It feels like it's reached critical mass.

~~~
mnort
I'd be curious to hear more about what you experienced during your keto flu

~~~
jobu
For me it was very similar to the early stages of a bad flu. Tired, headaches,
body aches, irritable, and mild nausea for about 5 days. I've heard that MCT
oil can ease the transition a bit, but be careful because too much can cause
stomach cramps and violent diarrhea. (I've never been able to handle more than
one tablespoon at a time.)

~~~
virtuallynathan
Make sure you are getting enough sodium and potassium, its my understanding
that being in ketosis increases excretion.

------
Cthulhu_
12 hours? Sounds like just skipping breakfast would constitute as intermittent
fasting for me. My breakfast is usually pretty light anyway.

~~~
hudibras
You're exactly right. Just skip breakfast and don't eat snacks after dinner
and you'll be at 16 hours easy. Try it for a week and see how you feel.

I've been IF'ing for 15 months now and it's great. Lost 20 pounds without even
trying and have more energy during the day.

~~~
tozeur
Turns out I IF’d all throughout high school without even knowing it!

~~~
stefantheard
this was my realization too when I first started hearing about IF several
years back.. "I do this already, but on accident" I have never eaten breakfast
in my adult life. I eat once at 11:00AM for lunch, then again at either 6:00PM
or 9:00PM for dinner depending on if I train that night or not. I don't snack
or drink any calories, so this is basically intermittent fasting right? It
seems weird but it does make sense, I am relatively lean and don't put much
effort into it.

~~~
extr
I'm the same way. People always nag me to eat breakfast but that actually just
makes me hungrier and throws off my schedule. Generally if I don't eat
anything I won't get hungry for a few hours after waking up, until 11-11:30
like you. I'll have a "big" lunch, like chipotle burrito size, then a light
dinner 7-8 hours later. No snacking and stick to drinking water, black coffee,
and alcohol. I remain at the same weight I was in high school and haven't
fluctuated more than +/\- 5 pounds over my entire adult life. It honestly
rules and I don't even know how I got into this routine, just that eating
breakfast usually seems gross to me.

------
joshe
It would be cool to see measurements of people on Survivor or all the alone in
wild shows. Like blood glucose, ketones, movement tracking, and sleep. Maybe
even a few IQ and strength tests. There's all this great documentary
monitoring and doctors already on site. I assume that academic ethic review
boards would never allow a researcher to participate, but it would be great if
the shows shared it. Maybe the individual competitors could.

I wish there was some middle ground between self tracking and big expensive
studies that don't really change anything.

------
amelius
Sounds great, but is this compatible with:

\- bodybuilding

\- 20 miles daily commute by bicycle

\- intellectually intense work, e.g. hackathons

?

~~~
xeromal
Lots of people do Ramadan while bodybuilding, playing international level
soccer (football) while fasted including no water.

~~~
kolbe
That's not really fasting in a metabolic sense, though. More like time
restricted eating.

------
t0mbstone
Fasting is great and all if you don't have to perform mental tasks throughout
the day.

When I am on vacation and have time off of work to just relax, I regularly
forget to eat, and I barely even notice.

When I'm at work and doing programming, however, even the slightest reduction
in my caloric intake schedule results in me feeling lightheaded and "foggy".
My ability to code effectively plummets, and I also find myself
unintentionally being more irritable towards co-workers.

As such, my job as a professional programmer basically requires me to eat
regularly. Fasting is not an option for me, unfortunately.

~~~
tqkxzugoaupvwqr
You could fast before and after work. Eat all the calories you need in your 9
hour window, fast in the remaining hours.

~~~
t0mbstone
Oh, well, that's basically what I already do. I don't eat at night time
(obviously).

There's a reason why the first meal of the day is called "break fast"...

------
lhuser123
> The metabolic switch usually occurs between 12 and 36 hours after cessation
> of food consumption, depending on the liver glycogen content at the
> beginning of the fast, and on the amount of the individual's energy
> expenditure/exercise during the fast.

I guess that since my breakfast time is around 8 am, then should stop food
intake before 8 pm. The earlier the better. And some light exercise during
that period, even better. Let’s do this!.

------
salimmadjd
About 4 years ago I started changing my diet. I drastically reduced foods with
sugar and carbs and gradually shifted to a one main meal a day regiment. I eat
my main meal (4 eggs, half an avacodo, cucumbers, tomatoes and bell peppers
salad with some feta cheese) around 12-2:00. I usually have an apple later.
Some weeks I fast for 44-48 hours. I workout at a boxing gym twice a week
(about 1.5 hours of a strenuous workout). I’ve been going to the same gym for
10 years, but after changing my diet my stamina increased, sometimes I feel
like I can be there all day.

The 44-48 hour fasting are interesting and are hard. Not because of feeling
hungry(you’re but for me it’s more mental, the thought of all the food I
should eat the next day), but because of other factors. The second night your
brain is very alert, almost feeling like consuming a lot of caffeine or other
stimuli. So if you wake up middle of the night it’s hard to fall asleep again.
In the morning, I’m very hyper again as if I had consumed a lot of caffeine
and if I drink tea or rarely coffee just before the end of my fast the effects
are greatly magnified. Your brain races like mad. I feel like I have an
improved cognitive ability, but I’ve not tested that in any form so it could
just be a reflection of being hyper. That said I’ve gotten physically
stronger, since my diet change and my fasting. I end my boxing workout with
some weights and now I often get comments how strong I am for my body size.
And I know I’ve gotten stronger, because the increased reps and weights I can
do. There was some research on fasting and how your muscles become more
efficient, so I’m not sure if that’s playing a factor or my increased stamina
has allowed me to workout longer and that resulted in increased strength. The
other factor helping me here I think it’s reduced inflammation. It feels like
my muscles recover faster and I have less inflammation problems because of my
diet.

Some interesting anecdotes. One of the guys who works for the gym commented at
my transformation and said I look like a “jock” now and asked details of my
diet. My former boxing instructor who initially told me for best recovery I
needed to eat after a hard workout instead of fasting, now has changed his
diet as well. So there is something to all these and I’m never going back, but
I think we’re still far from knowing the longer term effects of it and also
learning about any genetic variability. But I recommend everyone trying it for
themselves, it’s easy after the first 7-10 days.

------
jiscariot
I've been doing intermittent fasting for about a year--it seems to work for me
because I struggle with controlling portion sizes. Mon/Wed of every week I
limit caloric intake severely--I skip all meals and snack on olives, pickles,
maybe a small amount of avacado in the evening along with a couple of La
Croix. Not sure why olives/pickles, other than I wanted to keep the fasting
foods keto-friendly. Other than that, I used to chew a lot of gum during
fasting, but have since stopped because I'm not sure what exactly "sugar
alcohol" is doing to my body.

It has worked out well for me. I started at 230 in June and hit my baseline of
low 190's in mid-November. I've been there since doing the 2-day fast. It is
not too bad so long as you can stay busy, although it does really affect my
mood on those fast days. It has helped my mountain/road biking immensely.

Just wanted to share my experiences...if anyone has other recommendations for
fasting days, please share.

~~~
abakker
How has it effected your biking? More endurance? Peak Power? or just being
lighter?

~~~
jiscariot
I think it is just being lighter, but the difference in endurance/recovery
from hills, etc is pretty significant.

------
blunte
One thing you have to pay attention to while aiming for a 12+ hour gap is that
you don't accidentally consume calories in drinks, especially from sugar... so
no milk, honey, or sugar in your tea or coffee. A little sugar calories will
prevent the switch flip, leaving you in a starvation state where you feel
awful and eat your own muscles.

~~~
mnort
Folks in the keto/fasting space seem to present salted water as a good option
here

~~~
sameAsYou
Also, bone broth, chicken broth and vegetable broth.

~~~
mikeklaas
How does that work? Doesn't broth generally have calories?

~~~
raarts
No it doesn't and I suspect the broth is just to make the salted water taste
better.

------
rhema
Want to see something crazy? This guy has a huge YouTube following and
preaches (through obscene language) long fast
[https://www.youtube.com/channel/UC_yUeH8TsG5pxqvkOxBtsFA](https://www.youtube.com/channel/UC_yUeH8TsG5pxqvkOxBtsFA).
He experiments on himself and "coaches" people on dieting.

Along with the posh attitudes of fad diets can also come extremism. Do go too
crazy with fasting!

------
DoofusOfDeath
So do we know enough at this point to confidently recommend a fasting schedule
that ought to be safe and worthwhile for most adults?

Or are we still bathing in incomplete/flawed studies, bad reporting, and the
promotion of diet-fads?

This sounds like something I'd like to try if the reported upsides are real,
but I don't have a lot of time to filter out junk science.

~~~
virtuallynathan
It's a pretty easy n=1 trial -- stop eating at 8pm, and eat again at noon.
Maybe exercise in the morning to accelerate the glycogen depletion. Try it for
a month, report back!

There are many studies on this, the literature seems to suggest it works, and
I can say it worked for me.

------
krupan
Anyone read The Hacker's Diet?

[http://www.fourmilab.ch/hackdiet/](http://www.fourmilab.ch/hackdiet/)

I find it interesting that he mentioned as kind of a side note that he only
eats one meal a day. A man ahead of his time :-)

------
mirko22
Robert Lusting has cery intersting book on this, and more specifically the
influence of fructose sugar in diet.

[https://m.youtube.com/watch?v=ceFyF9px20Y](https://m.youtube.com/watch?v=ceFyF9px20Y)

------
projectramo
What if you have to exercise? Should one exercise while fasting?

Or to put it another way, if you only eat between 10am and 6pm (let's say),
what is the best time to exercise? Before work or after work?

~~~
121watts
That depends on the type of exercise you're doing.

~~~
projectramo
x fit?

------
thinkling
The summary mentions that fasting is used to deplete glycogen stored in the
liver.

Doesn't moderate aerobic endurance exercise do the same thing?

If you regularly go on long bike rides, will you get the same benefit?

------
andreygrehov
For anyone interested to read about fasting, there is an amazing book written
by Arnold Ehret, Mucusless Diet Healing System [1], published in 1922.
Interesting fact, the book is from Steve Jobs' reading list.

[1] [https://www.amazon.com/Mucusless-Diet-Healing-System-
Scienti...](https://www.amazon.com/Mucusless-Diet-Healing-System-
Scientific/dp/1884772005)

~~~
tachion
I would be cautious to make health related reading recommendations where the
book comes from 1922 and was on a reading list of a man who was rejecting
science based medication for his serious sickness until it was too late.

~~~
andreygrehov
Good point. The problem is that Steve Jobs ignored Ehret’s concept of a
“transition diet,” and became taken with the idea of being a fruit-only eater
right away.

~~~
stevehawk
I thought the problem was that he ignored getting treated for cancer and died?

~~~
andreygrehov
No way?! How confident are you? Anyways, I mentioned Steve Jobs just as an
interesting fact. Nothing more, nothing less. I don't personally believe that
anybody should be cautious recommending a book. It's a whole separate topic,
but in short, can't help one if he's stupid enough to try whatever is on the
internet, but I'm glad to share useful information with the smarter one.
Otherwise there is no neither progress nor evolution.

~~~
fmihaila
> No way?! How confident are you?

Not just confident, but certain. From Jobs's authorized biography:

 _To the horror of his friends and wife, Jobs decided not to have surgery to
remove the tumor, which was the only accepted medical approach. "I really
didn't want them to open up my body, so I tried to see if a few other things
would work," he told me years later with a hint of regret. Specifically, he
kept to a strict vegan diet, with large quantities of fresh carrot and fruit
juices. To that regimen he added acupuncture, a variety of herbal remedies,
and occasionally a few other treatments he found on the Internet or by
consulting people around the country, including a psychic. For a while he was
under the sway of a doctor who operated a natural healing clinic in southern
California that stressed the use of organic herbs, juice fasts, frequent bowel
cleansings, hydrotherapy, and the expression of all negative feelings.

[...] His friends repeatedly urged him to have surgery and chemotherapy.
"Steve talked to me when he was trying to cure himself by eating horseshit and
horseshit roots, and I told him he was crazy," Grove recalled. Levinson said
that he "pleaded every day" with Jobs and found it "enormously frustrating
that I just couldn't connect with him." The fights almost ruined their
friendship. "That's not how cancer works," Levinson insisted when Jobs
discussed his diet treatments. "You cannot solve this without surgery and
blasting it with toxic chemicals." Even the diet doctor Dean Ornish, a pioneer
in alternative and nutritional methods of treating diseases, took a long walk
with Jobs and insisted that sometimes traditional methods were the right
option. "You really need surgery," Ornish told him.

Jobs's obstinacy lasted for nine months after his October 2003 diagnosis.
[...] In july 2004 a CAT scan showed that the tumor had grown and possibly
spread. It forced him to face reality."_

~~~
andreygrehov
I read the book. It was a sarcastic comment. My point is that the reason why
he died doesn't necessarily have to be linked with the Mucusless Diet Healing
System, especially knowing that he didn't follow all the recommendations from
the said book.

The reason I made my original comment is because the benefits of fasting
described in the submission are known for almost 100 years now (to a certain
extent) and one may find it interesting to know where the roots are coming
from.

~~~
fmihaila
> I read the book. It was a sarcastic comment.

Your sarcasm was misplaced. You stated that "the problem is that Steve Jobs
ignored Ehret’s concept of a “transition diet,” and became taken with the idea
of being a fruit-only eater right away."

That was not the problem at all, as @stevehawk stated and my quote proves. You
are pushing a pseudo-scientific book from 100 years ago and mentioned Jobs's
name to enhance the recommendation's credibility. Jobs's belief in
pseudoscience cost him his life.

> The reason I made my original comment is because the benefits of fasting
> described in the submission are known for almost 100 years now (to a certain
> extent) and one may find it interesting to know where the roots are coming
> from.

And the history of modern chemistry traces back to the days of alchemy; it
doesn't mean there is any deeper truth to be discovered by reading alchemy
books today.

~~~
andreygrehov
I was wrong saying "the problem is", whereas what I should have said instead
is that he didn't even follow the book, so there is no reason to avoid an
interesting read.

> And the history of modern chemistry traces back to the days of alchemy; it
> doesn't mean there is any deeper truth to be discovered by reading alchemy
> books today.

You don't need a deeper truth, but be aware why the believed truth is truth,
ie seeing the problem from all the angles. You don't know what you don't know.

------
kvhdude
as always there is news to the contrary indicating harmful effects :
[https://www.medicalnewstoday.com/articles/321864.php](https://www.medicalnewstoday.com/articles/321864.php)

------
mythrwy
I'm not at all overweight and personally don't see what this fasting thing is
about.

If I even skip breakfast forget hard thinking or strenuous effort.

------
mnort
seems to be becoming more and more “scientifically” clear that brains run
better on ketones, and burning fat is cleaner for the body

~~~
srik
Wait I might have to dig up the sources. But it is generally accepted in the
“Keto sphere” that the brain runs on glucose. Even in ketosis the body creates
some glucose for this purpose.

~~~
virtuallynathan
I don't have sources handy, but IIRC the brain will generally to run on about
a 60/40 or 70/30 mix of ketones/glucose, but in some experiment they gave
people in ketosis a does of insulin to drop their blood sugar to near 0, and
they didn't pass out and were otherwise fine.

------
aviv
Lol. For years I talk about fasting here on HN and get downvoted to oblivion.
Intermittent fasting is what they now say is healthy because it means you're
still consuming food so they still make money. A far better alternative and a
cure to many many "diseases" (yes, cure, I said it) is a prolonged water fast
(10 to 40 days), and/or a dry fast (no food no water) for 2 to 10 days.

