In 2003, the famous stunt artist David Blaine spent
44 days without food suspended in a transparent box above London.
“I also didn’t go to the bathroom for a month and a half.”
“What?”
Though Blaine’s stunt pales in comparison to the Scottish Man Angus Barbieri who entered
the Guiness Book of World Records in 1971 for surviving a year long fast.
So, what happened to Blaine and Angus? In this video, we’ll take a look at what
happens to the brain, organs and muscles and hormones when you go without food
for longer and longer … 12 hours to 2 days to a week or even several months.
“And as the weeks draw on, doctors say he’s shown the first signs of starvation.”
Fasting is very popular recently because of the huge health and
cognitive benefits to be had from even one or two days of fasting.
After a day of fasting, you start getting very high pulses in growth hormone levels throughout
the day. Your hunger hormone ghrelin also go down. Over 48 hours of fasting, the protein
called Brain Derived Neurotrophic Factor which literally makes the brain grow increases 3.5 fold.
Over a 72 hour fast, the fat storage hormone insulin drops quite a bit.
But, fasting hype isn’t new at all. More than 100 years ago in 1911, Upton Sinclair
published a popular book called the Fasting Cure where he reports on multiple miraculous health
improvements from various people’s multiple day fasts, with some fasting longer than a month.
By 1972, the Soviets had developed what the LA times called a cure for just about anything:
eating nothing for 30 days. Some research
has found fasting to significantly boost mood and be effective for anxiety and depression.
So while David Blaine was sitting in that glass box with nothing to do,
his body was doing a lot. After about 8 hours without food, his body
would shift to mostly rely on the stored sugar or glucose stored in his liver for
energy… and David would start to be getting pretty hungry.(BMC) But he only has so much
glucose stored in the liver to maintain his blood sugar, so what happens when he runs out?
Well I can actually find out that out for myself by stabbing this thing
into my arm and then I’ll eat nothing for 2 and a half days.
This thing on my tricep is called a continuous glucose monitor because it continuously monitors
my glucose - my blood sugar. I've been fasting for about 63 hours now so let's take a look
at my blood sugar. So as you can see… my blood sugar while I was sleeping was relatively flat.
But then when I woke up, it went up a little bit, even though I haven’t eaten anything.
If we look at my blood sugar for the whole 64 hours I fasted, you can see it fluctuated
a lot … here it spiked up when I went to the gym. But… it only takes about 28
hours to use up all the glucose stored in my liver … so, where’s the glucose coming from?
One reason my blood sugar didn’t go down and down to zero is because the body can make
the small amount of glucose it needs.
But wait a minute, this couldn’t be good for the brain because it needs tons of energy…
At the same I was depleting my glucose stores, my body started to generate an alternative fuel
source - ketones. Ketones are such a great source of energy for the body that when you’re fasting,
2/3rds of the brain’s energy needs are met by entirely ketones,
the other 1/3rd comes from the glucose your body makes.
Ketones in fact are considered to be the most energy efficient fuel for our bodies , providing
more energy per unit oxygen used. Considering the brain is the most energy intensive organ,
demanding 20% of the body’s energy budget, more energy bang for your buck is great news.
The interesting thing about these ketones is that they’re not just a replacement fuel
but they're really beneficial to the brain. As mentioned before, after 48 hours of fasting,
levels of the protein BDNF increase 3.5 fold. BDNF is a potent stimulator of growth in the brain.
Dr John Ratey explains in his book Spark that when researchers sprinkled BDNF onto brain cells
in a petri dish, the cells automatically started to grow and sprout new branches.
This kind of structural growth is necessary for learning and essentially improves brain function.
“BDNF, which I call Miracle Gro for the brain.” In fact,
BDNF is associated with cognitive improvement and improvements in depression and anxiety.
And, this paper explains that a stimulator ofBDNF release is ketone bodies.
Here’s a paper that looked at 1422 people who fasted for 4 to 21 days. What’s interesting
is I think most people would be concerned about their mental or emotional state while
fasting - suspecting a long fast would make them progressively more hungry and irritated,
unfocused or drained of energy. However, for over a 1000 people,
emotional well being significantly increased over 5, 10, 15 and even 20 days of fasting.
So by day 5 in David Blaine’s fast, he may have been feeling actually
pretty good. Several people, myself included, have reported that sometime
after day 4 and as early as day 3 of a fast, they feel especially focused and present with
a lot of energy. This paper from before reports that sometime between days 2 and 7 of a fast,
there is an improvement in depressive symptoms - people experience an improvement in mood,
alertness and even a sense of tranquility. This may be due to very high ketone levels. Normally in
people not eating a ketogenic diet, ketones are quite low, most likely around 0.1 mmols but no
higher than 0.5mmol. Mine after a weekend of very un-ketogenic eating are 0.1mmol. But as you fast,
ketones will steadily rise - by day 5 of a fast, ketones peak, reaching as high as 7-10mmol
Also by day 5, we should expect that David Blaine wouldn’t have been hungry anymore,
maybe starting even earlier than that.
Going back to Upton Sinclair’s book “The Fasting Cure,” he explains that it is part of the natural
course of longer fasts for hunger to disappear by day 3 or so. I’ve found this to be the case for
me as well. He also says depending on the person it can take days or weeks for hunger to return.
In fact, the study looking at 1422 people fasting 4 to 21 days,
found that hunger disappeared for 93% of the people.
This thing is a ketone ester, one of the worst things I’ve tasted - basically drinkable ketones.
Two things I’ve noticed from it: if I take enough, it increases my focus and mood, a little bit like
I had a cup of coffee. The other thing is it takes my hunger away for a little while.
Ketones are an appetite suppressant. This paper found you can lower people’s feelings
of hunger by having them drink ketones in the form of a ketone ester, just like I did.
Let’s take a quick look at longer fasts… Going
back again to the study on over 1000 people fasting from 4 to 21 days,
for 84% of the people who had health issues, those issues improved from the fasting.
One study found that a patient essentially cured her diabetes
with only two weeks of fasting. Another severely obese woman cured her diabetes with
four weeks of fasting. Now, that woman regained all the weight she
lost, but interestingly her diabetes stayed in remission for over year after that,
suggesting fasting could have had some beneficial effects unrelated to the massive weight loss.
Going back to the 1972 LA times article - a man in
it named Vladimir reported to have cured his arthritis with 45 days of fasting.
But what happened to the Healthy David Blaine?
For David Blaine, it wasn’t all miracles and ketogenic euphoria. He experienced heart
palpitations, blurred vision and backaches. Blaine lost a ton of weight during his fast:
24.5 kilos or 54 lbs, but according to the report published about Blaine in the journal Nutrition,
42.4% of that was muscle and only 26.1% of that weight loss was fat.
If you’re gonna fast as long as 44 days, you’re going to lose some muscle, however if you wanted
to lose as much muscle as possible, you’d probably want to fast in the same way David Blaine did.
Not being able to move around has serious consequences for muscle.
A 2016 study found that when healthy people were eating a proper diet with ample protein,
simply subjecting them to strict bed-rest for a week had them lose a ton of muscle mass.
On the other hand, a 2017 study had men stop working out for 2 weeks…
and simply allowing them to walk around prevented them from losing any muscle.
Tim Ferris wrote in his book “Tools of Titans” that during his first clinically supervised
7 day fast they didn’t let him exercise and he lost 12 pounds of muscle. However,
when following a fasting protocol designed to get him into ketosis as soon as possible - involving
brisk walking for four hours, he claims to have lost zero muscle mass on a ten day fast.
As mentioned before, fasting raises growth hormone… growth hormone decreases body fat,
it increases bone density and it helps you build up muscle
and ketones also protect your muscle from being broken down.
A 1989 study found that simply injecting ketone bodies into people not only prevented proteins
from being broken down but the ketones increased protein synthesis - both great things for muscle
Not every aspect of fasting is good for muscle, though. IGF-1 a key factor in muscle growth goes
down and remains quite low over a 10 day fast. But if you’re doing a fast, eating low carb
before the fast and getting plenty of low intensity exercise throughout the fast
should help you get into ketosis quickly and prevent you from losing much muscle.
All this said, you can’t just fast excessively long without consequences.
According to a 1969 case report, a 20 year old woman weighing 118kg or 260 pounds
did a 210 day fast, in the process she lost 60kg or 132 pounds. And she did
survive a week of refeeding … but she went on to die of a heart attack after
that. The autopsy found that this extreme fast had significantly atrophied her heart.
This paper says that based on observations made on fasting animals,
once you get into ketosis, prolonged fasting isn’t all that eventful - you basically along
burning your body fat for energy. However, at least in animals, when fat stores reach 10%
of body weight the body enters a dangerous stage where protein
breakdown increases massively - and the muscles and heart can waste away.
…a couple sources say that you’re really increasing your risk for
negative consequences once you get above 40 consecutive days of fasting.
Before 1973 there had been recorded at least 4 other fasts longer than 210 days that did
not end in heart attack like that 20 year old woman. Perhaps these people had so much
body fat that even after 210 days, they didn’t reach that drastic muscle tissue wasting phase.
In fact, Angus Barbieri’s 382 day fast was relatively uneventful with the authors of
his case report simply writing that “prolonged fasting in this patient had no ill-effects.”
Angus broke his fast with a boiled egg and a slice of bread, and told reporters "[I] thoroughly
enjoyed my egg and I feel very full".(S) During the fast, Angus steadily lost weight at an average
rate of about three quarters of a pound or one third of a kilogram per day, losing a total of
276 pounds or 125 kilograms. And, what was huge was that he kept the weight off. His fast took
him from 456 lbs down to 180 lbs and 5 years after the fast he still weighed only 196lbs.
This is really interesting because on the other hand, many of the participants in the Biggest
Loser TV competition who frequently lose over 100 lbs … end up gaining back most or all that weight.
“If you want 5 minutes of fame and drastic weight loss that you’ll never keep off,
then join the Biggest loser.”
“Scientists followed contestants from the TV show the biggest loser
and they found that when the cameras went off, the weight often came back on.”
“And within about 4 or 5 years I’d put back on all the weight.”
A study done on their physiology found that the intense exercise
and caloric restriction that had them lose plenty of weight
left them with an abnormally a ravenous appetite. (Clip 250,000 prize)
“Germanakos faced big challenges after returning home - telling Today
I’m a morbidly obese person in a fit body. I’m hungry all the time.”
Now there’s a phenomenon where when in certain people who lose weight, their hunger hormone
ghrelin goes up, suggesting they become more hungry. But when you fast, ghrelin goes down. And,
it seems to be that ketone bodies are what prevent ghrelin from going up when you lose weight.
In fact, this 1968 paper claimed that after 2 weeks of fasting, obese people were able
to be completely satisfied with a diet of a mere 800 calories for another 2 weeks.
It’s probably not reasonable to expect to consistently have that much of a reduction
in hunger, but this hunger lowering effect may be thanks to reduced insulin. Dr. Robert Lustig says
that insulin blocks your brain from picking up on the leptin signal. Leptin is a hormone that
essentially makes you feel full. “And that’s what’s driving obesity. Insulin blocks leptin
at the brain and makes you hungry. The higher your insulin goes, the hungrier you get.”
Dr. Lustig says that often in obesity, people have very high leptin levels but
that leptin signal is blocked by very high insulin levels. When you fast,
insulin drops a lot… so we should expect people to get full more easily after a fast.
The beauty of fasting is it’s so simple … if you’re not sure how to do it,
you can grab one of these instructional T-Shirts in the description. … if
you’ve never fasted before or are taking medications, take it slow
and see what a professional has to say before you fast for many days at a time.
I think for a while, not eating anything has seemed kinda scary.
“She hasn’t eaten anything in 3 days! Is that true?
You haven’t eaten anything in 3 days?” In this Full House episode DJ is cautioned
that not eating for 3 days will have serious side effects on her health.
“DJ, if you’re starving yourself, you could do serious damage to your body.”
This might not be the best example because DJ is quite young, seems like she doesn’t know anything
about fasting, and wasn’t approaching fasting with the healthiest mentality
but if she has enough extra weight that losing weight would not harm her health, why is fasting
for 3 days at a time in a healthy person assumed to be such a dangerous way to lose weight?
One thing I didn’t mention is that you can feel bad or fatigued while fasting simply due to a
lack of electrolytes. When you fast, insulin goes down and the kidneys have you pee out
a lot of electrolytes. Replacing them can make you feel way better. That’s where this video’s
sponsor LMNT comes in. As someone who fasts and is often on a ketogenic diet, I was already a
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