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I love life,
so I want to remain young, energetic, enjoy it for as long as I can.
I'm medically trained.
I know all the standard advice for staying healthy.
But in my case, it doesn't seem to be working.
I've discovered that my body is not the lean, long-lived machine
I would like it to be.
-A third of your body is fat.
-Thank you...for making that point so emphatically.
I wanted to see if science can offer a different way to stop the rot,
slow the clock,
so I set off to find experts
who are trying to combat the ravages of ageing.
-We are rewriting human physiology here.
If you can find something else that you can do that it doesn't hurt you, that benefits you
and that causes these changes, I'd like to know.
What I discovered was truly surprising.
It involves no pills, no injections and no hidden cost.
It's all a question of what you eat.
Or rather, what you don't eat.
Last night, I dreamt I ate a sandwich and then I felt fantastically guilty.
It's about fasting.
But fasting made easier.
If I were to go onto Joe's lifestyle...?
In a year, you are going to be cured.
The big thing is that this is the beginning of something which I think could be huge.
If it takes off and if it heads off in the direction I imagine it will,
then this...this could be genuinely revolutionary.
There are plenty of people who stay young and fit
well beyond retirement age.
They mainly do it the traditional way -
through lots and lots of exercise.
Today, I've come to the London Marathon.
Nearly 36,000 bodies of all shapes and sizes
are tackling the 26-mile course.
Some are young,
many not so young.
There's an absolutely fantastic atmosphere here.
Now, I have never run the marathon
and I have no plans to ever run the marathon,
but there are plenty of people running today
who are far older than me.
There are 7,000 people in their 50s
and, incredibly enough,
there are seven people who are in their 80s or older.
I'm going to trying and flag a few of them down
to ask how they do it.
Hello! How are you? Hello!
-How old are you?
-And how old are you?
-What's the secret, then, running?
-Just eating well.
-Hard work son, that's all!
Anyone who can run a marathon in their 70s deserves my respect,
but I'm waiting for a man who makes septuagenarians look youthful.
Fauja Singh is amazing.
He has been active all his life,
but he only took up serious running in his 80s.
So what is it that keeps him so remarkably fit and energetic?
Hi, there. Nice to see you.
-How old is Fauja?
Born on 1st April 1911.
Unfortunately he hasn't quite mastered the English language yet.
Do you mind asking him how he's feeling?
THEY SPEAK IN PUNJABI
-He goes, "It's not easy..."
But the job's got to be done, cos he's not finished yet. You're not going to give up, are you?
Although he's 101,
Fauja has never had surgery,
he shows no signs of heart disease...
and he takes no medication.
He believes that his long life
and his incredible health is down to his diet.
So, any particular diet?
He has no particular diet.
It's a simple Punjabi farmer's diet, so just fresh food,
-but his secret is that he has smaller portions.
In poor countries, people die of starvation.
In rich countries, people die of over-eating.
So, how much does he eat, compared to you or I?
He would eat what would be considered half a portion,
almost a child's portion.
So a child portion is probably about half the amount of calories you or I would eat?
By restricting his food intake so dramatically,
Fauja has unknowingly been testing a theory that has been around
nearly as long as he has.
A scientific theory which is only now really coming into its own.
I've taken the Tube to the finish line.
I want to catch Fauja become, hopefully,
the world's oldest marathon runner.
And after seven hours and 49 minutes, he succeeds.
CHEERING AND APPLAUSE
Can I congratulate you?
That is absolutely unbelievable - he's 101 years old
and he has just covered 26 miles.
Now, I can't imagine that, in 50 years' time,
I'm going to be running down The Mall,
but I want to be like him.
I want to be mentally active and physically active, I want to stay younger for longer.
For decades, teams of scientists around the world
have been intensely studying ageing.
Now, clearly, genes play a significant part in how quickly and well we age,
but there's nothing much you can do about your genes.
There is, however, something you can do about what you eat.
And here in America, they are starting to turn out some truly remarkable research
linking food with longevity.
It seems it's not just about WHAT we eat, but how and when we eat it.
Our story begins in the dust bowls of America during the 1930s.
There was a terrible drought, food was scarce,
and the whole country was in the grips of the Great Depression.
Now, you would imagine, in such difficult times,
that life expectancy would fall, but in fact it rose.
During the darkest years of Great Depression - 1929 to 1933 -
life expectancy increased by a remarkable six years.
Now, on the face of it, that is really surprising,
and yet, clues as to why could also be found from research done back in the 1930s.
Nutritionists at Cornell University working with animals
discovered that if you severely restrict
the amount they eat, they live longer.
Much, much longer.
So the next obvious question - if you do the same with humans,
will it have the same effects?
Well, it's been eight decades since that observation,
and only now are scientists really beginning to understand
the link between calorie restriction and longevity in humans.
At long last, it seems, we are starting to get answers.
Washington University is at the heart of this new science.
We are rewriting human physiology here!
It's astonishing, you know,
how simple dietary intervention can really change
how the human body works, basically.
'Professor Luigi Fontana has spent the last ten years studying a group of people
'who severely calorie restrict every single day.
'And he is astonished by what he's found.'
These people, they look like a different species.
-That's quite a big statement, isn't it?
We are finding that they are going to live longer than their parents and brothers
on the typical American diet, or Western diets.
'Luigi is clearly impressed,
'so I wanted to meet one of this new species of human for myself.'
-A lovely, lovely house.
-Were the directions good?
-Very good, thank you.
Joe Cordell is a CRonie -
a calorie restrictor on optimal nutrition.
And that means a lot of fruit and veg.
I went ahead and kind of put everything out
-because I thought you might want to have some breakfast.
-That would be delicious, thank you.
When I imagine a calorie restrictor,
I imagine someone who lives basically on a couple of carrots, or something like that.
I didn't think you'd go in for breakfast.
'Joe kicks off his day with a mountain of fruit,
'some of which he then throws away.'
Then what I like to do is add some apple to it, but when you're in my position,
I want to get as much nutritional value as I can for the calorie,
and virtually all the nutritional value is in the peel.
So you're going to slip the peel in and throw away the rest of it?
You're going to do the reverse of what most people do.
It's great, because literally 95% of the nutritional value here...
-Is in the skin?
-Yeah. The rest is sugar and calories.
-This is generally what I'll have each morning
-The whole thing?
-That's a big bowl.
Do you ever think, "What if I'm wrong? What if it's all wrong?
"I've done this for 10, 20 years, and then a new bit of science comes out
"which says it's actually all nonsense."
I tell you, my brother, who weighs 100 lb more than I do,
he's about my age. He's all the time making the joke to me
that he's going to end up out-living me
and, in his opinion, I will have suffered for nothing.
But the point is, I enjoy doing it.
Living a healthy lifestyle is fun.
'There are an estimated 100,000 CRonies worldwide -
'people living on a diet which is rich in nutrients
'but low in calories.
'Joe looks fit, but not impressively young.
'Perhaps Luigi has been exaggerating.'
What I'd love to do is take you off and do a number of tests
and see just how we compare.
OK, I'm game. So, is this a challenge?
This is a challenge indeed, a challenge I suspect I may well lose!
For a decade, Joe's been eating 1,900 calories a day.
I've averaged around 2,300,
quite a few of them donuts and burgers.
How much do you think you weigh?
Probably about 180. Ooh, more than 180!
I should be around 134, 135, 136.
We just have to move it down one notch.
-Oh, right on.
We're both in our 50s, and I really don't think
we look like different generations, let alone species.
So how different are we?
I just need for you to relax. Sit still, no talking.
Some of the simplest ways of assessing ageing don't need specialist equipment.
Oh, this is good.
Balance is controlled by your inner ear.
'As you age, ear structures deteriorate
'and your balance gets worse.
-'You can test it by standing on your weaker leg
'with your eyes closed.'
-How long did I make?
-Not very good.
'Not good at all.
'The average 55-year-old should manage 8 seconds.'
You're down to...
Yeah, you're doing well for the average 20-year-old.
Over 30 seconds is what most 20-year-olds can manage,
but it's one of those skills that drops off dramatically.
-I think you've proved a point.
-You can stop, yes.
'Another good test is reaction time, which drops off with age.'
Not good. Eight.
'This one only needs a ruler.
'At our age, you should be able to catch it around the five-inch mark.'
Very good. That was 4. You're doing pretty well, I must admit.
Luigi's methods are rather more scientific.
We did a range of other medical tests,
including blood tests.
Now he's about to give us our results.
Feels like being in the headmaster's office, doesn't it?
Waiting for the results.
Will you get an A-star? Will I get a B-minus?
'Luigi's face tells me
'that what I'm about to hear is not good news.'
Total body fat in Joseph is 11.5%.
This is typical of a super athlete.
11% body fat is very low
for a 54-, 55-year-old man.
Yours is 27.1% fat.
A third of your body is fat.
Thank you...for making that point so emphatically!
'And he's still not done talking about my fat.'
Abdominal fat is around 30%.
Abdominal fat is really the bad guy.
The higher the abdominal fat, the higher the risk
of developing type 2 diabetes, cardiovascular disease.
No doubt about it. It's also a risk factor for cancer.
So, basically, your cardiometabolic profile,
it's not good. For your age.
I think you should do something to improve it.
What we can say is that Joseph
is not going to develop cardiovascular disease.
It's impossible to develop stroke,
myocardial infarction or heart failure.
These three diseases are responsible
for 40% of the deaths now in US and UK.
-No chance he'll die of that?
-I mean, one in a million.
And if I were to go onto Joe's lifestyle...?
In a year, you are going to be cured.
I now understand what Luigi means.
It is as if we are two different species.
Joe's diet seems to be keeping his organs in pristine condition.
My diet is undermining my health, and fast.
Well, that was very sobering. Luigi does not mince his words.
He talked a bit about abdominal fat.
In fact, he talked quite a lot about my abdominal fat.
I've never thought of myself as particularly fat.
But it was the sort of two visions he held out to me.
One, where, if I continue as I am at the moment,
I'm heading almost certainly for heart disease and possibly worse.
The other is, if I embrace the calorie restriction way,
he said I could be effectively cured in less than a year.
My risk factors would move from being almost certainly
a cardiac victim at some point
to one in a million.
When you put it as starkly as that, it's given me a lot to think about.
Even though the evidence supporting the benefits of calorie restriction
is getting stronger all the time,
I cannot in all honesty imagine myself doing what Joe does.
Which creates something of a dilemma.
So, what I really want to do is try
to understand the ways in which calorie restriction works,
then hopefully I can get all the delicious benefits
without actually having to do it.
I'm in Los Angeles,
a city that is notoriously addicted to youth.
In fact, many people here seem to think
that growing old and wrinkled is optional.
I'm not going to see anyone as superficial as a plastic surgeon.
I'm here to meet one of the world's foremost experts on ageing.
Professor Valter Longo studies the complex mechanisms which control ageing.
He's honed in on a critical pathway that links what we eat with how we age.
He's taking me to see two mice.
They are both the same age, same species, same sex.
But there's one significant difference between them.
The little one is going to be living an awful lot longer
than the big one.
This little mouse right here
holds the world record for longevity extension in a mammal.
Oh, right. That is remarkable.
So, how long would these subspecies of mice last?
The big mouse here, about two years,
and the little mouse, about a 40% longer lifespan.
Right. They're very different, aren't they?
Whoa! He is trying to bite me.
-I could feel that one going through.
-Should've had the double glove.
I learned the hard way!
The big mouse already has a 50% chance of being dead.
OK, so he's doing well to be alive?
He's lucky to be alive, that's right.
-The small one probably has another year to go.
The little guy will live on to the equivalent of what, 120 in human?
Exactly, yeah. Another 30 to 40 years in human years.
-Can I pick it up?
-Go ahead. By the tail.
The little mouse I'm holding
is actually a man-made creation.
The reason he's so small and so long lived
is because he's been genetically engineered.
He has incredibly low levels of a growth hormone
called Insulin-like Growth Factor 1.
And it seems IGF-1 is a key factor
linking calorie restriction and longevity.
Clues to the link come from this group of people
who live in a remote region of Ecuador.
They have a very rare condition called Laron syndrome,
which affects less than 350 people worldwide.
That's you, is it? It makes you look like a giant, doesn't it?
I'm the tall guy there.
The shortest one is just over three-and-a-half feet tall.
-Up to my belly button. Is that right?
'What interests researchers like Valter is not their size,
'but the fact that they seem to be virtually immune to two of the West's biggest killers.'
The big findings, of course,
were, they don't seem to get either diabetes or cancer.
Do they do all the normal, sensible things we all do,
-like drink, smoke and all that?
-Yes, they do the normal, and more,
so they a very unhealthy lifestyle.
Most of them are to some extent at least overweight.
They seem to really not watch anything they do.
They smoke or eat very high calorie diets,
and then they look at me and they say,
"Oh, it doesn't matter. I'm immune."
But the incredible thing is that there's no evidence
of a single one of them ever dying of cancer,
yet their normal-height relatives get cancer like everybody else.
People with Laron syndrome have a mutation which makes them small,
but which also seems to protect them against all these diseases.
It's incredible working with them.
It's a great group, and of course for us is a group that in one mutation,
can tell us about diabetes, cancer, cardiovascular diseases and ageing.
The Ecuadorian villagers and the long-lived mice
have something in common.
Their bodies produce exceptionally low levels
of the growth hormone IGF-1.
This discovery helped Valter piece together role that IGF-1 plays
in the complicated business of ageing.
Our bodies are normally in go-go mode -
cells constantly driven to divide by IGF-1.
But when IGF-1 levels drop,
our cells shift into a completely different mode.
The body slows production of new cells
and starts repairing existing ones instead.
DNA damage is more likely to get fixed.
And that's why the mice AND the villagers are protected
from age-related diseases.
But what's the link to calorie restriction in humans?
Valter has lined up a very simple, very Californian analogy.
It turns out there is something in the food we eat
that affects how much IGF-1 our bodies produce.
That something is protein.
When we eat a lot of protein, our cells get locked in go-go mode.
So it's basically like slamming your foot on the accelerator,
-saying, "Go! Go! Go!" Is that right?
It's pushing the cell to burn fuel.
In go-go mode,
the body is more susceptible to some cancers and diabetes,
because your cells are growing too fast
for damage to be efficiently repaired.
So it's like driving your car all the time
and never taking it to the mechanic.
Right, so that's the key, basically, is to somehow find a way
to switch your body from going, "Broom, broom, broom,"
-into a sort of repair mode, "Look after me, make my DNA better."
So, how do you reduce your IGF-1?
Well, studies on calorie restrictors suggests that eating less helps,
but it's not enough.
As well as cutting calories, you have to cut your protein intake.
Not entirely - that would be a very bad idea.
It's about sticking to recommended guidelines,
something most of us fail to do.
And you don't have to be a CRonie to lower IGF-1.
There is another way - fasting.
In fasting, there is a much more dramatic and much quicker response,
and so, within 24 hours, you decrease your glucose level
and you decrease your main growth factor, which is IGF-1.
I do find it hard to believe that just a few days of fasting
is going to be enough to jolt my body into a more healthy state.
But I'm certainly intrigued, and I want to find out more.
So I've had my IGF measured back in London,
and they tell me that it's 28.
Is that good? Bad?
That's not very bad, but that's high enough
that, based on a number of studies, including our own,
it puts you in a higher risk category for several different cancers,
including prostate cancer.
Valter believes I should start to see some pretty impressive results
after just three days and four nights of fasting.
But it's a daunting prospect.
I think fasting's quite tough, isn't it? Have you done it yourself?
I've done it myself, yes,
I've fasted for four days several times
and to me it was very tough, yeah.
And still, if I look ahead at doing fasting,
I see it as a tough four days, I'm not looking forward.
Some people do, but I don't.
I'm Italian, so I look forward to eating well, you know.
-I'll bear that image in mind.
The greedy Italian stopping eating when I'm feeling weak about it.
-There you go.
Prolonged fasting can be dangerous
and Valter thinks it should only be undertaken by people in good health
and preferably, under close supervision.
So he will be keeping an eye on me.
OK, I've decided I'm going to try this fast,
which is going to be a three-and-a-half-day fast
and all I'm going to have is lots of water, black tea
and one 50-calorie Cup-a-Soup a day.
Now... Oh, God, I have never done anything quite like this before,
so I imagine it's going to be really tough.
But I'm interested.
I'm also, I must admit, quite concerned about some of
the rather bad news, health news I've been getting recently,
so, um...it'll be a challenge, but I'm sure I'll manage it.
And so, my fast begins.
Right. It is now 10.30 at night and I am hungry.
It has been, oh, just about 25 hours since I last ate a meal
and the prospect of going to bed while hungry is not a great one.
I think it's getting to me, because last night I had a dream
and I dreamt I ate a sandwich and then I felt fantastically guilty.
So vivid, I had a look round to see if there were any crumbs in the bed, but there weren't.
I guess time to go to work.
Simple dietary intervention
can really change how the human body works.
It puts you in a higher risk category.
Just as Valter warned me, the first day was tough.
Not really because I was that hungry,
but simply because I had never done anything like this before.
It was fear of the unknown.
My nightfall, I'm beginning to think this is a very bad idea...
..particularly when I had dinner with the crew.
Or rather, when they had dinner.
So, yeah, here I am in a nice old Korean restaurant
with the rest of the crew.
And they are currently digging in...
Enjoying it, guys?
It's a good smell. I really, really wouldn't mind a little bite.
I do feel very hungry.
Fortunately, my dinner is waiting for me in my hotel room.
I had to leave, I couldn't bear it any longer.
-My delicious miso soup here.
Give a bit of a stir with the hotel pen,
because there's no other cutlery around.
Health. 25 calories' worth.
And I'm looking forward to it.
OK, final full day of fasting.
Delicious breakfast here, black tea.
I'm feeling a bit light-headed but otherwise actually all right.
So, just 24 hours to go
and now I'm pretty confident I'll be able to do it.
I've learnt that hunger does not build and build,
but comes in waves that pass.
By now, I have depleted my body's store of glucose
and will have switched to burning fat for fuel instead.
And if Valter is right,
my liver should also have stopped producing so much IGF-1,
putting my cells into repair mode.
Finally, it's 7am, day four, I'm getting my blood test done.
-So, after this, I can go and have breakfast?
The first food for three-and-a-half days,
the first food for 86 hours. Well, who's counting(?)
I'm just hoping that this is going to show some change,
particularly in my IGF, cos if I have spent the last three-and-a-half
to four days not eating and the results have been absolutely zero,
that would be very, very depressing.
The fast is over.
Mmm. Ah! That is very...
I can just sort of begin to feel the empty spaces.
I wasn't actually terrible hungry when I woke up this morning, but...
..when I start eating this, I realise what it is I was missing.
Later that afternoon, I meet up with Valter to find out
if it's all been worthwhile.
I broke my fast this morning, I had some porridge and some bacon
-and I feel better.
-Oh, good, good.
I'll feel even more terrific if these results are any good.
Yeah, let's take a look at them.
So, your insulin-like growth factor one, IGF-1, this is the normal value.
-The bad news, you're almost at the top of the normal range.
For American standards, you're doing good.
But not good full-stop, but not bad. I'm an average American, am I?
That's right, yeah. And the good news is,
-with your fasting diet, you dropped to almost half.
-That's big, isn't it?
-That's a big drop.
It's a very dramatic drop, so you respond very well.
I have to say, it was fascinating.
Seeing that is very, very... um, surprising.
'Surprising - and a huge relief.
'Halving my IGF-1 should cut my risk of certain cancers,
'like prostate cancer, which my father had.
'My blood sugar has also dropped to healthy levels,
'which I'm really pleased about.'
I challenge you in four days to get more extreme metabolic changes
than these with anything you want.
I think this is quite extreme enough! Yeah.
Yeah, but, you know, if you can find something else that you can do,
that it doesn't hurt you, that benefits you
-and that causes these changes, I'd like to know.
But Valter says, unless I switch
to a lower protein, more plant-based diet,
the effects won't last.
I'll also need to fast once every couple of months,
to maintain the benefits.
Can I really see myself doing that?
You have to make a decision now, in your case,
what do you want to do, you know?
And there is a lot of drugs that you could be taking,
and is that what you want to do?
And if you do so, in a few years, or in a number of years,
you're going to be the typical 65-year-old in Europe
that takes eight drugs a day, and so that's the option.
MICHAEL LAUGHS And that's your call.
Thank you, OK! That's quite an interesting choice!
That is really, really impressive,
that in just three-and-a-half days,
if this data is right, and the animal data is right,
I have massively decreased my risk
of a whole range of age-related diseases.
The big question in my mind at the moment is,
can I do fasting once a month,
for however long it takes?
Or is there a better way, a different way,
a more manageable way out there,
that can do much of what this does,
but perhaps with a little less pain?
What I've discovered about myself is that
the biggest problem with prolonged fasting is me.
VALTER: 'You have to make a decision now.
'Fasting is tough.'
Despite knowing all the wonderful benefits...
..I just can't bring myself to do it.
But the great thing about science
is there is always someone doing further work,
building on what others have achieved,
which is why I'm here in Chicago.
Here, they are doing studies not just on mice, but also on humans.
And they seem to have found a way
of making fasting a lot more palatable.
I'm here to meet Dr Krista Varady,
who has been researching something that sounds easier.
Alternate day fasting.
-Hello! Hello there!
-Very nice to meet you.
-Nice to meet you! My name's Krista Varady.
Hello! So what have you got here, then?
So this is some of the components that we'd use
in an alternate day fasting diet.
It basically involves a day of pretty heavy calorie restriction.
For women, about 400 to 500 calories a day,
and for men, about 500 to 600 calories a day,
and that's actually just as one meal, around lunchtime.
We call that the fast day.
So the fast day isn't about total abstinence.
It's about meals that look like this.
What's great about alternate day fasting
is what happens on the alternate days.
And then that's alternated with something we call the feed day,
which is where you can eat whatever you want. Absolutely whatever you want.
So here's the pattern of alternate day fasting.
It certainly sounds easier than either prolonged fasting
or the daily calorie restriction I looked at earlier.
But is it as effective?
Well, Krista's currently doing a trial with overweight subjects
which suggests it might be.
What we saw was that the alternate day fasting group
actually lost a bit more weight,
so about 5lb more after the 6-month period.
And they actually saw some pretty nice decreases in LDL cholesterol,
as well as triglycerides.
So LDL cholesterol is the bad cholesterol,
and triglycerides - basically higher amounts of that
can lead to heart disease and age-related disease.
We also see really nice decreases in blood pressure
over the course of the trials.
So, again, another key heart disease risk factor.
'In addition to so far rather limited human trials,
'there's lots of good evidence from animal studies
'that alternate day fasting, ADF, is safe and effective.
'I'm convinced enough to try it.
'Yesterday I fasted.
'Today I feed.'
So hopefully, we will make it back...easily enough.
-Ooh, magical mystery tour! I like that!
MUSIC: 'Johnny B Goode' by Chuck Berry
-Hi, thanks for stopping.
May I take your order, please?
# Deep down in Louisiana Close to New Orleans
# Way back up in the woods among the evergreens
# There stood a log cabin made of earth and wood
# Where lived a country boy named Johnny B Goode. #
A very good choice!
I particularly like the green stuff that's oozing out of it.
So, I must admit,
I am surprised to be here.
I kind of imagined you'd be sticking on a sort of, um,
you know, a veggie diet or something like that.
Or, yeah, a lot of salads or something on the feed day?
No, actually as long as you stick to the calorie goals on the fast day,
you can literally eat whatever you like on the feed day.
'One of Krista's most recent studies compared two groups on ADF,
'one eating high fat, the other low fat,
'on their feed days.'
I'm concerned about my blood glucose,
I'm concerned about my cholesterol,
-I'm concerned about a load of stuff.
Are those not, sort of, made worse by eating high fat?
That's actually what we thought would happen.
And then, surprisingly,
we saw the same decreases in LDL cholesterol,
so that's the bad cholesterol,
and in triglycerides,
and also in blood pressure.
So in terms of cardiovascular disease risk,
it didn't matter if you were eating a high-fat or low-fat diet.
Another big surprise was that, after a day of fasting,
people rarely gorge themselves on their feed days.
So when we ask someone to consume 25% of their energy needs on the fast day,
I just thought that when I started running these trials,
that people would eat 175% the next day.
But right from the get-go, no matter what,
people just can't eat that 175% the next day.
Most people eat around the 110%.
So just slightly over what they usually eat, actually.
You appear to be slowing down the ageing process,
or the diseases associated with it.
You're cutting the risks of the diseases associated,
-which is quite a profound thing to do.
Krista's research is still in the early stages.
But from what I've seen and experienced,
I am now starting to be won over
by the idea that a simple pattern
of feast and fast can be powerful.
It seems to have an impact which goes beyond simply eating less.
And I think it could work for someone like me.
My final stop is Baltimore.
I'm here because I need a final bit of motivation.
There's one aspect of ageing I find more terrifying than any other.
The effects of ageing on my brain.
I'm trying to catch up with Professor Mark Mattson.
Mark is a leading expert on the ageing brain.
His research suggests that fasting
may help delay the onset of diseases
like Alzheimer's, dementia, and memory loss.
-How you doing?
-Hi there! Michael Mosley.
-You work here?!
-Work here? No!
-Nor do I work out here!
OK, Michael. We need to put some booties on!
We're heading down into the basement
of the National Institute on Ageing.
Hidden away down here,
there's a special mouse he's keen to show me.
This mouse is exploring a maze.
It's a memory test, designed to see how well he remembers
where he has found food before.
-So the food is actually in there, is it?
-The food's in here.
The mice they study are destined to develop Alzheimer's disease.
Normally, they succumb within a relatively short time,
but when these mice are put on a diet
of feast days and fast days,
what Mark calls "intermittent energy restriction",
the results are incredible.
..So that the animals on intermittent energy restriction,
they'll live much longer with normal,
at least, as best we can test,
normal learning and memory, before they start having problems.
Yeah, highly significantly.
We found in one study, six months to a year.
That's the equivalent in a human of the difference between
developing signs of Alzheimer's at say, the age of 50,
-and the age of 80? Something like that? Is that right?
'On the other hand, when the mice eat a fast-food diet,
'they go downhill much earlier.'
-We give them...
-Lots of sugary drinks?
-A high-fat diet, exactly.
And we put fructose in their drinking water,
and that has a dramatic effect.
The animals will have an earlier onset
of the learning and memory problems.
How much sooner?
-Um, three to four months sooner.
So that is the equivalent of them developing Alzheimer's
-in their 30s or maybe early 40s?
So far, they've only done studies in mice,
but they're about to carry out human trials.
How good if the evidence that if someone like me
were to start on intermittent fasting,
it would cut my risk of brain disease, broadly?
I think, from the human standpoint,
if we go on a scale from poor to good to very good
to excellent to outstanding,
it's in the very good to excellent range.
That's the way I would categorise it.
So, what's going on?
Well, when they examined the brains of the fasting mice,
they found something extraordinary.
These green objects are newborn brain cells.
These three here are brand new?
Sporadic bouts of hunger actually trigger new neurons to grow.
Why should a brain start to generate
new nerve cells when you stop feeding it?
If you think about this in evolutionary terms, it makes sense
if you're hungry, you'd better increase your cognitive ability.
That will give you a survival advantage,
if you can remember where the location of the food is and so on.
It seems that fasting stresses your grey matter the way that exercise stresses your muscles.
-So hunger really does make you sharper?
-Yes. We think so.
Mark's research is starting to point towards a simple conclusion.
Alternate day fasting has better effects on the brain
than does a lower amount of daily calorie restriction.
It's true of mice, but he needs to do proper human trials to prove it's true in us.
I've come to the end of my search to find out how to eat, fast and live longer.
The official advice is, eat at least 2,000 calories a day,
and if you really want to fast, even on an intermittent basis,
see your doctor first, because there are people it could harm,
such as pregnant women or those who are already underweight.
I'm going to be cautious, and have decided to go with a pattern that Mark recommended.
Not alternate day fasting, but a less extreme five/two diet -
five days' normal eating, followed by two days' fasting, each week.
It's my last day in the States, and it has been absolutely eye opening.
I had no idea at all that there was so much research going on
into fasting, calorie restriction in all its forms, and sort of anti-ageing research.
I've decided now that I am definitely going to try the five/two diet,
that's five days' normal eating, then two days of 600 calories a day.
I really, really hope it makes a difference,
because I'm conscious now that I am really at the foothills
of what could be quite a steep advance into age,
and if there is something that could slow that ageing process down and give me
more years of healthy living, then I would really embrace that.
I'm heading home to the UK.
I've decided to give myself five weeks to get used to my new diet,
and see if I get results.
This is going to be one of my fasting days,
and I've decided I'm going to eat breakfast as my main meal.
Mark Mattson told me he doesn't think it matters
when you eat your calories on a fast day.
I've tried other things, but it is really quite discouraging
going into work when you're feeling hungry.
There's another reason I'm determined to try this regime.
When I arrived home, I had another IGF-1 test.
Annoyingly, my levels were higher than ever.
Turns out the hard-won effects of the four-day fast only lasted a short while.
And she's kind of running with it at the moment, I think.
'So I hope this is something I can stick to.'
Good. It's done. It's actually twenty to two,
and I don't feel remotely hungry, but it is lunchtime,
so if nothing else, I think I'm going to go and prowl around.
MUSIC: "Harder, Better, Faster, Stronger" by Daft Punk
I found that fasting when I'm busy at work was doable,
but the next big test is my holiday.
I'm walking with some friends.
We are doing a walk across the Trans-Pennine Way.
Had breakfast this morning about two hours ago,
and I'm planning on eating next breakfast tomorrow.
So far I am feeling quite good.
It's now about seven o'clock. Haven't eaten for about 12 hours.
The others are behind me in the pub eating,
so I decided to come outside for a bit, because...
I'm not as strong-minded as I thought I was.
My stomach is begin to rumble a bit, but it's all right.
'It's been five weeks since I started the five/two diet.'
Not very good dog!
'I managed to fit in two 600 calorie fast days each week,
'though they tended to be a bit scattered around.
'But has it been enough to make a difference?'
So, today's results day.
I have lost, I know, some weight,
I'll find out in a moment just how much, but I'm mainly interested
in the bloods, because five or six weeks ago they were pretty terrible.
I have high blood glucose, high cholesterol, high IGF.
And I'm really, really keen to see them improve,
because frankly, if they haven't improved, then I am in trouble,
and I do want to stay young and healthy for my family, for myself.
So, I'm quite anxious, because this matters an awful lot to me.
Just to remind you, this is what I looked like at the start of this film.
And this is me today.
I've had to add a few new holes to my belt,
so I know that something has changed, but by how much?
Right, the moment of truth, in which I discovered just how much weight I have lost.
These are a special type of scales which are going to measure my weight accurately,
but also, apparently, my body fat.
Hey! That is fantastic!
That is 173.8lb, which means I have lost well over a stone.
My body fat when we did it before was 27%,
and now it's below 20.
That is really, really pleasing.
I feel good, and my family say I look slimmer.
It really hasn't been that difficult,
and I'm delighted that I'm no longer in the overweight category.
But what I really want to know is what's changed inside my body.
Professor Luigi Fontana is about to call with my final results.
-Hi, Luigi, how are you?
-I'm fine, and you?
-I'm very good.
So, we've got your results.
Just by fasting two days a week, you made a great impact
on your cardiometabolic health, and so I'm very proud of you.
'But what's happened to my IGF-1? Is my body still in go-go mode?'
IGF-1 is the major risk factor for cancer.
Breast cancer, prostate cancer, colon cancer.
Both the three-and-a-half day fasting
and the five weeks' intermittent fasting dropped your IGF-1 by 50%.
'Which is enough to reduce my risk of certain cancers.
'But what about my blood sugar, which was borderline diabetic?'
-Your glucose dropped to 90.
So your glucose became normal again.
'My final result is cholesterol.'
So, you had a reduction in total cholesterol,
and in an increase in the good cholesterol.
This shows how little it takes, you know,
to improve without drugs, without taking medication.
'It wasn't THAT little an effort,
'but I have cut my risk of developing diseases which could shorten my life.'
Thank you. So, I should live happily ever after, should I?
I don't know if you're going to live happier,
but you have a lower risk of developing diseases.
-Thank you very much, Luigi, really, thank you.
I'm very, very pleased. Very pleased indeed.
That was far better than I was expecting.
'I wanted my wife Claire, who is a GP, to share my results.'
So, this is my IGF, which is kind of my cancer/ageing risk.
-This one's come down to half on the two-day fasting.
All of them have shown the improvement that you, kind of, hoped for.
That basically means you're not going to have to take tablets at all, at the moment.
-If you stick to it.
Well, you're looking good on it.
Thank you. No, I'm really pleased.
-I have to say that's really, amazingly good news.
The results have been absolutely fantastic for me,
but that doesn't mean that intermittent fasting will work for everyone.
It's really important that they do more trials on humans,
to find out if, in the long term, it is safe and effective.
But having experienced intermittent fasting, I plan to go on doing it.
It seems to have undone some of the damage
that I have done to my body down the years.
It is very poignant looking at the photographs of myself
and members of my family growing up and growing older,
but it doesn't make me want to hold back the hands of time.
I sort of think that we do grow old, we should grow old,
and there's very little we can do about it.
But fasting is somehow different. Fasting is not about trying to live to 140,
it's about staying healthy for as long as you can,
and with the sort of time bomb we're facing as a nation,
with obesity going up, diabetes going up,
we desperately need something which can make a difference.
Fasting is the first thing I've come across
that I genuinely believe that if people were to take it up,
it could radically transform the nation's health.
So, I hope that we continue to see massive research going into this territory.
Doing this fasting has been one of the most interesting...
no, I would say THE most interesting sort of journey, film,
whatever you want to call it, that I have been on.
And I've never said that before.
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