Horizon (1964–…): Season 48, Episode 12 - The Truth About Fat - full transcript
As a nation, we are slowly
but surely getting fatter.
We're all eating well.
Maybe too well.
I'm Gabriel Weston
and I'm a surgeon and writer.
I think this obesity problem
has become bad enough
to be called an epidemic
But it's a puzzling one.
Here's the mystery.
We all live in the same environment,
surrounded by delicious food 24/7.
But we're not all the same shape.
Some of us balloon, some of us
get a bit chubby,
and some of us just stay thin
What is it about this epidemic
that operates so randomly?
For the unlucky majority,
nothing seems to stop
the pounds piling on.
We ask patients to go away,
eat a little bit less food,
do more exercise, but it hasn't
worked for the last 2,000 years
and we need to really come up with
some better ideas right now.
It's tempting to see this epidemic
as a failure of willpower.
It's just something you want,
you need, you know? It's fat.
But the latest research
that I've seen
has forced me to change my mind.
I'm pretty shocked to discover
that my assumption of a lifetime,
which is that I'm the size I am
because of my character, is nonsense
And this new science may hold
important clues
for fighting the fat epidemic.
I've been working as a surgeon
for over ten years.
I love being in theatre.
I've always enjoyed it.
There hasn't been a week gone by
when I haven't loved being here,
and I can't completely explain
why I do, to be honest.
It's a chemical thing.
It's a great place to be.
I feel myself when I am here.
I specialize in skin operations.
Today, I'm removing small
but potentially dangerous growths.
Sore bit coming up now.
Well done.
If you feel anything sharp,
let me know and I'll give
you some more local.
We have a number of cases,
all of which are likely
to be skin cancer.
They are either of the type
that will just grow unless removed
or even the type that can spread
and kill people.
The feeling that my surgical skills
are helping to treat cancer
is really satisfying.
When I stick this knife into someone
and they've got a skin cancer,
I feel happy about what I am doing
and I enjoy it.
But there is one group of patients
we seem unable to help
as much as we'd like.
These are the growing number
of obese people
who are now coming in for surgery.
What we've been
doing on this operating theatre
this afternoon has been quick.
We've seen lots of surgical
patients really fast.
But in hospitals
all over the country,
obese patients are bringing
surgical operations
to a compete standstill.
They complicate the surgical process
at every level.
They have tons of other illnesses
which make their surgical
diseases complex.
They're extremely difficult to
anaesthetise
and difficult to operate on as well.
This makes surgery riskier
for thousands of patients every year
But it's not just
a problem in surgery.
I'm also a mother, so I'm concerned
how this explosion of obesity
will affect our children
and their children too.
What I want to do is look at some of
the interesting new research
that's trying to explain
what obesity is all about
and some of the ways
we might go about
fighting this fat epidemic.
On the face of it, there seems
an obvious reason
why the last 20 years
has seen our weight soar.
We're eating more food than we need,
because it's more easily available
than ever before.
I'll just try a little bit of this.
That is delicious.
Here in the modern developed world,
food is everywhere
and it's rich in calories.
Spicy sausage.
Mm, lovely. It's packed with
flavour.
Some estimates suggest that most of
us are now eating
over 200 more calories
than we need every day.
And the truth is it's the fatty,
calorie-rich foods we love the most
Wow! A Portuguese custard tart.
This is literally my favourite food
on earth. Here I go.
It's too good for words.
What I see at this market
is the collision
of two different worlds.
Our bodies evolved in a prehistoric
world where calories were scarce,
hence our love for the taste
of the fatty stuff.
But our developed world
is awash with food.
When our primitive biology feeds
so richly,
the result for many is obesity.
In fact, nearly a quarter of the
adult population
are now clinically obese.
So is there anything
we can do about it?
To answer this question,
I want to start by explaining
how the obesity epidemic is
actually doing us damage.
I want to talk about fat.
And as a surgeon, I can take a look
at fat from a unique perspective.
From the inside out.
I've come to
the Royal Veterinary College
to show you something
rather surprising.
This isn't exactly the kind
of anatomy I'm used to,
but it's as close to human
as I'm going to get.
Food is a biological necessity.
And at the most basic level,
fat is too.
It's just the body's way
of storing food between meals.
So fat is not all bad.
Now I'm cutting through
the epidermis,
the dermis, down onto
the hypodermis,
which is the subcutaneous fat.
It's quite hard work in a pig
compared to a human being.
This layer of white, dense
tissue here
is the subcutaneous fat
and this is one of the places where
this pig, as well as you and I,
store our fat.
Subcutaneous fat can do this
because it's made up
of billions of special cells
that are capable
of expanding and contracting.
So this fat is actually
protecting us
during periods of starvation
You might think that when a person
becomes overweight,
it's this stuff making them ill.
But actually subcutaneous fat
is not where the problem lies.
Now if I go deeper into
the pig's body,
I find a different, more dangerous
kind of fat.
I have to say that having not done
any dissection of anything dead
in over ten years,
it's a real pleasure
just to be able to dissect
a carcass like this.
What I'm looking for now
is something we call
visceral fat, which we've all
got some of.
OK, I'm in.
Oh, my goodness.
That is just too cool
This visceral fat, gathered around
the most sensitive organs,
accumulates when we eat more than
our bodies can handle.
There's lots of visceral fat here.
There's a bit of fat just coming
off the bottom of the liver there.
That's intra-abdominal fat.
Too much of this visceral fat can
lead to a surge in cytokines,
chemicals which have been linked
to diabetes and heart disease.
We can't live without fat,
with all the important roles it
performs. But if we overload it
so that it can't work
properly anymore,
we can't easily live with it either.
So, simply put, too much visceral
fat can make us sick.
Everyone knows that
how much fat you put on
starts with a few basic decisions.
What to eat.
When to eat.
How much to eat.
When to stop.
But what is it in our bodies that
is shaping these decisions?
And how can we control it?
I've come to meet Dr Carel Le Roux,
one of the world's leading
obesity scientists, who may have
come up with some of the answers.
He's a former athlete turned medic,
whose own life story
helped focus his work
So, what got you interested
in obesity to start with?
Obesity is such an important
disease at the moment.
There are so many people
suffering from it,
and yet we as doctors are not
able to help them.
We ask patients to go away,
eat a little bit less food,
do more exercise, but it hasn't
worked for the last 2,000 years
and we need to really come up with
some better ideas right now.
His work started with an interest in
what was controlling his own weight.
As a champion shot-putter,
he was continually trying
to bulk up.
But however much he ate,
he couldn't seem to gain as much
weight as he needed.
I was very motivated.
I had a lot of willpower.
I wanted to get my weight up but,
despite my best efforts,
my body would just not allow me to
get out of this set point
where it wanted me to be.
His group started to investigate
what process in our bodies
might be controlling
this set point in our weight.
And they started to look at some of
our body's chemical messengers
A group of proteins which course
through our body
every day, influencing
our behaviour.
They're our hormones.
Hormones tell the body
when to fight or to flee.
How to repair itself.
They even tell our cells
when to die.
Then ten years ago, Le Roux
was part of a research team
that made a startling breakthrough.
They discovered two new hormones,
ghrelin and PYY,
that together seemed to control
appetite and weight.
There was a hormone that
actually made us hungry.
In 2002, we discovered there was
a hormone that made us full.
how did the discovery
of these two new hormones
influence the science of obesity?
It completely opened up a new
chapter because for the first time,
we understood that the gut can
actually talk to the brain
and influence how hungry you are
or how full you are.
So now we understood why
it is so difficult
for patients who are overweight to
actually change their weight,
because these hormones work
against them.
I have to admit, I feel a bit
sceptical about this idea
that an overweight person
is overweight
because of their hormones, but I'm
not overweight because of mine.
Well, why don't we invite you
to come to the hospital?
We'll do an experiment where
we put your willpower
against your hormones
and see which comes out best.
Today I'm hoping to find out
how my hormones
might secretly be
controlling my appetite.
If Dr Le Roux can prove to me
that I am at their mercy,
I'll have to think again
about what's causing people
to over eat.
Can I take your coat? Yes, thank you
very much. Grab a seat.
Have you eaten anything?
I think the last time I ate anything
was 9pm yesterday evening.
All right. You're going to have some
breakfast. Eat as much as you want.
You'll have a spread, so you can
choose. I'm then going to take
some blood tests from you.
What we're going to determine
from the blood tests is how does
the gut talk to the brain.
It all starts simply enough
Somewhere in my blood
are my appetite hormones,
helping me to decide what to eat.
Oh my goodness, look at that.
It's a feast!
We also have something
in the microwave for you.
Ooh, that looks really delicious.
I think you've hit
the jackpot there.
I am now primed for the experiment.
Or at least I thought I was.
Well, we've tricked you
a little bit,
because what we're going to ask you
to do now is not to eat again
until breakfast tomorrow.
Wow, OK!
It's not what I was expecting. If
I'd known before,
and this is why you're telling me
now, I would have eaten double.
Your body will be able to cope with
the fast,
but it will actually psychologically
bring all types of things
to the fore.
Because, of course, if people
become hungry, they become ratty.
So the next 24 hours were
to be the battleground
where my hormones and my
willpower would fight.
After just a few hours
I notice my hunger returning,
and it begins to affect me.
I'm feeling very
distracted by how hungry I am.
I'm having to concentrate
a bit harder
on driving than I usually would.
Because I'm not feeling
that I can drive
quite as well as usual.
Later, I can feel
the changing hormones
really starting to alter my mood.
I'm feeling grumpy now
Really hungry actually.
So I feel as if I want to make
this as quick a visit as I can.
And my judgement too.
I'm going to stop
and get some yoghurts.
Ooh. I'm also feeling like
I'm looking at them and feeling
indecisive, which is not me at all.
And as I began to get
really hungry,
food was all I could think about.
Over here, they have the...
The smell is just powerful
and delicious.
They made the roast chickens there.
7am. Nearly 24 hours
since I last ate.
And just one hormone
measurement left
before I can give in to my hunger.
Morning! How are you?
I am ravenous. Really?
And a bit tired.
Well, let me take your coat and
let's get right into the experiment.
Dr Le Roux does the last blood
test and I can finally eat.
And I immediately tuck into
the sweetest, fattiest food
on the table.
And I'm going to have my first
bite of food in 24 hours.
It was quite possibly
the best meal of my life.
It's really, really good.
But what I'm really keen
to find out
is how my hormone results compare
to those of an obese persons.
Take a seat here.
The results are in
and the good news
is that you're completely normal.
Great! What we see
that immediately when you've had
your meal,
your hunger hormone starts falling
and then after a short period,
it starts
rising. And by the beginning
of the next morning,
it is incredibly high.
Which is exactly how I felt.
I was beside myself by then.
And how about the fullness hormone?
Looking at that,
you see the opposite.
Immediately when you eat,
the fullness hormone shoots up.
It makes you feel full,
allows you to stop eating.
And then it starts plummeting and it
stays down for the whole duration.
So how would that compare with
the profile of someone who had...
who was overweight or obese?
With the hunger hormone,
surprisingly,
obese patients didn't have as much
hunger as we expected.
The hunger hormone
never gets switched on
and it stays at the same level
throughout the day
and then starts rising
if we actually had to deprive
them of food.
So it's a little bit like
a light shining dimly
but where your light shines
brightly,
it gets switched off.
When they eat the light stays on.
So that constant nagging sensation
remains throughout the day.
Which is really interesting because
not knowing about this hormone,
what I expected
was that you would tell me
that someone who was overweight
had a much, much stronger
hunger hormone than I do
but in fact what you're saying
is that that's not the case.
You're right and we were surprised
until we looked at
the fullness hormones
and suddenly it started making sense
because what you would see in
somebody that is overweight,
their fullness hormone only rises
a small amount
and then comes down again.
So they actually never get
the feeling of fullness.
And you would hear that very often
speaking to people
who are overweight.
They'll say, "I'm not that hungry
but, when I start eating,
I can't stop."
I'm pretty shocked to discover
that my assumption of a lifetime,
which is that I am the size I am
because of my character,
is nonsense.
And it seems
from what you're saying,
as if I just have
a fortunate hormone set.
If your hormone levels
were different,
the battle would have been
much harder.
Had I been asked to starve
a minute longer,
I'm not sure I would have managed.
My hunger hormone
was so powerful
that it actually affected
my decision about what
and how much to eat.
You actually ate 170 calories more
than you would have done
in comparison to the previous day.
So not only did you
eat the wrong food,
you also ate more food in total.
And that's what happens to patients
who are overweight.
They don't feel full
after they've had a meal
and they have to consume
more food and the wrong food.
What it's brought home to me
is that obesity is not
just about will power.
Its also about our biology,
our hormones.
But that's not the end of the story.
This epidemic is clearly complex
with many other causes.
And I'm particularly interested
in what we can learn from genetics
because I can see that fat parents
often have fat kids.
And I want to find out
if there are clues here
to help us tackle
the problem of obesity.
There's a really interesting
group of people
who have found themselves
unexpectedly at the forefront
of this research
Our similarities - our voices,
height, eyes, teeth,
noses, dimples...
Dimples, I've got one here.
And I've got a dimple on this side.
Nature's own genetic experiment...
Birth marks
on the back of our necks.
And little freckles and moles
on our body in certain places.
..identical twins.
Feet, both flat. Oh, yes, very.
Meet Elaine and Liz.
For most of their lives, they have
lived within a mile of each other
and shared almost everything.
Oh, do you remember these pictures?
Yeah.
Oh, so cute.
I think we were similar. Very alike.
Yeah. Very alike there. Definitely.
We just did not want to have
our pictures taken.
And, like most identical twins,
as children
they were like as peas in a pod.
And this one is a school picture.
They couldn't tell the difference.
Not at all.
Watching these two it's clear
that the relationship between twins
is extraordinary.
There is just a special bond,
which you can't explain really.
Its just being together... Together.
Being together.
All the time, yeah. As one.
One, but... But separate.
..but separate.
And now Elaine and Liz
have found themselves
right at the heart
of obesity research.
For the last 20 years,
one man has been studying
thousands of identical twins.
For Professor Tim Spector,
twins are a fascinating experiment
because they can reveal
the difference between
what we inherit through nature -
the genes we are born with -
or nurture - the environment
we experience.
What is it about twins
that helps you
when you are looking at
heritability?
Twins are the best model in humans
of actually working out
what proportion of ourselves, our
traits or diseases are due to genes
or due to our environment,
because you compare identical twins
and non identical twins,
and the two types of twins
both sharing the same environment,
so only similarity in one group
compared to the other
must be due to their genes.
Spector's work with twins
convinced him
that nature - our genes -
was the most important factor
in causing a whole host of traits,
from freckles to height
and, as it turns out, weight.
But that was until he met
identical twins like Elaine and Liz.
Because, while they share
many traits...
Everything was virtually identical.
..there's one thing
that makes them rather different.
Say about a stone and a half.
I would say at least two and a half
stone. Yeah. Yeah. Definitely.
The sisters are what's known as
discordant twins.
And their very existence flew
in the face of all Spector's ideas.
It was a bit of a shock because
I'd spent 15 years of my life
trying to convince the rest of
the world that things are heritable
and I'm suddenly having to say,
"Hang on a minute, genes aren't
the whole story here, clearly,
"because these identical clones are
behaving very much more differently
than we thought they should do."
The question was, what was making
these twins so different in weight?
They had the same genes,
they shared the same environment.
So, like 99% of identical twins
they should have been
exactly the same weight.
What level have you got yours on?
No wonder! You've got yours on one,
mine's on three!
And it turns out Liz and Elaine
are not unique.
Over the last year Tim Spector
has discovered another two dozen
of these rare discordant twins.
Hello. I'm Gabriel,
lovely to meet you all.
I'm just bringing some coffees in.
I'm intrigued
to talk to these twins
to see how their identical genes
have made them into
these genetic paradoxes.
Maybe you could just tell me
a couple of things about
what is the same
and what is different about you.
Some are still so similar
its hard to tell them apart.
I'm Debbie. I'm Mary.
We very much like the same things,
don't we?
Out taste in clothes is similar.
Some look different and yet still
have that remarkable twin-ness.
I'm Angela. And I'm Irene
We both have the same kind of
silly sense of humour,
where we can see something
and nobody else understands it
and we just burst into
uncontrollable giggles.
And some seem more like
normal sisters than twins.
I'm Fiona. And I'm Jane.
We get on a lot better
now that we are a lot older,
but unfortunately we live
in different parts of the world.
Today, these twins are in London
so that Professor Spector
can start to work out
why they are the same but different.
You guys are special
because most identical twins
are very close in weight.
You're not. Basically,
That's the simple sort of...
You don't have to be so blunt.
THEY LAUGH
In the past we've always said that
things like putting on weight
or your height or whatever are
completely determined by your genes,
and yet you are walking examples
of how exactly
that's not completely true.
Spector is putting these discordant
twins through a barrage of tests,
painstakingly looking for clues
to how they end up so different.
He looks for subtle differences
in DNA between Liz and Elaine.
We're going to take this
bit of tissue from you
to see how it differs
between you and your sister.
And he even checks for
tiny DNA variations
in different parts of the same twin.
So we get your nail clippings.
And that's to get extra DNA
to see if the DNA in your nails
is different to that in your blood.
The answer to the puzzle
of why twins with the same genes
can be different weights
seems to be this.
Spector now believes it's not enough
just to have a gene,
it has to be activated
or switched on.
And the larger twin
had her fat genes switched on
where her thinner sister hadn't.
Something has switched in them,
has just switched some of their
genes from one position to another
and that has altered
what's happened to their metabolism.
And, because they are so similar,
our idea is that we can track down
what those chemicals are
and what those genes are
that are changed between the two.
This new science of how
the environment can switch
your genes on and off
is becoming more and more important
across modern medicine.
Its called epigenetics.
But the question now is,
what was causing these genes
to be switched on or off?
Spector has been looking for
something that sets one twin's
experience apart from the other.
I maybe got a bit more attention.
I had to go to hospital with our mum
so I suppose I had stresses early on,
didn't I? Yeah, yeah.
When do you think
the changes occurred or you noticed
any differences between you?
I think the changes happened
when she got married and moved away.
I was married
but I had family closer to me
and she didn't have any family
closer to her.
And I think that's possibly
when the change occurred.
I think that's probably when it did.
I'm just aware,
as we are talking to these ladies,
that there is so many things
that might go on at any one time
between the lives
of two different women.
How do we know that we are not just
randomly selecting factors
that could be confounded
by hundreds of other factors?
You are absolutely right
and taking one pair, a snapshot
of your life in retrospect,
which is full of false memories is
not a reliable way of doing science.
So none of what I'm saying will be
based on one or two twins stories
but only by doing this
systematically
across hundreds of twins
to see what the common factors are.
And Spector thinks he's seeing some
common factors in all his twins.
His theory is that stress
can create parallel
but different destinies.
What was interesting
was three out of the five pairs
did give us a story of how,
when they were put under stress,
they reacted differently.
For me, what's so exciting
about Spector's work,
is that if he can understand
what turns the fat switch on,
he might find a way
to turn it off again.
To stop obesity in its tracks.
I think it's very exciting
looking into that future.
We already know many of the genes
are responsible for obesity,
we're going to find hundreds
and thousands more,
but the key to this is
how we can change those genes.
What Professor Spector was saying
quite strongly to the twins today
was, "Even if something has happened
"to predispose one of you
to putting weight on,
"where the other one has been free
of that, this is not set in stone
"and you could do things,
although it might be difficult,
"which could reverse
whatever signal has taken place
"which has led to one of you
being fatter,
"and one of you being thinner."
It's strange to think
that some small event in your life
might change everything.
That tiny switches in your genes can
fine tune how much and when you eat
and how you body uses that food.
But it's not the only way
that our genes lead to obesity.
Today, I'm on my way to Southampton
to find out about an inspiring study
based on this new science
of epigenetics.
It's helping us understand what
might be making our children fat.
Professor Keith Godfrey
runs this ambitious survey.
Professor Godfrey. Really nice
to see you. Lovely to meet YOU.
Lovely to meet you too.
His study is ambitious
because it starts
before the child is even conceived.
I wonder if you can take me
right back to the beginning
where it all started.
Well, it all started
over 15, 20 years ago
when we began looking at how
a mother's diet before she conceives
might have lifelong effects
on the development
and the health of her offspring.
Other surveys have begun
during pregnancy
or have had modest information
before conception
but this is the world's first
of its kind.
These are some of the 12,000 women
who joined up over 15 years ago.
The survey aimed to answer
a single, huge question.
What were all the factors that might
make their children obese?
So, once a week for those...
Was it influenced by the diet
and lifestyle of the parents?
Five times a week.
And once a week for sausages...
..and no beans.
Was it shaped by the nine months
the baby spent in the womb?
Or was a child's weight
a result of its experiences
in the first years of its life?
OK, don't worry.
And then after 15 years
of searching, they found the answer.
It sounds like
an incredibly work-intensive job,
and what did it show?
We've shown that
the baby's development in the womb
influences its risk of obesity
six or nine years down the line
in childhood.
It was a completely new
cause of obesity.
It seems that the biggest single
factor causing a child to be fat
was the nine months it spent
in its mother's womb.
Amazingly, they explained something
like a quarter of the differences
between the children in their degree
of obesity nine years later.
This claim that a single cause adds
25% to the risk of childhood obesity
is enough to make any doctor
sit up and listen.
And in your experience,
is that a strong association?
We've never seen anything
as strongly related
to the child's obesity before.
In all the studies that we've
performed over the last 20, 25 years,
never anything quite like this.
So what was happening in the womb
that made this crucial difference?
Godfrey started to look at the genes
in the only tissue that links mother
to child within the womb itself.
The umbilical cord.
So these are the umbilical cords
that we've collected
and over 3,000 women
in the Southampton Women's Survey
have kindly agreed
that we could use their cord.
And how fresh is this specimen?
So this is a placenta and
umbilical cord from earlier today.
When he analysed the cord
he found something unexpected -
a single switch
on a gene called RXRA.
And it was powerfully linked
to childhood obesity.
And what controlled the setting
of this switch was this...
The mother's diet.
If the mother is undernourished
or eats an unbalanced
diet in pregnancy,
the baby thinks that
it's going to similarly
be undernourished after birth.
Those babies tend to be thin
at birth, but in our westernised
environments where there is
not much physical activity
and high food availability,
those children are mismatched
to that later environment
such that they progressively
put on fat during childhood.
So the nine months in the womb
turn out to be crucial
to your child's weight.
And with the right nutrition,
it's something we can change.
I think that this work holds
great promise for the future.
But right now the best health advice
hinges on exercise and diet,
and of course that's right.
But you just have to look around you
to see that its not enough.
So I'm interested in looking
at other ways that scientists
are thinking about tackling
our problem with fat.
I'm on my way to meet a woman
who is about to undergo what
I think is a fairly extreme
treatment for obesity.
But it's a treatment that might
have much wider implications.
Hi. Hi, I'm Gabriel.
I'm Marilyn, come in. Thank you.
Thanks for having me.
That's all right. Come through.
Marilyn Walsh is a mum who
lives in South London.
She weighs over 21 stone.
Four years old I was there.
Let's have a look, lovely.
Yes, but not, not thin,
look at the chubby cheeks.
What have we got here?
I'd be about 9, and you can
see the weight already.
Yeah? Yeah.
Like most overweight adults,
Marilyn has found that diets
have consistently failed.
And is this the stage
that you were telling me about,
where your mum was already putting
you on diets?
Yeah already, mum was already trying
with the diets, already, you know,
carrot sticks, cucumber sticks
at break time.
What these photos
are sort of painting a picture of
in a way is the sort of
lifetime of being overweight.
Yes, constantly having a weight
problem, you know, which it is,
it's a... it is a weight problem.
Why can't you just lose weight,
like why can't you just
not eat the things that are making
you put the weight on?
It would be a bit
like saying why can't an alcoholic
stop drinking. Why can't a smoker
stop smoking, it's exactly
the same answer you'd ask them.
There isn't, there isn't an answer,
it's... Something that's
been with me all my life.
And you just feel
hungry all the time?
I'm always hungry
and always wanting food.
Worst picture of all.
Biggest, I think, I ever was.
At the moment Marilyn is healthy,
but she know from her family the
sort of problems that may await her.
My uncle, my dad's brother,
he was I think about 35 stone,
suffered with weight
throughout his whole life -
leg problems, stopped walking.
Couldn't go anywhere,
couldn't get in a chair
so he had to sit on the floor. Wow.
He developed diabetes through
it and lots of other problems.
And he did die because of his weight.
Unless something radical
is done for her,
Marilyn is likely to face a future
of ill health and expensive
treatments.
But Marilyn is now part of an
experiment that might shed light
on how we might be able to change
appetite and fatness forever.
I've come back to Imperial to meet
up again with Dr Carel Le Roux.
Having convinced me
that hormones shape our appetite,
he now believes that one
particular kind of surgery
can fundamentally
change the levels of these hormones.
Surgery on the stomach -
what's called a gastric bypass.
Can you explain to me the mechanics
of gastric bypass surgery?
So let me explain it like this.
That's the oesophagus or the gullet,
this is the stomach
and this is the small bowel
and this is the large bowel.
What the surgeons do
is they cut the stomach
and they cut the small bowel.
So you are now left with
you're oesophagus normal,
you have now a small stomach,
so your stomach
goes from the size of your two
fists into the size of your thumb.
The rest of the stomach
remains in place
and the first 50cms of your
small bowel and that's why
it's called the stomach bypass
because we take the bottom
bit of the small bowel and connect
it to the small stomach
and now food is
bypassing the stomach
and the first part
of the small bowel.
Reducing the size of the stomach
obviously limits how much
a person can eat. But it has
a more unexpected effect too.
It also changes
the patient's behaviour.
So what you're saying is that in
this particular operation actually
seems to affect someone's
motivation to eat?
That's right,
the patients come
to us in clinic and say,
"Doctor where did the
surgeon do the operation,
"did they operate
on my tummy or did they
"operate on my head because
I don't feel hungry any more,
"when I do eat I feel full
and all these changes
"have really happened in my head."
This is a really
intriguing piece of research,
because it suggests a way
that we might be able to alter
one of the most fundamental drives -
appetite.
It's this operation that
Marilyn has been selected for.
Her doctors at Kings College
Hospital believe it's now the only
chance to save her from a future
of debilitating illness.
Hi Marilyn. Hello.
How are you today?
I'm Fine thank you.
Good. How are you feeling?
Excited, ready and waiting. Good.
Any concerns at all or just
looking forward to it
and everything it means?
Just looking forward
to the new journey.
Good. Right,
good luck with it,
I'm sure you won't need it.
The surgeon, Mr Ameet Patel has
allowed me to watch the procedure.
It's a controversial operation,
sometimes seen
as an expensive quick fix.
And until I made this film,
it was view that I shared.
When I was here ten years ago
working as a junior surgeon,
I have to confess I used to think
it was a very extreme measure
for patients to take
just because they were overweight.
In the old days
we'd make a cut here and here,
we'd get inside, do the operation,
it would be all open surgery.
Actually what we can do as an open
operation we're doing as
a keyhole now. And the recovery's
much better and quicker.
And I suppose the thing I see now
which I didn't see then is that for
a lot of patients this is the end of
a lot of things that they've tried.
Exactly, they want something
to change their lives...
and that's what it does,
it actually changes your life...
As its done by keyhole surgery
Mr Patel starts by making a series
of small incisions on the abdomen.
And as you can see
we're going through the layers...
And that's fat that we are looking
at the on the camera isn't it?
Yes. We're now going through
the...muscle layers.
And here we've got to
be a little bit careful as we
get into the abdominal cavity
without injuring anything.
Let's put the CO2 on for me.
So some gas is being what
we call insubflated through
the instrument here
and what that does is gives
a kind of expanded sort of tented
view of the anatomy he needs to see.
Its an operation that carries
rare but serious risks.
There is the stomach.
It's quite a big stomach,
you can see it all the way round.
This is all fat here?
This is all fat.
Resting on her stomach is a large
slab of visceral fat, the fat
that in excess can poison our organs
causing diabetes
and other diseases...
Before Mr Patel can connect
the small bowel to the bottom
of the stomach,
what he needs to do is create the
pouch which will be the new stomach.
Using a tool which
both staples and cuts,
he creates the new smaller stomach.
So that's the new stomach there.
And old stomach down here.
Old stomach on that side.
The operation usually
results in the patient's losing
a third of their weight
and keeping it off for at least
the next twenty years.
But if Dr Le Roux is right,
Marilyn won't lose weight just
because of her smaller stomach.
It'll be because the operation
has changed the way she thinks.
It's six weeks after the operation.
I really want to see what's
happened to Marilyn.
Hi!
So Marilyn, what are you wearing?
These are my trousers
from before the operation.
These are you pre-op trousers.
Look at that! Wow!
That's amazing,
that really is amazing.
But what I was really interested in
was how the operation
had changed her appetite.
Now perhaps after
a couple of table spoons
and I get a heavy
feeling in my stomach which
I presume is what you would class
as, I am full up now and I'll stop.
I can't eat any more.
I never had that before.
I just want to stop
and ask you a little bit
about the sorts of foods
that you used
to choose by preference,
and the sorts
that you would choose now?
I don't like the sweet or the fatty,
the fatty isn't appealing anymore.
So the two tastes that drove
you before, which were fatty
and sweet you now don't have
any interest in?
No, but the sweet, when I tasted
that hot chocolate last week
and the sweet it turned me,
it was awful.
And the fat on the roof
of your mouth, that was horrible,
trying to get rid of that
takes a long time.
For Marilyn, I hope this is
the beginning of much healthier
relationship with food,
one that will finally be sustained.
It's clear that
Marilyn's gastric bypass
hasn't just reduced her appetite,
It's completely altered her
relationship with food.
And doctors are discovering
this result again and again.
I really want to
know how this works.
How is it possible that an operation
conducted on someone's stomach
can be so radically altering
how their brain works?
I want to meet one of Dr le Roux's
colleagues who is studying
how gastric bypass surgery actually
changes patients' brains.
Dr Samantha Scholtz is a consultant
psychiatrist at Imperial College.
So what got you into obesity?
Well as a psychiatrist I'm
interested in human behaviour,
particularly the kind of behaviour
which drives a lot of
what we see every day.
And if you think about it,
there are not a lot
of stronger drivers
than food and seeking out food.
What's your specific
line of enquiry in obesity?
I was interested in how obese
people's brains
differed from people of
normal weight's brains.
And what kind of tools
were you able to use
for the science
of your investigation?
When I first started psychiatry
we didn't have a lot of tools
to see how the brain
actually functions
and as time has gone on
things like functional MRI
have become much more valuable.
Dr Scholtz is now using
new MRI techniques
to compare obese patient's brains
before and after
gastric bypass Surgery.
And today I am part
of her experiment.
First she shows me
a selection of high fat foods.
And the MRI scans my brain
for activity,
indicating my
subconscious desire for these foods.
Then I'm shown healthy foods.
And the MRI measures again.
It's actually quite unnerving
because with this machine,
you can't hide your feelings.
Later she shows me what she's found.
So you have some MRIs to show me.
This is the activity in your brain
or the areas that are lit up,
the red areas, the areas that
were more active when you were
looking at the pictures of high
calorie appetizing food.
High fat food was clearly having
very little effect on my brain.
This is a representative
MRI for someone of normal weight?
Yes, fairly representative
of that kind of picture.
On the other hand,
if we look at someone
who is just about to have
gastric bypass surgery
you can see
quite a big difference here.
So this is the obese
or overweight person's scan?
Yes this is activation in her brain
looking at exactly the same
pictures that you were. Wow.
You can see a big difference.
That's huge isn't it?
So you're seeing a lot of
activation in areas which
we know are associated with rewards
such as the orbital frontal cortex
but also area like the ventral
striata and amygdala
which we associate with addiction
and an emotional response to food.
The blue was revealing the obese
brain's deep desire for fatty food.
So the green is the same lady
after she has had gastric bypass
surgery about five months later.
The patient's brain response to
fatty food has now totally changed.
So it's really a striking
difference isn't it?
Yeah, I mean if we were to compare
this person's brain after
surgery to your brain,
so someone who is of normal weight,
we can see not
a lot of difference there.
I'm really impressed.
The operation seems
somehow to have pressed
the reset button in the brain.
I mean, this scan looks like you
have changed the brain
of a fat person into
the brain of a normal person.
In effect with bypass surgery
is changing someone's brain
fundamentally so their reaction
to seeing high-calorie food
is different and that would
ultimately drive their choices
of food so that they stop having
that battle with food that they
had before and are more like
someone like yourself
who doesn't have that
same battle with food.
Of course, surgery
is not the answer for everyone.
But if Dr Le Roux can find another
way to produce the effects
of the operation then he's found a
powerful new weapon against obesity
The next point
is maybe we can use devices -
we can put things into the bowel
that can mimic the operation.
Or we can use injections
or pills that actually will
do what the operations are achieving.
Now if we do that, that opens up
the whole science of obesity.
And this will allow us in five years,
ten years from now,
to have treatments that will have
incredible benefits to the masses.
Obesity is clearly
an incredibly complex issue
And one on which it is all too easy
to take the moral high ground.
It's linked to our genes...
our hormones...
even to our brains.
So merely saying
that it's a question of willpower
just isn't good enough.
And I've started to see that a new
set of answers is emerging
which might help us
to begin to defeat, what, to me,
is one of the defining
epidemics of our age.
Subtitles by Red Bee Media Ltd.
but surely getting fatter.
We're all eating well.
Maybe too well.
I'm Gabriel Weston
and I'm a surgeon and writer.
I think this obesity problem
has become bad enough
to be called an epidemic
But it's a puzzling one.
Here's the mystery.
We all live in the same environment,
surrounded by delicious food 24/7.
But we're not all the same shape.
Some of us balloon, some of us
get a bit chubby,
and some of us just stay thin
What is it about this epidemic
that operates so randomly?
For the unlucky majority,
nothing seems to stop
the pounds piling on.
We ask patients to go away,
eat a little bit less food,
do more exercise, but it hasn't
worked for the last 2,000 years
and we need to really come up with
some better ideas right now.
It's tempting to see this epidemic
as a failure of willpower.
It's just something you want,
you need, you know? It's fat.
But the latest research
that I've seen
has forced me to change my mind.
I'm pretty shocked to discover
that my assumption of a lifetime,
which is that I'm the size I am
because of my character, is nonsense
And this new science may hold
important clues
for fighting the fat epidemic.
I've been working as a surgeon
for over ten years.
I love being in theatre.
I've always enjoyed it.
There hasn't been a week gone by
when I haven't loved being here,
and I can't completely explain
why I do, to be honest.
It's a chemical thing.
It's a great place to be.
I feel myself when I am here.
I specialize in skin operations.
Today, I'm removing small
but potentially dangerous growths.
Sore bit coming up now.
Well done.
If you feel anything sharp,
let me know and I'll give
you some more local.
We have a number of cases,
all of which are likely
to be skin cancer.
They are either of the type
that will just grow unless removed
or even the type that can spread
and kill people.
The feeling that my surgical skills
are helping to treat cancer
is really satisfying.
When I stick this knife into someone
and they've got a skin cancer,
I feel happy about what I am doing
and I enjoy it.
But there is one group of patients
we seem unable to help
as much as we'd like.
These are the growing number
of obese people
who are now coming in for surgery.
What we've been
doing on this operating theatre
this afternoon has been quick.
We've seen lots of surgical
patients really fast.
But in hospitals
all over the country,
obese patients are bringing
surgical operations
to a compete standstill.
They complicate the surgical process
at every level.
They have tons of other illnesses
which make their surgical
diseases complex.
They're extremely difficult to
anaesthetise
and difficult to operate on as well.
This makes surgery riskier
for thousands of patients every year
But it's not just
a problem in surgery.
I'm also a mother, so I'm concerned
how this explosion of obesity
will affect our children
and their children too.
What I want to do is look at some of
the interesting new research
that's trying to explain
what obesity is all about
and some of the ways
we might go about
fighting this fat epidemic.
On the face of it, there seems
an obvious reason
why the last 20 years
has seen our weight soar.
We're eating more food than we need,
because it's more easily available
than ever before.
I'll just try a little bit of this.
That is delicious.
Here in the modern developed world,
food is everywhere
and it's rich in calories.
Spicy sausage.
Mm, lovely. It's packed with
flavour.
Some estimates suggest that most of
us are now eating
over 200 more calories
than we need every day.
And the truth is it's the fatty,
calorie-rich foods we love the most
Wow! A Portuguese custard tart.
This is literally my favourite food
on earth. Here I go.
It's too good for words.
What I see at this market
is the collision
of two different worlds.
Our bodies evolved in a prehistoric
world where calories were scarce,
hence our love for the taste
of the fatty stuff.
But our developed world
is awash with food.
When our primitive biology feeds
so richly,
the result for many is obesity.
In fact, nearly a quarter of the
adult population
are now clinically obese.
So is there anything
we can do about it?
To answer this question,
I want to start by explaining
how the obesity epidemic is
actually doing us damage.
I want to talk about fat.
And as a surgeon, I can take a look
at fat from a unique perspective.
From the inside out.
I've come to
the Royal Veterinary College
to show you something
rather surprising.
This isn't exactly the kind
of anatomy I'm used to,
but it's as close to human
as I'm going to get.
Food is a biological necessity.
And at the most basic level,
fat is too.
It's just the body's way
of storing food between meals.
So fat is not all bad.
Now I'm cutting through
the epidermis,
the dermis, down onto
the hypodermis,
which is the subcutaneous fat.
It's quite hard work in a pig
compared to a human being.
This layer of white, dense
tissue here
is the subcutaneous fat
and this is one of the places where
this pig, as well as you and I,
store our fat.
Subcutaneous fat can do this
because it's made up
of billions of special cells
that are capable
of expanding and contracting.
So this fat is actually
protecting us
during periods of starvation
You might think that when a person
becomes overweight,
it's this stuff making them ill.
But actually subcutaneous fat
is not where the problem lies.
Now if I go deeper into
the pig's body,
I find a different, more dangerous
kind of fat.
I have to say that having not done
any dissection of anything dead
in over ten years,
it's a real pleasure
just to be able to dissect
a carcass like this.
What I'm looking for now
is something we call
visceral fat, which we've all
got some of.
OK, I'm in.
Oh, my goodness.
That is just too cool
This visceral fat, gathered around
the most sensitive organs,
accumulates when we eat more than
our bodies can handle.
There's lots of visceral fat here.
There's a bit of fat just coming
off the bottom of the liver there.
That's intra-abdominal fat.
Too much of this visceral fat can
lead to a surge in cytokines,
chemicals which have been linked
to diabetes and heart disease.
We can't live without fat,
with all the important roles it
performs. But if we overload it
so that it can't work
properly anymore,
we can't easily live with it either.
So, simply put, too much visceral
fat can make us sick.
Everyone knows that
how much fat you put on
starts with a few basic decisions.
What to eat.
When to eat.
How much to eat.
When to stop.
But what is it in our bodies that
is shaping these decisions?
And how can we control it?
I've come to meet Dr Carel Le Roux,
one of the world's leading
obesity scientists, who may have
come up with some of the answers.
He's a former athlete turned medic,
whose own life story
helped focus his work
So, what got you interested
in obesity to start with?
Obesity is such an important
disease at the moment.
There are so many people
suffering from it,
and yet we as doctors are not
able to help them.
We ask patients to go away,
eat a little bit less food,
do more exercise, but it hasn't
worked for the last 2,000 years
and we need to really come up with
some better ideas right now.
His work started with an interest in
what was controlling his own weight.
As a champion shot-putter,
he was continually trying
to bulk up.
But however much he ate,
he couldn't seem to gain as much
weight as he needed.
I was very motivated.
I had a lot of willpower.
I wanted to get my weight up but,
despite my best efforts,
my body would just not allow me to
get out of this set point
where it wanted me to be.
His group started to investigate
what process in our bodies
might be controlling
this set point in our weight.
And they started to look at some of
our body's chemical messengers
A group of proteins which course
through our body
every day, influencing
our behaviour.
They're our hormones.
Hormones tell the body
when to fight or to flee.
How to repair itself.
They even tell our cells
when to die.
Then ten years ago, Le Roux
was part of a research team
that made a startling breakthrough.
They discovered two new hormones,
ghrelin and PYY,
that together seemed to control
appetite and weight.
There was a hormone that
actually made us hungry.
In 2002, we discovered there was
a hormone that made us full.
how did the discovery
of these two new hormones
influence the science of obesity?
It completely opened up a new
chapter because for the first time,
we understood that the gut can
actually talk to the brain
and influence how hungry you are
or how full you are.
So now we understood why
it is so difficult
for patients who are overweight to
actually change their weight,
because these hormones work
against them.
I have to admit, I feel a bit
sceptical about this idea
that an overweight person
is overweight
because of their hormones, but I'm
not overweight because of mine.
Well, why don't we invite you
to come to the hospital?
We'll do an experiment where
we put your willpower
against your hormones
and see which comes out best.
Today I'm hoping to find out
how my hormones
might secretly be
controlling my appetite.
If Dr Le Roux can prove to me
that I am at their mercy,
I'll have to think again
about what's causing people
to over eat.
Can I take your coat? Yes, thank you
very much. Grab a seat.
Have you eaten anything?
I think the last time I ate anything
was 9pm yesterday evening.
All right. You're going to have some
breakfast. Eat as much as you want.
You'll have a spread, so you can
choose. I'm then going to take
some blood tests from you.
What we're going to determine
from the blood tests is how does
the gut talk to the brain.
It all starts simply enough
Somewhere in my blood
are my appetite hormones,
helping me to decide what to eat.
Oh my goodness, look at that.
It's a feast!
We also have something
in the microwave for you.
Ooh, that looks really delicious.
I think you've hit
the jackpot there.
I am now primed for the experiment.
Or at least I thought I was.
Well, we've tricked you
a little bit,
because what we're going to ask you
to do now is not to eat again
until breakfast tomorrow.
Wow, OK!
It's not what I was expecting. If
I'd known before,
and this is why you're telling me
now, I would have eaten double.
Your body will be able to cope with
the fast,
but it will actually psychologically
bring all types of things
to the fore.
Because, of course, if people
become hungry, they become ratty.
So the next 24 hours were
to be the battleground
where my hormones and my
willpower would fight.
After just a few hours
I notice my hunger returning,
and it begins to affect me.
I'm feeling very
distracted by how hungry I am.
I'm having to concentrate
a bit harder
on driving than I usually would.
Because I'm not feeling
that I can drive
quite as well as usual.
Later, I can feel
the changing hormones
really starting to alter my mood.
I'm feeling grumpy now
Really hungry actually.
So I feel as if I want to make
this as quick a visit as I can.
And my judgement too.
I'm going to stop
and get some yoghurts.
Ooh. I'm also feeling like
I'm looking at them and feeling
indecisive, which is not me at all.
And as I began to get
really hungry,
food was all I could think about.
Over here, they have the...
The smell is just powerful
and delicious.
They made the roast chickens there.
7am. Nearly 24 hours
since I last ate.
And just one hormone
measurement left
before I can give in to my hunger.
Morning! How are you?
I am ravenous. Really?
And a bit tired.
Well, let me take your coat and
let's get right into the experiment.
Dr Le Roux does the last blood
test and I can finally eat.
And I immediately tuck into
the sweetest, fattiest food
on the table.
And I'm going to have my first
bite of food in 24 hours.
It was quite possibly
the best meal of my life.
It's really, really good.
But what I'm really keen
to find out
is how my hormone results compare
to those of an obese persons.
Take a seat here.
The results are in
and the good news
is that you're completely normal.
Great! What we see
that immediately when you've had
your meal,
your hunger hormone starts falling
and then after a short period,
it starts
rising. And by the beginning
of the next morning,
it is incredibly high.
Which is exactly how I felt.
I was beside myself by then.
And how about the fullness hormone?
Looking at that,
you see the opposite.
Immediately when you eat,
the fullness hormone shoots up.
It makes you feel full,
allows you to stop eating.
And then it starts plummeting and it
stays down for the whole duration.
So how would that compare with
the profile of someone who had...
who was overweight or obese?
With the hunger hormone,
surprisingly,
obese patients didn't have as much
hunger as we expected.
The hunger hormone
never gets switched on
and it stays at the same level
throughout the day
and then starts rising
if we actually had to deprive
them of food.
So it's a little bit like
a light shining dimly
but where your light shines
brightly,
it gets switched off.
When they eat the light stays on.
So that constant nagging sensation
remains throughout the day.
Which is really interesting because
not knowing about this hormone,
what I expected
was that you would tell me
that someone who was overweight
had a much, much stronger
hunger hormone than I do
but in fact what you're saying
is that that's not the case.
You're right and we were surprised
until we looked at
the fullness hormones
and suddenly it started making sense
because what you would see in
somebody that is overweight,
their fullness hormone only rises
a small amount
and then comes down again.
So they actually never get
the feeling of fullness.
And you would hear that very often
speaking to people
who are overweight.
They'll say, "I'm not that hungry
but, when I start eating,
I can't stop."
I'm pretty shocked to discover
that my assumption of a lifetime,
which is that I am the size I am
because of my character,
is nonsense.
And it seems
from what you're saying,
as if I just have
a fortunate hormone set.
If your hormone levels
were different,
the battle would have been
much harder.
Had I been asked to starve
a minute longer,
I'm not sure I would have managed.
My hunger hormone
was so powerful
that it actually affected
my decision about what
and how much to eat.
You actually ate 170 calories more
than you would have done
in comparison to the previous day.
So not only did you
eat the wrong food,
you also ate more food in total.
And that's what happens to patients
who are overweight.
They don't feel full
after they've had a meal
and they have to consume
more food and the wrong food.
What it's brought home to me
is that obesity is not
just about will power.
Its also about our biology,
our hormones.
But that's not the end of the story.
This epidemic is clearly complex
with many other causes.
And I'm particularly interested
in what we can learn from genetics
because I can see that fat parents
often have fat kids.
And I want to find out
if there are clues here
to help us tackle
the problem of obesity.
There's a really interesting
group of people
who have found themselves
unexpectedly at the forefront
of this research
Our similarities - our voices,
height, eyes, teeth,
noses, dimples...
Dimples, I've got one here.
And I've got a dimple on this side.
Nature's own genetic experiment...
Birth marks
on the back of our necks.
And little freckles and moles
on our body in certain places.
..identical twins.
Feet, both flat. Oh, yes, very.
Meet Elaine and Liz.
For most of their lives, they have
lived within a mile of each other
and shared almost everything.
Oh, do you remember these pictures?
Yeah.
Oh, so cute.
I think we were similar. Very alike.
Yeah. Very alike there. Definitely.
We just did not want to have
our pictures taken.
And, like most identical twins,
as children
they were like as peas in a pod.
And this one is a school picture.
They couldn't tell the difference.
Not at all.
Watching these two it's clear
that the relationship between twins
is extraordinary.
There is just a special bond,
which you can't explain really.
Its just being together... Together.
Being together.
All the time, yeah. As one.
One, but... But separate.
..but separate.
And now Elaine and Liz
have found themselves
right at the heart
of obesity research.
For the last 20 years,
one man has been studying
thousands of identical twins.
For Professor Tim Spector,
twins are a fascinating experiment
because they can reveal
the difference between
what we inherit through nature -
the genes we are born with -
or nurture - the environment
we experience.
What is it about twins
that helps you
when you are looking at
heritability?
Twins are the best model in humans
of actually working out
what proportion of ourselves, our
traits or diseases are due to genes
or due to our environment,
because you compare identical twins
and non identical twins,
and the two types of twins
both sharing the same environment,
so only similarity in one group
compared to the other
must be due to their genes.
Spector's work with twins
convinced him
that nature - our genes -
was the most important factor
in causing a whole host of traits,
from freckles to height
and, as it turns out, weight.
But that was until he met
identical twins like Elaine and Liz.
Because, while they share
many traits...
Everything was virtually identical.
..there's one thing
that makes them rather different.
Say about a stone and a half.
I would say at least two and a half
stone. Yeah. Yeah. Definitely.
The sisters are what's known as
discordant twins.
And their very existence flew
in the face of all Spector's ideas.
It was a bit of a shock because
I'd spent 15 years of my life
trying to convince the rest of
the world that things are heritable
and I'm suddenly having to say,
"Hang on a minute, genes aren't
the whole story here, clearly,
"because these identical clones are
behaving very much more differently
than we thought they should do."
The question was, what was making
these twins so different in weight?
They had the same genes,
they shared the same environment.
So, like 99% of identical twins
they should have been
exactly the same weight.
What level have you got yours on?
No wonder! You've got yours on one,
mine's on three!
And it turns out Liz and Elaine
are not unique.
Over the last year Tim Spector
has discovered another two dozen
of these rare discordant twins.
Hello. I'm Gabriel,
lovely to meet you all.
I'm just bringing some coffees in.
I'm intrigued
to talk to these twins
to see how their identical genes
have made them into
these genetic paradoxes.
Maybe you could just tell me
a couple of things about
what is the same
and what is different about you.
Some are still so similar
its hard to tell them apart.
I'm Debbie. I'm Mary.
We very much like the same things,
don't we?
Out taste in clothes is similar.
Some look different and yet still
have that remarkable twin-ness.
I'm Angela. And I'm Irene
We both have the same kind of
silly sense of humour,
where we can see something
and nobody else understands it
and we just burst into
uncontrollable giggles.
And some seem more like
normal sisters than twins.
I'm Fiona. And I'm Jane.
We get on a lot better
now that we are a lot older,
but unfortunately we live
in different parts of the world.
Today, these twins are in London
so that Professor Spector
can start to work out
why they are the same but different.
You guys are special
because most identical twins
are very close in weight.
You're not. Basically,
That's the simple sort of...
You don't have to be so blunt.
THEY LAUGH
In the past we've always said that
things like putting on weight
or your height or whatever are
completely determined by your genes,
and yet you are walking examples
of how exactly
that's not completely true.
Spector is putting these discordant
twins through a barrage of tests,
painstakingly looking for clues
to how they end up so different.
He looks for subtle differences
in DNA between Liz and Elaine.
We're going to take this
bit of tissue from you
to see how it differs
between you and your sister.
And he even checks for
tiny DNA variations
in different parts of the same twin.
So we get your nail clippings.
And that's to get extra DNA
to see if the DNA in your nails
is different to that in your blood.
The answer to the puzzle
of why twins with the same genes
can be different weights
seems to be this.
Spector now believes it's not enough
just to have a gene,
it has to be activated
or switched on.
And the larger twin
had her fat genes switched on
where her thinner sister hadn't.
Something has switched in them,
has just switched some of their
genes from one position to another
and that has altered
what's happened to their metabolism.
And, because they are so similar,
our idea is that we can track down
what those chemicals are
and what those genes are
that are changed between the two.
This new science of how
the environment can switch
your genes on and off
is becoming more and more important
across modern medicine.
Its called epigenetics.
But the question now is,
what was causing these genes
to be switched on or off?
Spector has been looking for
something that sets one twin's
experience apart from the other.
I maybe got a bit more attention.
I had to go to hospital with our mum
so I suppose I had stresses early on,
didn't I? Yeah, yeah.
When do you think
the changes occurred or you noticed
any differences between you?
I think the changes happened
when she got married and moved away.
I was married
but I had family closer to me
and she didn't have any family
closer to her.
And I think that's possibly
when the change occurred.
I think that's probably when it did.
I'm just aware,
as we are talking to these ladies,
that there is so many things
that might go on at any one time
between the lives
of two different women.
How do we know that we are not just
randomly selecting factors
that could be confounded
by hundreds of other factors?
You are absolutely right
and taking one pair, a snapshot
of your life in retrospect,
which is full of false memories is
not a reliable way of doing science.
So none of what I'm saying will be
based on one or two twins stories
but only by doing this
systematically
across hundreds of twins
to see what the common factors are.
And Spector thinks he's seeing some
common factors in all his twins.
His theory is that stress
can create parallel
but different destinies.
What was interesting
was three out of the five pairs
did give us a story of how,
when they were put under stress,
they reacted differently.
For me, what's so exciting
about Spector's work,
is that if he can understand
what turns the fat switch on,
he might find a way
to turn it off again.
To stop obesity in its tracks.
I think it's very exciting
looking into that future.
We already know many of the genes
are responsible for obesity,
we're going to find hundreds
and thousands more,
but the key to this is
how we can change those genes.
What Professor Spector was saying
quite strongly to the twins today
was, "Even if something has happened
"to predispose one of you
to putting weight on,
"where the other one has been free
of that, this is not set in stone
"and you could do things,
although it might be difficult,
"which could reverse
whatever signal has taken place
"which has led to one of you
being fatter,
"and one of you being thinner."
It's strange to think
that some small event in your life
might change everything.
That tiny switches in your genes can
fine tune how much and when you eat
and how you body uses that food.
But it's not the only way
that our genes lead to obesity.
Today, I'm on my way to Southampton
to find out about an inspiring study
based on this new science
of epigenetics.
It's helping us understand what
might be making our children fat.
Professor Keith Godfrey
runs this ambitious survey.
Professor Godfrey. Really nice
to see you. Lovely to meet YOU.
Lovely to meet you too.
His study is ambitious
because it starts
before the child is even conceived.
I wonder if you can take me
right back to the beginning
where it all started.
Well, it all started
over 15, 20 years ago
when we began looking at how
a mother's diet before she conceives
might have lifelong effects
on the development
and the health of her offspring.
Other surveys have begun
during pregnancy
or have had modest information
before conception
but this is the world's first
of its kind.
These are some of the 12,000 women
who joined up over 15 years ago.
The survey aimed to answer
a single, huge question.
What were all the factors that might
make their children obese?
So, once a week for those...
Was it influenced by the diet
and lifestyle of the parents?
Five times a week.
And once a week for sausages...
..and no beans.
Was it shaped by the nine months
the baby spent in the womb?
Or was a child's weight
a result of its experiences
in the first years of its life?
OK, don't worry.
And then after 15 years
of searching, they found the answer.
It sounds like
an incredibly work-intensive job,
and what did it show?
We've shown that
the baby's development in the womb
influences its risk of obesity
six or nine years down the line
in childhood.
It was a completely new
cause of obesity.
It seems that the biggest single
factor causing a child to be fat
was the nine months it spent
in its mother's womb.
Amazingly, they explained something
like a quarter of the differences
between the children in their degree
of obesity nine years later.
This claim that a single cause adds
25% to the risk of childhood obesity
is enough to make any doctor
sit up and listen.
And in your experience,
is that a strong association?
We've never seen anything
as strongly related
to the child's obesity before.
In all the studies that we've
performed over the last 20, 25 years,
never anything quite like this.
So what was happening in the womb
that made this crucial difference?
Godfrey started to look at the genes
in the only tissue that links mother
to child within the womb itself.
The umbilical cord.
So these are the umbilical cords
that we've collected
and over 3,000 women
in the Southampton Women's Survey
have kindly agreed
that we could use their cord.
And how fresh is this specimen?
So this is a placenta and
umbilical cord from earlier today.
When he analysed the cord
he found something unexpected -
a single switch
on a gene called RXRA.
And it was powerfully linked
to childhood obesity.
And what controlled the setting
of this switch was this...
The mother's diet.
If the mother is undernourished
or eats an unbalanced
diet in pregnancy,
the baby thinks that
it's going to similarly
be undernourished after birth.
Those babies tend to be thin
at birth, but in our westernised
environments where there is
not much physical activity
and high food availability,
those children are mismatched
to that later environment
such that they progressively
put on fat during childhood.
So the nine months in the womb
turn out to be crucial
to your child's weight.
And with the right nutrition,
it's something we can change.
I think that this work holds
great promise for the future.
But right now the best health advice
hinges on exercise and diet,
and of course that's right.
But you just have to look around you
to see that its not enough.
So I'm interested in looking
at other ways that scientists
are thinking about tackling
our problem with fat.
I'm on my way to meet a woman
who is about to undergo what
I think is a fairly extreme
treatment for obesity.
But it's a treatment that might
have much wider implications.
Hi. Hi, I'm Gabriel.
I'm Marilyn, come in. Thank you.
Thanks for having me.
That's all right. Come through.
Marilyn Walsh is a mum who
lives in South London.
She weighs over 21 stone.
Four years old I was there.
Let's have a look, lovely.
Yes, but not, not thin,
look at the chubby cheeks.
What have we got here?
I'd be about 9, and you can
see the weight already.
Yeah? Yeah.
Like most overweight adults,
Marilyn has found that diets
have consistently failed.
And is this the stage
that you were telling me about,
where your mum was already putting
you on diets?
Yeah already, mum was already trying
with the diets, already, you know,
carrot sticks, cucumber sticks
at break time.
What these photos
are sort of painting a picture of
in a way is the sort of
lifetime of being overweight.
Yes, constantly having a weight
problem, you know, which it is,
it's a... it is a weight problem.
Why can't you just lose weight,
like why can't you just
not eat the things that are making
you put the weight on?
It would be a bit
like saying why can't an alcoholic
stop drinking. Why can't a smoker
stop smoking, it's exactly
the same answer you'd ask them.
There isn't, there isn't an answer,
it's... Something that's
been with me all my life.
And you just feel
hungry all the time?
I'm always hungry
and always wanting food.
Worst picture of all.
Biggest, I think, I ever was.
At the moment Marilyn is healthy,
but she know from her family the
sort of problems that may await her.
My uncle, my dad's brother,
he was I think about 35 stone,
suffered with weight
throughout his whole life -
leg problems, stopped walking.
Couldn't go anywhere,
couldn't get in a chair
so he had to sit on the floor. Wow.
He developed diabetes through
it and lots of other problems.
And he did die because of his weight.
Unless something radical
is done for her,
Marilyn is likely to face a future
of ill health and expensive
treatments.
But Marilyn is now part of an
experiment that might shed light
on how we might be able to change
appetite and fatness forever.
I've come back to Imperial to meet
up again with Dr Carel Le Roux.
Having convinced me
that hormones shape our appetite,
he now believes that one
particular kind of surgery
can fundamentally
change the levels of these hormones.
Surgery on the stomach -
what's called a gastric bypass.
Can you explain to me the mechanics
of gastric bypass surgery?
So let me explain it like this.
That's the oesophagus or the gullet,
this is the stomach
and this is the small bowel
and this is the large bowel.
What the surgeons do
is they cut the stomach
and they cut the small bowel.
So you are now left with
you're oesophagus normal,
you have now a small stomach,
so your stomach
goes from the size of your two
fists into the size of your thumb.
The rest of the stomach
remains in place
and the first 50cms of your
small bowel and that's why
it's called the stomach bypass
because we take the bottom
bit of the small bowel and connect
it to the small stomach
and now food is
bypassing the stomach
and the first part
of the small bowel.
Reducing the size of the stomach
obviously limits how much
a person can eat. But it has
a more unexpected effect too.
It also changes
the patient's behaviour.
So what you're saying is that in
this particular operation actually
seems to affect someone's
motivation to eat?
That's right,
the patients come
to us in clinic and say,
"Doctor where did the
surgeon do the operation,
"did they operate
on my tummy or did they
"operate on my head because
I don't feel hungry any more,
"when I do eat I feel full
and all these changes
"have really happened in my head."
This is a really
intriguing piece of research,
because it suggests a way
that we might be able to alter
one of the most fundamental drives -
appetite.
It's this operation that
Marilyn has been selected for.
Her doctors at Kings College
Hospital believe it's now the only
chance to save her from a future
of debilitating illness.
Hi Marilyn. Hello.
How are you today?
I'm Fine thank you.
Good. How are you feeling?
Excited, ready and waiting. Good.
Any concerns at all or just
looking forward to it
and everything it means?
Just looking forward
to the new journey.
Good. Right,
good luck with it,
I'm sure you won't need it.
The surgeon, Mr Ameet Patel has
allowed me to watch the procedure.
It's a controversial operation,
sometimes seen
as an expensive quick fix.
And until I made this film,
it was view that I shared.
When I was here ten years ago
working as a junior surgeon,
I have to confess I used to think
it was a very extreme measure
for patients to take
just because they were overweight.
In the old days
we'd make a cut here and here,
we'd get inside, do the operation,
it would be all open surgery.
Actually what we can do as an open
operation we're doing as
a keyhole now. And the recovery's
much better and quicker.
And I suppose the thing I see now
which I didn't see then is that for
a lot of patients this is the end of
a lot of things that they've tried.
Exactly, they want something
to change their lives...
and that's what it does,
it actually changes your life...
As its done by keyhole surgery
Mr Patel starts by making a series
of small incisions on the abdomen.
And as you can see
we're going through the layers...
And that's fat that we are looking
at the on the camera isn't it?
Yes. We're now going through
the...muscle layers.
And here we've got to
be a little bit careful as we
get into the abdominal cavity
without injuring anything.
Let's put the CO2 on for me.
So some gas is being what
we call insubflated through
the instrument here
and what that does is gives
a kind of expanded sort of tented
view of the anatomy he needs to see.
Its an operation that carries
rare but serious risks.
There is the stomach.
It's quite a big stomach,
you can see it all the way round.
This is all fat here?
This is all fat.
Resting on her stomach is a large
slab of visceral fat, the fat
that in excess can poison our organs
causing diabetes
and other diseases...
Before Mr Patel can connect
the small bowel to the bottom
of the stomach,
what he needs to do is create the
pouch which will be the new stomach.
Using a tool which
both staples and cuts,
he creates the new smaller stomach.
So that's the new stomach there.
And old stomach down here.
Old stomach on that side.
The operation usually
results in the patient's losing
a third of their weight
and keeping it off for at least
the next twenty years.
But if Dr Le Roux is right,
Marilyn won't lose weight just
because of her smaller stomach.
It'll be because the operation
has changed the way she thinks.
It's six weeks after the operation.
I really want to see what's
happened to Marilyn.
Hi!
So Marilyn, what are you wearing?
These are my trousers
from before the operation.
These are you pre-op trousers.
Look at that! Wow!
That's amazing,
that really is amazing.
But what I was really interested in
was how the operation
had changed her appetite.
Now perhaps after
a couple of table spoons
and I get a heavy
feeling in my stomach which
I presume is what you would class
as, I am full up now and I'll stop.
I can't eat any more.
I never had that before.
I just want to stop
and ask you a little bit
about the sorts of foods
that you used
to choose by preference,
and the sorts
that you would choose now?
I don't like the sweet or the fatty,
the fatty isn't appealing anymore.
So the two tastes that drove
you before, which were fatty
and sweet you now don't have
any interest in?
No, but the sweet, when I tasted
that hot chocolate last week
and the sweet it turned me,
it was awful.
And the fat on the roof
of your mouth, that was horrible,
trying to get rid of that
takes a long time.
For Marilyn, I hope this is
the beginning of much healthier
relationship with food,
one that will finally be sustained.
It's clear that
Marilyn's gastric bypass
hasn't just reduced her appetite,
It's completely altered her
relationship with food.
And doctors are discovering
this result again and again.
I really want to
know how this works.
How is it possible that an operation
conducted on someone's stomach
can be so radically altering
how their brain works?
I want to meet one of Dr le Roux's
colleagues who is studying
how gastric bypass surgery actually
changes patients' brains.
Dr Samantha Scholtz is a consultant
psychiatrist at Imperial College.
So what got you into obesity?
Well as a psychiatrist I'm
interested in human behaviour,
particularly the kind of behaviour
which drives a lot of
what we see every day.
And if you think about it,
there are not a lot
of stronger drivers
than food and seeking out food.
What's your specific
line of enquiry in obesity?
I was interested in how obese
people's brains
differed from people of
normal weight's brains.
And what kind of tools
were you able to use
for the science
of your investigation?
When I first started psychiatry
we didn't have a lot of tools
to see how the brain
actually functions
and as time has gone on
things like functional MRI
have become much more valuable.
Dr Scholtz is now using
new MRI techniques
to compare obese patient's brains
before and after
gastric bypass Surgery.
And today I am part
of her experiment.
First she shows me
a selection of high fat foods.
And the MRI scans my brain
for activity,
indicating my
subconscious desire for these foods.
Then I'm shown healthy foods.
And the MRI measures again.
It's actually quite unnerving
because with this machine,
you can't hide your feelings.
Later she shows me what she's found.
So you have some MRIs to show me.
This is the activity in your brain
or the areas that are lit up,
the red areas, the areas that
were more active when you were
looking at the pictures of high
calorie appetizing food.
High fat food was clearly having
very little effect on my brain.
This is a representative
MRI for someone of normal weight?
Yes, fairly representative
of that kind of picture.
On the other hand,
if we look at someone
who is just about to have
gastric bypass surgery
you can see
quite a big difference here.
So this is the obese
or overweight person's scan?
Yes this is activation in her brain
looking at exactly the same
pictures that you were. Wow.
You can see a big difference.
That's huge isn't it?
So you're seeing a lot of
activation in areas which
we know are associated with rewards
such as the orbital frontal cortex
but also area like the ventral
striata and amygdala
which we associate with addiction
and an emotional response to food.
The blue was revealing the obese
brain's deep desire for fatty food.
So the green is the same lady
after she has had gastric bypass
surgery about five months later.
The patient's brain response to
fatty food has now totally changed.
So it's really a striking
difference isn't it?
Yeah, I mean if we were to compare
this person's brain after
surgery to your brain,
so someone who is of normal weight,
we can see not
a lot of difference there.
I'm really impressed.
The operation seems
somehow to have pressed
the reset button in the brain.
I mean, this scan looks like you
have changed the brain
of a fat person into
the brain of a normal person.
In effect with bypass surgery
is changing someone's brain
fundamentally so their reaction
to seeing high-calorie food
is different and that would
ultimately drive their choices
of food so that they stop having
that battle with food that they
had before and are more like
someone like yourself
who doesn't have that
same battle with food.
Of course, surgery
is not the answer for everyone.
But if Dr Le Roux can find another
way to produce the effects
of the operation then he's found a
powerful new weapon against obesity
The next point
is maybe we can use devices -
we can put things into the bowel
that can mimic the operation.
Or we can use injections
or pills that actually will
do what the operations are achieving.
Now if we do that, that opens up
the whole science of obesity.
And this will allow us in five years,
ten years from now,
to have treatments that will have
incredible benefits to the masses.
Obesity is clearly
an incredibly complex issue
And one on which it is all too easy
to take the moral high ground.
It's linked to our genes...
our hormones...
even to our brains.
So merely saying
that it's a question of willpower
just isn't good enough.
And I've started to see that a new
set of answers is emerging
which might help us
to begin to defeat, what, to me,
is one of the defining
epidemics of our age.
Subtitles by Red Bee Media Ltd.