Horizon (1964–…): Season 45, Episode 8 - Why Are Thin People Not Fat? - full transcript
The world is affected by an obesity epidemic, but why is it that not everyone is succumbing? Medical science has been obsessed with this subject and is coming up with some unexpected answers. As it turns out, it is not all about e...
I just wanted to show you my
originally fairly slim abdomen,
something like this,
and now look at it.
That is disgusting.
Ten people are about to find out
just how fat they can get.
It's just filthy.
Thanks to Horizon,
they're going to spend four weeks
eating more than
they've ever done before
of all the foods we're always
being told to avoid.
Oh, my God!
This month of gluttony
is all to answer a question
that science has struggled
with for 40 years.
The fight against fat
is being lost all over the world.
Britain's children are
facing an obesity time bomb.
Obesity is now so rife
that it has brought about
an evolutionary change
in the human body shape.
We're all going to become fat.
Low-besity, that's the new word.
The full extent of Britain's
obesity crisis
is revealed in a
new government report.
Inside this London cafe,
we've brought together ten members
of a rapidly disappearing part
of the UK population.
Unlike the 15 million of us
who are dangerously overweight,
these people are all...
slim.
The question they're here
to help us answer
is how they managed to stay that way,
despite most of them
never having dieted in their life.
I've always eaten whatever
I wanted to eat,
and my weight's always been very
stable and I've always been quite slim.
I'm really lucky and my friends hate me.
I'm constantly on a diet.
It's called the "see food" diet.
I see food and I eat it.
I eat a fair amount of food,
but my weight stays quite constant,
so I thought it would be interesting
to participate in this.
So what's their secret?
The field of obesity research
is stuffed full of studies
examining those who are
already overweight.
But recently, an expanding
number of scientists
have decided it's time
to take a closer look
at the skinnier ones amongst us.
I've always been
interested in people
claiming that they can't get fat
even though they eat a lot.
99.9% of studies today on obesity is
really made on already obese people,
and doesn't really give you any
reasons for why people get obese.
We need to figure out some way
to avoid obesity,
and why not try to learn something
from those that apparently
can't get obese.
Swedish scientist Professor
Fredrik Nystrom has come up
with an experiment to investigate
how different people's bodies cope
when they eat a lot more
than they need to.
Over the next four weeks,
our brave volunteers will be eating
double their normal number of
calories and doing no physical exercise.
It's a regime guaranteed to
induce significant weight gain
in even the slimmest person.
At least, that's what you'd assume!
But 40 years ago,
a group of American scientists
carried out a little-known study,
and their incredible findings
suggest otherwise.
Their story begins in the
most unlikely of places.
In 1967, the inmates
of the Vermont State Prison
were approached by
medical researcher Ethan Sims
to take part in a unique experiment.
He wanted to find out about the
hormonal changes in our bodies
when we become seriously overweight,
and in order to study that,
he needed to take a group
of people and make them fat,
very fat.
The study called for each inmate
to gain 25% of their body weight.
In return, they were promised
early release from jail.
Over the course of the year the team
fed the volunteer prisoners as much
as they could physically eat,
and carefully monitored their
bodily changes, but as it went on,
Dr Sims became concerned
by an unexpected finding.
However much they ate,
some of the prisoners
could not reach the target.
Two of the prisoners
got stuck at 21%,
and one of them couldn't put any
more than 18% extra body weight
despite eating as much
as 10,000 calories a day.
The experiment pointed to a
fascinating and unexpected conclusion.
It seemed that for some people,
becoming obese is not just unlikely,
it's practically impossible.
For years Sims' results have
remained the subject of fierce debate.
Could it be true that some people
really can eat as much as they want
without becoming obese?
And if so, how do they do it?
Good evening, everyone,
and welcome to Horizon's
over-feeding experiment.
Before we all get started, we want
to show you how much food you are
expected to eat for a typical week.
So if you help me to remove these...
The food on the table
corresponds to 35,000 calories
which then should give you
5,000 calories a day,
which is what the typical male
in this study is expected to eat.
That's a lot of food.
I think I might run home.
LAUGHTER
It's quite scary, it's quite scary.
It's quite shocking, the volume and the
drinks, the milk shakes and things like that.
It made me feel sick
just looking at it.
It's quite horrifying.
Having seen all
the food here today,
I think it's going to be a lot
harder than I envisaged before.
Obviously it's a bit daunting,
but I reckon it's deceptive.
I reckon if, you know,
you spooned it into days
rather than just all these plates
here, I reckon it would look fine.
I reckon I can take that.
If the Vermont prison
experimenters were right,
there could be
surprising differences
in how the bodies of the volunteers
respond to their new diet.
Some might fail
to put on much weight at all
and, at the other end of the scale,
there's a chance that someone
may have to leave the study
before the four weeks is up.
The upper limit of the increase
in body weight in this experiment
will be 15%.
It's not ethical
to go any further than that.
If anybody increases 15%, they're
going to be taken out of the study.
The average weight of our
volunteers is around 63kg.
An increase in body weight of 15%
would mean nearly ten extra
kilograms, or one and a half stone.
For the women, this could mean going
up two dress sizes in four weeks.
People are quite horrified
that a girl's doing it.
They can understand
why guys might do it,
and sort of get to eat
as much as they want,
but no-one seems to get why
a girl would want to get fat.
During the experiment,
we're going to keep track
of the participants' weight,
and carry out a series
of medical tests on them.
The aim is to uncover some clues
as to how they manage to stay slim
in an increasingly fat world.
Not that fat is
necessarily a bad thing!
At least, that's what
Dr Philipp Scherer believes.
He has devoted his career to
studying this much-maligned substance.
So what we're looking
at here is a rather
large piece of bovine fat, from a cow, obviously,
and if you look at
fat tissue from humans,
that would look exactly the same way.
So this is the tissue
that has a really bad reputation,
but fat is a really
marvellous substance,
and has a lot of really
wonderful qualities to it.
When it comes to fat,
all most of us want to do
is get rid of it
as quickly as possible.
We don't stop to think about
what our fat does for us.
Inside this fat tissue,
we've got billions and billions
of little fat cells,
and each one of these fat cells
has an oil droplet stored,
and if the body is in need of energy,
it can burn this oil
in a chemical reaction.
The energy contained
inside these cells
can keep us going
when food supplies are scarce.
Our fat is our body's
built-in emergency rations.
There is in fact a pretty wide range
within the human population
in terms of how much fat
each one of us carries around.
There are those that are
seriously overweight,
and some of those can actually...
have up to 100 times the amount
of fat that you see in this bowl.
And the more fat we have,
the longer we can keep going
without eating,
as one Scottish PhD
student found out.
the longer we can keep going
without eating,
as one Scottish PhD
student found out.
In 1968, she began conducting
an experiment on a 450lb man
who was desperate
to lose some weight.
He agreed to begin fasting
under her medical supervision,
and stopped eating or drinking
anything but water and vitamins.
Eventually he managed to
lose 275 pounds in weight.
He had lasted an incredible year
and two weeks without food.
But even a slim person can live off
their fat for several weeks.
The average lean individual probably
has about ten times the amount of fat
that you see in this bowl,
and it makes you wonder,
where are we putting it all?
What this means is
the average individual
can easily keep going
for more than a month.
In today's world, of course, we
never need to go without food
for anything like
as long as a month.
In fact, we are unlikely to have
to last more than a few hours.
But that wasn't the case
for most of human history.
According to obesity
geneticist, Dr Eric Ravussin,
our hunter-gatherer ancestors
had to live off
whatever they could find.
Sometimes that wasn't much,
which is when fat
as an efficient storage system
really came into its own.
Populations went through
periods of feast and famine.
During the periods of famine,
maybe two-thirds or three-quarters
of the population would disappear.
But those who were chubbier
or those fatter babies
would survive and then procreate
themselves and pass on these genes.
So according to this theory,
at times of famine,
it was literally a case
of the survival of the fattest.
The cycles of feast and famine that
humankind has been subjected to
was an important natural selective
process in which all the babies
or the people who were
a little bit chubbier
would survive the periods of famine,
and then be able to gain the
weight during the period of feast.
This could explain why large parts
of the population
have a tendency to lay down
fat stores easily.
It's only very recently
in human history
that this has become a problem.
Now the feast is constant,
you have food available every corner,
very cheap, very palatable and this
is really a perfect mixture
to provide the expression
of these genes
and confer obesity and
weight gain to these people.
And I think that this stigmatising
of the obese population is wrong,
because those were the survivors,
those are the people
who would survive
a difficult and tough environment.
But although putting on fat easily
may have been an advantage
in the past,
in today's environment,
the opposite is true.
It's the naturally slim who
live longer, healthier lives.
It's the day before our
volunteers begin their four weeks
of over-feeding, and they've come
to the University of Westminster
for some tests.
Every inch of their slim physiques
will be scrutinised.
OK, a sharp scratch coming up.
Ania Kosicka will be carrying
out the various tests.
And clinical obesity specialist,
Dr Carel le Roux
is overseeing the experiment.
He will be monitoring the
health of the volunteers throughout.
You have not increased much.
It's gone from 48kg to...
Determining how much body fat
they currently have
involves the space-age Bodpod...
BODPOD VOICE:
"Welcome to the Bodpod."
..a shower cap...
Quite how this is going to work,
I don't know.
..and no clothes.
What this measurement does
is it actually looks at
the air that's been displaced
by the body.
HE TAKES DEEP BREATH
And by using the patient's age,
gender, as well as weight,
we can actually calculate
how much of his body is fat
and how much of his body is muscle.
OK, so your percentage body
fat is 7.6.
Which puts you in the
ultra-lean category, OK?
According to the Bodpod,
hospital administrator Leo Dennett
has the lowest percentage
body fat of all the participants.
And medical students
Catherine Hannon
and Victoria Pagner have the most.
In both their cases, fat makes up
at least 20% of their body.
What we saw today in the volunteers
is that the men had half the amount
of fat than the women,
and that is what we would expect
in the general population.
For the purposes of the experiment,
each volunteer's normal daily
calorie requirement
For the purposes of the experiment,
each volunteer's normal daily
calorie requirement
has been calculated
taking into account
their physiological statistics.
These individual figures
have then been doubled
to work out how much each
of them will be eating
over the next four weeks.
They're also banned
from doing any physical exercise
that could skew the results.
They're also going
to carry pedometers
so that we can keep track of
the amount of steps that they make,
and we ask them not to walk more
than 5,000 steps a day,
so that we can keep track of
the amount of steps that they make,
and we ask them not to walk more
than 5,000 steps a day,
which roughly corresponds
to something like two miles.
For many of the volunteers,
the tension is building
as they face up to what lies ahead.
I'm actually very nervous now,
because tomorrow morning
I've got to eat a huge breakfast,
a massive, massive fry-up and,
and there's not going to be enough
time in the day, I think,
to fit in all this eating!
I was definitely looking
at fat people on the tube...
with a bit of apprehension, but I'm
pretty sure that I doubt that
I'll go anything above like...
..what, 73, something like that.
I think I've got it under control.
Many of us are concerned
by the slightest change
when we step on the bathroom scales.
But New Yorker Dr Rudy Leibel
is surprised that our weight
doesn't fluctuate a lot more.
One of the remarkable aspects
of human body weight
actually is how stable it is
over relatively long periods of time.
So for example the average adult
between the ages of 20
and 50 or 60 years of age
may gain 20 or 30 pounds.
But when you do the maths on this,
it's as little as seven extra
calories or ten extra calories
of food a day, which works
out to a potato chip or a French fry.
It seems that most of us
stay the same weight
for the whole of our adult lives,
apart from a slow
middle-aged spread.
But if all that was
affecting it was diet,
we'd have to be controlling the
number of calories we eat
to within seven calories a day.
We don't think that a human could
consciously control their body weight
to that level of precision.
Instead Dr Leibel believes
that we all have
a biologically-determined
natural weight
which varies from person to person,
and our bodies do their best
to maintain us at that weight,
be it fat or thin.
That doesn't mean that you cannot, by
over-eating consciously or responding
to delicious meals that
are in the environment,
or for example undertaking a
conscious effort to exercise a lot,
can't move this around a little bit,
but the body will constantly tend to
try to bring you back to whatever
your normal body weight is.
So if we're all stuck
with a natural weight,
what determines it,
and how early in life is it set?
According to Dr David Allison,
even events that take place
before we are born
whilst we are still in the womb
can affect the size we are destined
to become as adults.
There's now clear and emerging lines
of evidence indicating that several
factors can have long-term effects
on obesity and degree of body fatness
throughout life, even when those
effects occur in the womb.
We know that, for example,
older sheeps have fattier lambs,
and we know that older women,
women who give birth at a later age,
tend to have children that are more
likely to be overweight or obese.
And it seems that the mother's
weight and nutrition
during pregnancy are also crucial.
We also know that a mother that
is overfed or obese or diabetic
at certain portions of the pregnancy
will produce offspring
that have a greater probability of
themselves being overweight or obese.
There are a host of other
possible influences
including environmental factors,
even pollution.
Scientists are only just beginning
to uncover the many things
that may predetermine our weight.
But the message is clear.
It seems our size is much less under
our control than we might believe.
Day one.
I've eaten today
two chocolate croissants,
a lot of Crunchy Nut
and milk, pork pie,
a whole pizza with mayonnaise,
bottle of smoothie,
tub of ice cream, Ben and Jerry's
Phish Food,
couple of burgers
and some vegetables, um...
but I did cheat because
I kind of vomited once.
Um...it's pretty difficult.
Felt pretty ill most of the day.
Two pork pies.
Jaffa Cakes.
A large Quarter Pounder
Cheese meal
with strawberry milk shake
and a McFlurry.
Then another pork pie.
A melt-in-the-middle chocolate
pudding with cream...ha-ha-ha!
Chicago Town deep dish pizza
which is "made to share",
which is probably why
it's 1,240 calories.
Pizza with lots of mayonnaise.
Half a cheesecake
and a litre of Coke.
A sausage roll has 90% of the
calories of a Mars Bar.
A whole tub of Ben and Jerry's
with golden syrup.
McDonalds again for breakfast.
Pork pie. Yeah. Another pork pie.
Pate and asparagus,
in a sort of...melange.
Chocolate pudding with cream,
washed down with
a litre and a half of Coke.
To be honest I've hardly
stopped eating all day.
And I've had some of the kind of
most calorific food known to man,
and I've been full all day,
and I'm still nowhere near my target.
I think I went into this thinking
it would be easier than it is,
and I felt sick,
I feel...I feel disgusting.
This lack of exercise is killing me,
I mean, not being able to walk
is driving me mad.
I have a kind of a constant
sickly sweetness taste in my mouth.
Try and get it off.
I did discover that McDonalds doesn't
fill you up at all,
it has loads of calories in,
which is good.
And beer has a lot of calories in.
I thought Guinness would be a lot,
but Guinness is actually less than
most lagers, which is surprising.
OK, so this is the end of day six.
Tomorrow is our first weigh-in.
I'm really interested to see
how much weight
I'm going to have put on.
At the week one weigh-ins,
there's a surprise in store
for one of the participants.
OK, hello, Thomas!
Hello!
Thomas? Yes.
Your weight last week was 68.3kg.
Thomas? Yes.
Your weight last week was 68.3kg.
This week, it's 71.1kg.
So there's about 3kg increase,
and your percentage body fat
was 14% last week,
and this week it's 16.2.
I guess I'm putting the weight on
where it matters.
I don't know. I guess,
I guess I kind of expected that
to happen, but not quite as fast.
I'm a bit intrigued about
what it's going to be like
next week, third week, fourth week,
because I can expect
it to get worse...
So...trousers, that's a worry.
I'm a big man for tight trousers.
Must do some shopping.
2.8kg is equivalent to 4.1% of
Thomas's original body weight.
It's the highest percentage increase
out of the group.
The moment of truth.
In second place is Leo
Dennett on 3.2%.
The percentage body fat
today is 10.4. Oh, right.
So we have about 3.2% increase. OK.
It's quite a lot in one week.
Yeah, I'm not surprised, really,
to be honest.
According to the Bodpod,
he's gained so much new fat he's
moved out of the ultra-lean category
whereas both Aisha Rashid
and Martin Wong
have only gained a paltry
1.6% body weight.
It's almost like a mini-competition.
I'm aiming to either have to get
withdrawn from this
by putting on so much weight,
or turn up on the last day going,
"Yeah, I've been eating loads
and I'm still hungry."
BODPOD: "Welcome to the Bodpod,
please open the door." Stylish!
So, just one week in and already
there are striking differences
in weight gain
amongst the volunteers.
Look at the results...
Doubling your normal
number of calories
does not affect everyone
in the same way.
So I've put on one kilo,
but 5% more fat. Yes.
But the biggest surprise
for many of the volunteers
is how hard it has been
to eat double their
normal number of calories.
It does get really sickening,
like waking up at...
5am to eat chocolate peanuts!
You start off feeling terrible
and so you can't eat,
you can't eat so you get behind,
and it makes you feel terrible,
and you think that to feel un-terrible
you should force yourself to eat.
That makes you
feel more terrible,
and you end up missing a meal,
and end up losing more calories
than you made up by forcing
the snacks down yourself,
and you just feel more terrible,
and before you know what's happened,
it's 7pm and you're like...right!
Eff today, I'm starting
again tomorrow.
As their food diaries reveal,
our volunteers are all finding
it a lot easier to make up their
calorie targets using certain foods.
This bottle
of Belgian chocolate milk
is 500ml and has 620 calories.
Lots of chocolate. Chocolate mousse.
Chocolate milk pudding.
Chocolate trifle.
Chocolate.
A huge chocolate milkshake
with ice cream.
And one of those little
Gold chocolate bars.
A marbled Belgian
chocolate cake slice,
which was 305 calories
and quite nice.
Chocolate mousse.
Swiss chocolate Original.
A big chocolate tart.
Belgian chocolate flapjack.
A chocolate muffin.
Mint truffle chocolate bar and
a Turkish delight chocolate bar.
And...more chocolate.
It's Saturday night,
and I need an extra 1,100 calories.
I found this little bad boy.
It's Saturday night,
and I need an extra 1,100 calories.
I found this little bad boy.
A good cake!
Our volunteers found
that eating chocolate
was a very good way of increasing
the number of calories.
The reason for that is
chocolate is very calorie-dense.
That means there's a lot of calories
in a small amount of volume,
and therefore you can
eat the chocolate
and actually have another one
before you feel full.
That's why chocolate is so dangerous.
But the question is, why are some
of us so much better at walking
past an open bar of chocolate
or packet of biscuits than others?
Is staying slim simply a matter
of exerting a little self-control?
As a psychologist I've always been
very interested in eating behaviour,
and specifically the question
of why some people seem to eat more
than they strictly need
to fulfil their energy requirements.
People often assume
that the answer to that
is just willpower or self-control,
but I think there's
more to it than that.
Professor Jane Wardle has been
investigating why some people
persistently eat more
than they really need to.
She's come to the Hopes and Dreams
Nursery in North London
to repeat one
of her recent experiments.
The idea of this study is to
see how responsive people are,
children are in this case,
to food that's put in front of them
at a time when actually
they're fairly full.
The experiment starts after lunch,
with colouring.
I'd quite like to check that
from their point of view
they do feel full.
Empty, half full or full?
Do you think your tummy's full?
CHILD: I had two.
So they choose which of these figures
is how they feel,
and I think pretty well all the ones
I've heard talking
have said they feel very full.
Now they're all being handed a little
plate, or quite a big plate actually,
of party-type food,
and each child's told
they can eat the food,
or they can colour, or they
can do a bit of each as they choose.
Each plate of food contains 340
calories' worth of chocolate, cakes
and biscuits, cut into small pieces.
To put this in perspective,
that's approximately a quarter
of these children's average
daily requirement of calories.
If you look round,
you can see there's already a lot
of difference in what's going on.
You know, that little boy over there,
he seems to have pushed his plate
right over to the other side
of the table.
you know, as though he's
not interested at all in it.
But the boy he's sitting next to
is kind of eating away.
Now if you look at that table down
there, the two children at each end
their way through all the food
on their plates, and if you look at
the two sitting either side there,
interested at all.
They're not just
all copying each other
and doing the same
as the other children on the table.
Jane believes that these
behaviour patterns
are already well-established in
these four- and five-year-olds.
For some people, once they feel that
they're full, their enthusiasm
and interest in doing any more eating
is just switched off,
whereas others, as long as the food
that they're being offered
is attractive and good tasting,
they're happy to carry on eating.
Studies have shown that our
eating behaviours are fixed
from a very young age.
The chances are if you have a
tendency to carry on snacking
after you're full as a toddler,
you'll behave the same way
as an adult.
The problem is that it's
not long before these habits
start to affect your body weight.
By age 11, you usually will
start seeing there are associations
between these kind of traits,
and the children's weight.
The interesting question for us now
is where the variability that we see
in children's eating behaviour
comes from.
Is it something that's learned at
home in the family context,
in children's eating behaviour
comes from.
Is it something that's learned at
home in the family context,
or is it something that is innate,
and perhaps a genetic characteristic?
So we've been doing a very
similar experiment
to the one that you saw here,
but the children in that study,
we've also tested them
to see what variant they have
on a gene called the FTO gene.
types of the FTO gene.
Adults who have one variant
of this gene
weigh on average
more than everybody else.
And what we showed was that
the children who ate more in this
so-called eating in the absence
of hunger task,
tended to have the higher risk
variant of the FTO gene,
and the children who ate very little
had what I think of as being the
protective variant of the gene.
It seems that the size of our
appetite has a genetic basis.
So it looks like
that for some people,
resisting all the foods that are
available in the modern environment
is actually fairly easy.
It's kind of effortless because they
don't even want to eat them,
they're not having to exert
willpower and self-control,
whereas for other people,
their brain responses to foods
that they're exposed to aren't
being switched off effectively
as a consequence of them
already having had enough.
Hello! OK? Come through.
Professor Wardle's findings
could certainly explain why some of
our volunteers started off so slim.
To be honest, I don't really eat
when I'm not hungry.
I mean, if I am hungry,
I can eat and eat and eat,
but as soon as I stop being hungry,
I stop eating.
I'm not the kind of person to
go for extra biscuits
or sugary snacks if I'm not hungry.
I don't normally eat
when I'm not hungry,
I don't eat just
for the sake of it.
At weddings or things when
we've had a huge amount of meal,
and then they bring out the desserts
and they look really pretty,
and I would go for one,
just impulsively,
and I'd have a spoonful or something,
but then I just couldn't
eat any more.
So I'd really want to,
but I wouldn't be able to.
It seems that in everyday life,
they're the kind of people
who just don't have any desire
to eat more than their body needs.
of the experiment,
all of our volunteers are ignoring
their normal appetites.
And now I'm about to tuck into this,
admittedly a meal
meant for two people,
but obviously for the purpose
of this experiment,
I shall be eating it all,
with my flat-mates
very impressed with that.
1,700 calories,
that's more than a fry-up...
that I had this morning.
They have to eat
their calorie targets,
whether they feel like it or not.
They have to eat
their calorie targets,
whether they feel like it or not.
And in some cases,
that means desperate measures.
What's Tom going to eat?
Ooh, the...clotted,
the clotted cream.
What's Tom going to eat?
Ooh, the...clotted,
the clotted cream.
Finished!
Not really...
Almost finished.
Hello, Thomas.
At the week two tests,
there are still big differences in
weight gain between the volunteers.
First week it was 73cm.
Now you're 76.8.
Nearly 4cm in two weeks!
Six centimetres!
Six centimetres in two weeks.
I probably did have
tight trousers then!
Thomas Hampton
and Thomas Patel-Campbell
are now both more than 6% heavier
than they were at the start.
But Martin Wong has put on
only 3.5% in weight,
despite sticking
to his calorie target,
There has to be another explanation.
The key issue are where
the calories end up.
If it doesn't end up as fat tissue,
I mean, those that apparently
have more difficulties
in gaining weight than others,
somehow they have
to spend the calories.
in gaining weight than others,
somehow they have
to spend the calories.
Different groups of scientists
have different theories
to explain how people's bodies
use up excess calories
if they're not storing them as fat.
to explain how people's bodies
use up excess calories
if they're not storing them as fat.
We'll be putting one of these
ideas to the test.
In this study we are interested
in what is really the essence
of being protected
against becoming obese,
and a theory we have is that
the people who can eat a lot
and not putting on any weight
actually increase the basal
metabolic rate,
which is proof that they make heat
out of the calories they consume
rather than putting it on as fat
tissue or exercise, either way.
Our base, or resting, metabolic rate
is a measure of how many calories
our body uses just keeping us alive.
It's the amount of energy our
body needs to keep our heart beating
and our brain whirring.
Our volunteers are having their
resting metabolic rate tested
at regular intervals
throughout the experiment.
At the end of the four weeks,
these measurements may help
to explain why
some people have
stayed skinnier than others.
But even the slimmest members
of our group
shouldn't assume they'll
stay that way for ever.
Dr Nikhil Dhurandhar believes that
there is something out there
that could turn
even a naturally thin person fat.
Dr Nikhil Dhurandhar believes that
there is something out there
that could turn
even a naturally thin person fat.
He believes that obesity
may be catching.
My studies with obesity
began in the late-80s when a
colleague of mine was investigating
My studies with obesity
began in the late-80s when a
colleague of mine was investigating
a viral infection in chickens which
was killing chickens by the thousand.
What was odd about the phenomenon was
that these chickens had a lot of fat.
When Dr Dhurandhar's team tried
infecting another group of chickens
with this SMAM-1 virus,
they too became ill and fat,
but what they didn't know
was whether this chicken
virus had crossed over
into the human population, and
whether it could make us fat too.
Experiments with animals are in one
sense simple, because you can take
an animal, infect it with a
virus and see a cause and effect.
Of course, for ethical reasons,
you can't do this with humans.
You can't take humans,
even if they are willing,
you can't infect them with a virus to
show a cause-and-effect relationship.
So instead, Dr Dhurandhar
took blood samples
from 50 of the overweight patients
that he was treating
at his obesity clinic.
His team analysed their blood,
looking for the presence of
antibodies to the chicken virus
which would show that they
had been naturally infected
at some point in their lives.
Turns out about 20% of them
were infected with the virus,
and as we predicted,
these naturally infected people
were significantly heavier
compared to their
antibody-negative counterparts.
Since then, Dr Dhurandhar's team
have begun studying a human pathogen
which belongs to the same
family of oedemal viruses
as the chicken virus.
In humans these oedemal viruses
cause cold and cough,
or pink-eye - conjunctivitis -
or diarrhoea,
and we have now more than
a thousand patients studied,
and it continues to show
association with obesity
and this infection with this virus.
In one study, Dhurandhar's team
found that obese people were nearly
three times more likely to have the
virus than a non-obese person,
and, even amongst
the non-obese group,
those infected with the virus
were heavier than average.
And when they started studying how
the virus spread through the body,
they found out why.
From our animal studies, we now know
that this virus goes to the lungs
and spreads through the body,
goes to various organs and tissues,
goes to the liver, kidneys,
the brain and fat tissue.
When this virus goes
to this fat tissue,
it replicates,
making more copies of itself,
and in the process, increases
the number of fat cells.
Which may explain why
the fat tissue expands,
and why people get fat when
they are infected with this virus.
Should we be avoiding fat people?
Are they going to make us fat too?
I am often asked this question,
Are they going to make us fat too?
I am often asked this question,
but based on our animal studies,
we believe that people would be
infectious only
for a short period of time,
maybe two or three months
after they are infected.
That's one. But the other thing
is people could be fat
for reasons other
than viral infections,
so it's really pointless
to try to avoid fat people
to prevent infection.
Dr Dhurandhar's research suggests
that even the volunteers
who put on the least weight
in our experiment
shouldn't feel too complacent.
The next cold they catch could come
with some undesirable side-effects.
Look at my tummy.
Look at that, it's just
it's not normal to me at all,
and it's really uncomfortable.
My jeans are too tight,
and I'm sick of it.
I can't wait to get rid of it all.
During the last two weeks
of the experiment,
many of our volunteers are
starting to really notice
the changes taking place
in their body for the first time.
This is insane.
I've had to go up two dress sizes,
and I've actually gone up two
cup sizes on my bra as well.
My trousers are tighter.
My jeans don't fit me and
I've got the muffin-top,
with love handles round the sides.
Everything's a bit flabbier.
I have felt that I've
got a bit more of a gut.
You've got a bit of a belly.
A little bit, yeah.
It's just a kind of, I don't know,
it doesn't usually bounce that much.
I haven't exactly been playing with
it or anything, but it's kind of...
It's just a kind of, I don't know,
it doesn't usually bounce that much.
I haven't exactly been playing with
it or anything, but it's kind of...
Most of us never think about what's
actually going on under our skin
when we start gaining inches.
But not everybody's fat is the same,
and that's one reason why some
of us are bigger than others.
It was in the early-60s
that people for the first time
started to ask the question,
what happens when you gain weight
with respect to our fat cells?
Obviously you have two possibilities.
They can either increase in size,
or they can increase in number,
and the fact is
both of these things happen.
So if we start out with a set of
small fat cells that we see here,
and we start to over-eat,
these fat cells tend to get bigger
and they start to accumulate
more energy, more oil
and eventually they turn
into these huge cells
that you essentially can
see with your naked eye,
the size of a full stop.
It's what happens next that decides
whether you will spend the rest
of your days fighting the flab.
This increase in fat cell size
happens up to a certain point
beyond which these cells
just can't get any bigger,
and it is at this point
that the system decides
that we need more fat cells.
The bad news is once we have
this increased number of fat cells,
they're there to stay.
We'll never lose them again,
and their job description is,
to as effectively as possible,
accumulate as much fat as they can.
So once we have
these fat cells there,
it is almost impossible
to get rid of them,
So once we have
these fat cells there,
it is almost impossible
to get rid of them,
and we will be much more prone
to be overweight at that point.
Research shows that it is much
easier for our body
to make extra fat cells during our
childhood and adolescence,
which means that a chubby
stage when you're growing up
can affect you
for the rest of your life.
However hard you try,
you can never reduce the number
of fat cells in your body.
And the more of them you have,
the more likely you are
to put on weight easily.
Put simply, overweight children
are extremely likely to end up
as overweight adults.
As children,
our volunteers were always slim,
and that's part of the reason
why they find it easy
Second to last day.
Wahoo!
How are you? Not too bad, thanks.
You? Good, thank you.
Even now, after four weeks
of over-feeding,
none of the volunteers have
become clinically overweight,
but that's not to say
that some of them
haven't got significantly fatter.
It's time for the final results.
Were the Vermont
experimenters right?
Will there really be much difference
coped with the extra calories?
I have the final results.
So in second place,
with 9% weight gain,
which is equivalent of 5.5kg,
is Thomas Patel-Campbell.
Yeah!
And in first place, Thomas Hampton,
with 9.5% weight gain,
which is equivalent of 6.5kg.
Respect!
In the beginning, I was all talk,
and now I'm all trousers.
And the findings absolutely confirm
the Vermont study.
Thomas Hampton's 9.5
increase in body weight
is nearly double that
of Jonathan DeCorday-Long
who only put on an extra 5.5%,
but the most intriguing
result is Martin Wong.
His weight gain of 8%, or 4.5kg,
was in the mid-range for the boys,
but his appearance
hasn't changed at all.
Compared to some of the others
doing the study,
it's not that noticeable
that I have a belly,
and I don't know where the fat
has gone. Could be anywhere!
For the last time!
According to the Bodpod, the answer
is that he hasn't put on much fat.
His body fat percentage has only
gone up slightly, by 2.4%.
So if it's not fat, what is it
that accounts for his weight gain?
Martin's an interesting case.
He's gained a lot of weight.
We know it's not a lot of fat,
but what he did increase
is his basal metabolic rate.
Martin's base metabolic rate
has gone up
by an incredible 30%
during the experiment.
The reason why we think Martin's
metabolic rate has increased
is because he's actually
gained a lot of muscle mass,
and muscle needs more energy.
Muscle tissue has a higher metabolic
rate than, for example, fat or bone,
and if you have an increase
in muscle mass,
you will also see a dramatic
increase in basal metabolic rate.
So even though Martin hasn't been
working out or doing any exercise,
he's become more muscly.
Studies have shown that this
tendency to lay down muscle
rather than fat when we over-eat
is genetically determined.
But what about the results
of the other volunteers?
Neither Jonathan DeCorday-Long
nor Victoria Pagner
put on much weight compared
to the two Thomases,
but their base metabolic rate
didn't change significantly either.
One possible explanation is that
they've increased their fidgeting.
The body actually tried to get rid of
energy by moving their hands,
One possible explanation is that
they've increased their fidgeting.
The body actually tried to get rid of
energy by moving their hands,
moving their feet,
maybe moving their head
more than they would have before,
because all of that takes energy
and the body will protect itself from
gaining excessive amount of weight
by burning this unnecessary energy.
And amongst the group,
there are two participants
explanation for why some people
find it hard to put on weight.
Physically eating enough food
was a challenge for many
of the volunteers,
but Ben and Aisha were the only two
who actually failed to reach
their calorie targets.
As much as I tried to get the
calories in, there is no room.
Every mouthful that I
take is a struggle,
I am having to fight
a gag reflex to swallow,
and each mouthful makes me feel
worse and worse and worse,
and I know from the experience
of the first couple of weeks
that if you keep pushing
when you get to that stage,
eventually you throw up anyway.
Ben and Aisha interestingly
could not consume as many calories
as they were set as a target.
Now the reason for this is their
bodies were trying to protect it
from gaining excessive
amounts of weight.
The way the body was doing that
is by increasing their fullness
by natural mechanisms,
natural hormones that
come from the stomach
and actually blocks you
eating more food.
What our study has shown is
that there are big variations
in the way our bodies behave
when faced with excess calories.
It's clear that when it comes
to staying slim,
there's a lot more to it
than diet and exercise.
The lucky ones amongst us
seem to have bodies
that are built
to actively resist weight gain.
But that's not quite
the end of the story.
What about the vexed question
of losing weight?
How will our volunteers face getting
back to their original shapes?
Why some of us find it so hard
to lose weight is a question
that fascinates Dr Leibel's
team at Columbia University.
Over the last few years,
they have been carrying out
an extreme experiment
on a group of obese volunteers.
Their human lab rats
spend up to two years
living under constant observation
on the wards at
the clinical research centre.
First they starved them, so that
they lost 10% of their body weight.
Then, they began feeding them
the precise amount of calories
they needed to maintain this weight.
In our most recent studies,
we've examined the effects
of a 10% reduction in body weight and
maintenance of that lower body weight
on these individuals.
Despite being fed enough calories,
they themselves report
persistent hunger.
Dr Leibel found that the patients'
brains were still responding to food
as if they were starving.
Using modern
brain-imaging techniques,
in the location and degree
of activity of brain centres
in response to weight loss
in these individuals,
and these patterns are consistent
with those one might imagine would
be present in an individual who
was in a state of semi-starvation.
According to Dr Leibel,
that's because their body
regards their obese weight
as the correct weight for them,
and it's fighting to bring them
back to their original larger size.
So the biology of the regulation
of body weight is such
that an otherwise successfully
weight-reduced obese individual
is going to have to live with more
or less constant sensation of hunger
if they intend to be able to maintain
that reduced
body weight indefinitely.
But what's bad news
for the obese patients
is good news for our volunteers.
Their slimmer starting weights are
what their bodies consider normal.
So now the experiment has ended,
they should have little trouble
getting back to their
original weight.
Just thought I'd show you what
happened to my waistline.
Weighed myself on a decent
set of scales the other day,
and lost all the weight,
which is good.
It's been quite a while now
since I finished the study,
and I'm happy to say that
I think I'm completely back
to how I was before.
My clothes all fit,
and I feel a billion times better.
I haven't done anything
to try and lose the weight.
I think I've lost
most of the weight.
I've gone down in all my belts,
and they're all back
to the right button hole.
After two weeks, considering
I put on 5.5kg
and something like six or seven
centimetres around my waist,
that's pretty good.
One month after
the experiment finished,
the volunteers had lost most or all
of their additional body fat.
Their experiences support the
theory that our bodies
have their own idea about what
weight they want us to be.
Individuals have a biology
which determines how tall
or short they will be,
and individuals have a biology
that determines how
skinny or fat they will be,
and wishing it one way or the other
really can't change it very much.
But that's not to say
we should give up
trying to shift any excess pounds.
What may be depressing for many
people who are overweight
to know that actually a large amount
of weight loss is very difficult
to maintain in the long term.
However, we know that small
amounts of weight loss
will make you healthier, and actually
it's much easier to maintain.
As for our volunteers,
taking part in the experiment may
not have changed the way they look,
but it has changed
the way they think.
I mean, I know the calorie
content of everything now.
I mean, it's quite annoying
for some of my friends,
and my girlfriend especially,
you know, "Shouldn't eat that,
that's 800 calories."
"Shouldn't eat that, oh, 1,200."
"That pizza, Meat Feast, forget it!"
I think, certainly this has changed
my attitude to my own body.
I mean...
..I found that actually my
body can be quite resilient,
but only within certain limits.
I'm not sure I'll ever
eat another croissant.
originally fairly slim abdomen,
something like this,
and now look at it.
That is disgusting.
Ten people are about to find out
just how fat they can get.
It's just filthy.
Thanks to Horizon,
they're going to spend four weeks
eating more than
they've ever done before
of all the foods we're always
being told to avoid.
Oh, my God!
This month of gluttony
is all to answer a question
that science has struggled
with for 40 years.
The fight against fat
is being lost all over the world.
Britain's children are
facing an obesity time bomb.
Obesity is now so rife
that it has brought about
an evolutionary change
in the human body shape.
We're all going to become fat.
Low-besity, that's the new word.
The full extent of Britain's
obesity crisis
is revealed in a
new government report.
Inside this London cafe,
we've brought together ten members
of a rapidly disappearing part
of the UK population.
Unlike the 15 million of us
who are dangerously overweight,
these people are all...
slim.
The question they're here
to help us answer
is how they managed to stay that way,
despite most of them
never having dieted in their life.
I've always eaten whatever
I wanted to eat,
and my weight's always been very
stable and I've always been quite slim.
I'm really lucky and my friends hate me.
I'm constantly on a diet.
It's called the "see food" diet.
I see food and I eat it.
I eat a fair amount of food,
but my weight stays quite constant,
so I thought it would be interesting
to participate in this.
So what's their secret?
The field of obesity research
is stuffed full of studies
examining those who are
already overweight.
But recently, an expanding
number of scientists
have decided it's time
to take a closer look
at the skinnier ones amongst us.
I've always been
interested in people
claiming that they can't get fat
even though they eat a lot.
99.9% of studies today on obesity is
really made on already obese people,
and doesn't really give you any
reasons for why people get obese.
We need to figure out some way
to avoid obesity,
and why not try to learn something
from those that apparently
can't get obese.
Swedish scientist Professor
Fredrik Nystrom has come up
with an experiment to investigate
how different people's bodies cope
when they eat a lot more
than they need to.
Over the next four weeks,
our brave volunteers will be eating
double their normal number of
calories and doing no physical exercise.
It's a regime guaranteed to
induce significant weight gain
in even the slimmest person.
At least, that's what you'd assume!
But 40 years ago,
a group of American scientists
carried out a little-known study,
and their incredible findings
suggest otherwise.
Their story begins in the
most unlikely of places.
In 1967, the inmates
of the Vermont State Prison
were approached by
medical researcher Ethan Sims
to take part in a unique experiment.
He wanted to find out about the
hormonal changes in our bodies
when we become seriously overweight,
and in order to study that,
he needed to take a group
of people and make them fat,
very fat.
The study called for each inmate
to gain 25% of their body weight.
In return, they were promised
early release from jail.
Over the course of the year the team
fed the volunteer prisoners as much
as they could physically eat,
and carefully monitored their
bodily changes, but as it went on,
Dr Sims became concerned
by an unexpected finding.
However much they ate,
some of the prisoners
could not reach the target.
Two of the prisoners
got stuck at 21%,
and one of them couldn't put any
more than 18% extra body weight
despite eating as much
as 10,000 calories a day.
The experiment pointed to a
fascinating and unexpected conclusion.
It seemed that for some people,
becoming obese is not just unlikely,
it's practically impossible.
For years Sims' results have
remained the subject of fierce debate.
Could it be true that some people
really can eat as much as they want
without becoming obese?
And if so, how do they do it?
Good evening, everyone,
and welcome to Horizon's
over-feeding experiment.
Before we all get started, we want
to show you how much food you are
expected to eat for a typical week.
So if you help me to remove these...
The food on the table
corresponds to 35,000 calories
which then should give you
5,000 calories a day,
which is what the typical male
in this study is expected to eat.
That's a lot of food.
I think I might run home.
LAUGHTER
It's quite scary, it's quite scary.
It's quite shocking, the volume and the
drinks, the milk shakes and things like that.
It made me feel sick
just looking at it.
It's quite horrifying.
Having seen all
the food here today,
I think it's going to be a lot
harder than I envisaged before.
Obviously it's a bit daunting,
but I reckon it's deceptive.
I reckon if, you know,
you spooned it into days
rather than just all these plates
here, I reckon it would look fine.
I reckon I can take that.
If the Vermont prison
experimenters were right,
there could be
surprising differences
in how the bodies of the volunteers
respond to their new diet.
Some might fail
to put on much weight at all
and, at the other end of the scale,
there's a chance that someone
may have to leave the study
before the four weeks is up.
The upper limit of the increase
in body weight in this experiment
will be 15%.
It's not ethical
to go any further than that.
If anybody increases 15%, they're
going to be taken out of the study.
The average weight of our
volunteers is around 63kg.
An increase in body weight of 15%
would mean nearly ten extra
kilograms, or one and a half stone.
For the women, this could mean going
up two dress sizes in four weeks.
People are quite horrified
that a girl's doing it.
They can understand
why guys might do it,
and sort of get to eat
as much as they want,
but no-one seems to get why
a girl would want to get fat.
During the experiment,
we're going to keep track
of the participants' weight,
and carry out a series
of medical tests on them.
The aim is to uncover some clues
as to how they manage to stay slim
in an increasingly fat world.
Not that fat is
necessarily a bad thing!
At least, that's what
Dr Philipp Scherer believes.
He has devoted his career to
studying this much-maligned substance.
So what we're looking
at here is a rather
large piece of bovine fat, from a cow, obviously,
and if you look at
fat tissue from humans,
that would look exactly the same way.
So this is the tissue
that has a really bad reputation,
but fat is a really
marvellous substance,
and has a lot of really
wonderful qualities to it.
When it comes to fat,
all most of us want to do
is get rid of it
as quickly as possible.
We don't stop to think about
what our fat does for us.
Inside this fat tissue,
we've got billions and billions
of little fat cells,
and each one of these fat cells
has an oil droplet stored,
and if the body is in need of energy,
it can burn this oil
in a chemical reaction.
The energy contained
inside these cells
can keep us going
when food supplies are scarce.
Our fat is our body's
built-in emergency rations.
There is in fact a pretty wide range
within the human population
in terms of how much fat
each one of us carries around.
There are those that are
seriously overweight,
and some of those can actually...
have up to 100 times the amount
of fat that you see in this bowl.
And the more fat we have,
the longer we can keep going
without eating,
as one Scottish PhD
student found out.
the longer we can keep going
without eating,
as one Scottish PhD
student found out.
In 1968, she began conducting
an experiment on a 450lb man
who was desperate
to lose some weight.
He agreed to begin fasting
under her medical supervision,
and stopped eating or drinking
anything but water and vitamins.
Eventually he managed to
lose 275 pounds in weight.
He had lasted an incredible year
and two weeks without food.
But even a slim person can live off
their fat for several weeks.
The average lean individual probably
has about ten times the amount of fat
that you see in this bowl,
and it makes you wonder,
where are we putting it all?
What this means is
the average individual
can easily keep going
for more than a month.
In today's world, of course, we
never need to go without food
for anything like
as long as a month.
In fact, we are unlikely to have
to last more than a few hours.
But that wasn't the case
for most of human history.
According to obesity
geneticist, Dr Eric Ravussin,
our hunter-gatherer ancestors
had to live off
whatever they could find.
Sometimes that wasn't much,
which is when fat
as an efficient storage system
really came into its own.
Populations went through
periods of feast and famine.
During the periods of famine,
maybe two-thirds or three-quarters
of the population would disappear.
But those who were chubbier
or those fatter babies
would survive and then procreate
themselves and pass on these genes.
So according to this theory,
at times of famine,
it was literally a case
of the survival of the fattest.
The cycles of feast and famine that
humankind has been subjected to
was an important natural selective
process in which all the babies
or the people who were
a little bit chubbier
would survive the periods of famine,
and then be able to gain the
weight during the period of feast.
This could explain why large parts
of the population
have a tendency to lay down
fat stores easily.
It's only very recently
in human history
that this has become a problem.
Now the feast is constant,
you have food available every corner,
very cheap, very palatable and this
is really a perfect mixture
to provide the expression
of these genes
and confer obesity and
weight gain to these people.
And I think that this stigmatising
of the obese population is wrong,
because those were the survivors,
those are the people
who would survive
a difficult and tough environment.
But although putting on fat easily
may have been an advantage
in the past,
in today's environment,
the opposite is true.
It's the naturally slim who
live longer, healthier lives.
It's the day before our
volunteers begin their four weeks
of over-feeding, and they've come
to the University of Westminster
for some tests.
Every inch of their slim physiques
will be scrutinised.
OK, a sharp scratch coming up.
Ania Kosicka will be carrying
out the various tests.
And clinical obesity specialist,
Dr Carel le Roux
is overseeing the experiment.
He will be monitoring the
health of the volunteers throughout.
You have not increased much.
It's gone from 48kg to...
Determining how much body fat
they currently have
involves the space-age Bodpod...
BODPOD VOICE:
"Welcome to the Bodpod."
..a shower cap...
Quite how this is going to work,
I don't know.
..and no clothes.
What this measurement does
is it actually looks at
the air that's been displaced
by the body.
HE TAKES DEEP BREATH
And by using the patient's age,
gender, as well as weight,
we can actually calculate
how much of his body is fat
and how much of his body is muscle.
OK, so your percentage body
fat is 7.6.
Which puts you in the
ultra-lean category, OK?
According to the Bodpod,
hospital administrator Leo Dennett
has the lowest percentage
body fat of all the participants.
And medical students
Catherine Hannon
and Victoria Pagner have the most.
In both their cases, fat makes up
at least 20% of their body.
What we saw today in the volunteers
is that the men had half the amount
of fat than the women,
and that is what we would expect
in the general population.
For the purposes of the experiment,
each volunteer's normal daily
calorie requirement
For the purposes of the experiment,
each volunteer's normal daily
calorie requirement
has been calculated
taking into account
their physiological statistics.
These individual figures
have then been doubled
to work out how much each
of them will be eating
over the next four weeks.
They're also banned
from doing any physical exercise
that could skew the results.
They're also going
to carry pedometers
so that we can keep track of
the amount of steps that they make,
and we ask them not to walk more
than 5,000 steps a day,
so that we can keep track of
the amount of steps that they make,
and we ask them not to walk more
than 5,000 steps a day,
which roughly corresponds
to something like two miles.
For many of the volunteers,
the tension is building
as they face up to what lies ahead.
I'm actually very nervous now,
because tomorrow morning
I've got to eat a huge breakfast,
a massive, massive fry-up and,
and there's not going to be enough
time in the day, I think,
to fit in all this eating!
I was definitely looking
at fat people on the tube...
with a bit of apprehension, but I'm
pretty sure that I doubt that
I'll go anything above like...
..what, 73, something like that.
I think I've got it under control.
Many of us are concerned
by the slightest change
when we step on the bathroom scales.
But New Yorker Dr Rudy Leibel
is surprised that our weight
doesn't fluctuate a lot more.
One of the remarkable aspects
of human body weight
actually is how stable it is
over relatively long periods of time.
So for example the average adult
between the ages of 20
and 50 or 60 years of age
may gain 20 or 30 pounds.
But when you do the maths on this,
it's as little as seven extra
calories or ten extra calories
of food a day, which works
out to a potato chip or a French fry.
It seems that most of us
stay the same weight
for the whole of our adult lives,
apart from a slow
middle-aged spread.
But if all that was
affecting it was diet,
we'd have to be controlling the
number of calories we eat
to within seven calories a day.
We don't think that a human could
consciously control their body weight
to that level of precision.
Instead Dr Leibel believes
that we all have
a biologically-determined
natural weight
which varies from person to person,
and our bodies do their best
to maintain us at that weight,
be it fat or thin.
That doesn't mean that you cannot, by
over-eating consciously or responding
to delicious meals that
are in the environment,
or for example undertaking a
conscious effort to exercise a lot,
can't move this around a little bit,
but the body will constantly tend to
try to bring you back to whatever
your normal body weight is.
So if we're all stuck
with a natural weight,
what determines it,
and how early in life is it set?
According to Dr David Allison,
even events that take place
before we are born
whilst we are still in the womb
can affect the size we are destined
to become as adults.
There's now clear and emerging lines
of evidence indicating that several
factors can have long-term effects
on obesity and degree of body fatness
throughout life, even when those
effects occur in the womb.
We know that, for example,
older sheeps have fattier lambs,
and we know that older women,
women who give birth at a later age,
tend to have children that are more
likely to be overweight or obese.
And it seems that the mother's
weight and nutrition
during pregnancy are also crucial.
We also know that a mother that
is overfed or obese or diabetic
at certain portions of the pregnancy
will produce offspring
that have a greater probability of
themselves being overweight or obese.
There are a host of other
possible influences
including environmental factors,
even pollution.
Scientists are only just beginning
to uncover the many things
that may predetermine our weight.
But the message is clear.
It seems our size is much less under
our control than we might believe.
Day one.
I've eaten today
two chocolate croissants,
a lot of Crunchy Nut
and milk, pork pie,
a whole pizza with mayonnaise,
bottle of smoothie,
tub of ice cream, Ben and Jerry's
Phish Food,
couple of burgers
and some vegetables, um...
but I did cheat because
I kind of vomited once.
Um...it's pretty difficult.
Felt pretty ill most of the day.
Two pork pies.
Jaffa Cakes.
A large Quarter Pounder
Cheese meal
with strawberry milk shake
and a McFlurry.
Then another pork pie.
A melt-in-the-middle chocolate
pudding with cream...ha-ha-ha!
Chicago Town deep dish pizza
which is "made to share",
which is probably why
it's 1,240 calories.
Pizza with lots of mayonnaise.
Half a cheesecake
and a litre of Coke.
A sausage roll has 90% of the
calories of a Mars Bar.
A whole tub of Ben and Jerry's
with golden syrup.
McDonalds again for breakfast.
Pork pie. Yeah. Another pork pie.
Pate and asparagus,
in a sort of...melange.
Chocolate pudding with cream,
washed down with
a litre and a half of Coke.
To be honest I've hardly
stopped eating all day.
And I've had some of the kind of
most calorific food known to man,
and I've been full all day,
and I'm still nowhere near my target.
I think I went into this thinking
it would be easier than it is,
and I felt sick,
I feel...I feel disgusting.
This lack of exercise is killing me,
I mean, not being able to walk
is driving me mad.
I have a kind of a constant
sickly sweetness taste in my mouth.
Try and get it off.
I did discover that McDonalds doesn't
fill you up at all,
it has loads of calories in,
which is good.
And beer has a lot of calories in.
I thought Guinness would be a lot,
but Guinness is actually less than
most lagers, which is surprising.
OK, so this is the end of day six.
Tomorrow is our first weigh-in.
I'm really interested to see
how much weight
I'm going to have put on.
At the week one weigh-ins,
there's a surprise in store
for one of the participants.
OK, hello, Thomas!
Hello!
Thomas? Yes.
Your weight last week was 68.3kg.
Thomas? Yes.
Your weight last week was 68.3kg.
This week, it's 71.1kg.
So there's about 3kg increase,
and your percentage body fat
was 14% last week,
and this week it's 16.2.
I guess I'm putting the weight on
where it matters.
I don't know. I guess,
I guess I kind of expected that
to happen, but not quite as fast.
I'm a bit intrigued about
what it's going to be like
next week, third week, fourth week,
because I can expect
it to get worse...
So...trousers, that's a worry.
I'm a big man for tight trousers.
Must do some shopping.
2.8kg is equivalent to 4.1% of
Thomas's original body weight.
It's the highest percentage increase
out of the group.
The moment of truth.
In second place is Leo
Dennett on 3.2%.
The percentage body fat
today is 10.4. Oh, right.
So we have about 3.2% increase. OK.
It's quite a lot in one week.
Yeah, I'm not surprised, really,
to be honest.
According to the Bodpod,
he's gained so much new fat he's
moved out of the ultra-lean category
whereas both Aisha Rashid
and Martin Wong
have only gained a paltry
1.6% body weight.
It's almost like a mini-competition.
I'm aiming to either have to get
withdrawn from this
by putting on so much weight,
or turn up on the last day going,
"Yeah, I've been eating loads
and I'm still hungry."
BODPOD: "Welcome to the Bodpod,
please open the door." Stylish!
So, just one week in and already
there are striking differences
in weight gain
amongst the volunteers.
Look at the results...
Doubling your normal
number of calories
does not affect everyone
in the same way.
So I've put on one kilo,
but 5% more fat. Yes.
But the biggest surprise
for many of the volunteers
is how hard it has been
to eat double their
normal number of calories.
It does get really sickening,
like waking up at...
5am to eat chocolate peanuts!
You start off feeling terrible
and so you can't eat,
you can't eat so you get behind,
and it makes you feel terrible,
and you think that to feel un-terrible
you should force yourself to eat.
That makes you
feel more terrible,
and you end up missing a meal,
and end up losing more calories
than you made up by forcing
the snacks down yourself,
and you just feel more terrible,
and before you know what's happened,
it's 7pm and you're like...right!
Eff today, I'm starting
again tomorrow.
As their food diaries reveal,
our volunteers are all finding
it a lot easier to make up their
calorie targets using certain foods.
This bottle
of Belgian chocolate milk
is 500ml and has 620 calories.
Lots of chocolate. Chocolate mousse.
Chocolate milk pudding.
Chocolate trifle.
Chocolate.
A huge chocolate milkshake
with ice cream.
And one of those little
Gold chocolate bars.
A marbled Belgian
chocolate cake slice,
which was 305 calories
and quite nice.
Chocolate mousse.
Swiss chocolate Original.
A big chocolate tart.
Belgian chocolate flapjack.
A chocolate muffin.
Mint truffle chocolate bar and
a Turkish delight chocolate bar.
And...more chocolate.
It's Saturday night,
and I need an extra 1,100 calories.
I found this little bad boy.
It's Saturday night,
and I need an extra 1,100 calories.
I found this little bad boy.
A good cake!
Our volunteers found
that eating chocolate
was a very good way of increasing
the number of calories.
The reason for that is
chocolate is very calorie-dense.
That means there's a lot of calories
in a small amount of volume,
and therefore you can
eat the chocolate
and actually have another one
before you feel full.
That's why chocolate is so dangerous.
But the question is, why are some
of us so much better at walking
past an open bar of chocolate
or packet of biscuits than others?
Is staying slim simply a matter
of exerting a little self-control?
As a psychologist I've always been
very interested in eating behaviour,
and specifically the question
of why some people seem to eat more
than they strictly need
to fulfil their energy requirements.
People often assume
that the answer to that
is just willpower or self-control,
but I think there's
more to it than that.
Professor Jane Wardle has been
investigating why some people
persistently eat more
than they really need to.
She's come to the Hopes and Dreams
Nursery in North London
to repeat one
of her recent experiments.
The idea of this study is to
see how responsive people are,
children are in this case,
to food that's put in front of them
at a time when actually
they're fairly full.
The experiment starts after lunch,
with colouring.
I'd quite like to check that
from their point of view
they do feel full.
Empty, half full or full?
Do you think your tummy's full?
CHILD: I had two.
So they choose which of these figures
is how they feel,
and I think pretty well all the ones
I've heard talking
have said they feel very full.
Now they're all being handed a little
plate, or quite a big plate actually,
of party-type food,
and each child's told
they can eat the food,
or they can colour, or they
can do a bit of each as they choose.
Each plate of food contains 340
calories' worth of chocolate, cakes
and biscuits, cut into small pieces.
To put this in perspective,
that's approximately a quarter
of these children's average
daily requirement of calories.
If you look round,
you can see there's already a lot
of difference in what's going on.
You know, that little boy over there,
he seems to have pushed his plate
right over to the other side
of the table.
you know, as though he's
not interested at all in it.
But the boy he's sitting next to
is kind of eating away.
Now if you look at that table down
there, the two children at each end
their way through all the food
on their plates, and if you look at
the two sitting either side there,
interested at all.
They're not just
all copying each other
and doing the same
as the other children on the table.
Jane believes that these
behaviour patterns
are already well-established in
these four- and five-year-olds.
For some people, once they feel that
they're full, their enthusiasm
and interest in doing any more eating
is just switched off,
whereas others, as long as the food
that they're being offered
is attractive and good tasting,
they're happy to carry on eating.
Studies have shown that our
eating behaviours are fixed
from a very young age.
The chances are if you have a
tendency to carry on snacking
after you're full as a toddler,
you'll behave the same way
as an adult.
The problem is that it's
not long before these habits
start to affect your body weight.
By age 11, you usually will
start seeing there are associations
between these kind of traits,
and the children's weight.
The interesting question for us now
is where the variability that we see
in children's eating behaviour
comes from.
Is it something that's learned at
home in the family context,
in children's eating behaviour
comes from.
Is it something that's learned at
home in the family context,
or is it something that is innate,
and perhaps a genetic characteristic?
So we've been doing a very
similar experiment
to the one that you saw here,
but the children in that study,
we've also tested them
to see what variant they have
on a gene called the FTO gene.
types of the FTO gene.
Adults who have one variant
of this gene
weigh on average
more than everybody else.
And what we showed was that
the children who ate more in this
so-called eating in the absence
of hunger task,
tended to have the higher risk
variant of the FTO gene,
and the children who ate very little
had what I think of as being the
protective variant of the gene.
It seems that the size of our
appetite has a genetic basis.
So it looks like
that for some people,
resisting all the foods that are
available in the modern environment
is actually fairly easy.
It's kind of effortless because they
don't even want to eat them,
they're not having to exert
willpower and self-control,
whereas for other people,
their brain responses to foods
that they're exposed to aren't
being switched off effectively
as a consequence of them
already having had enough.
Hello! OK? Come through.
Professor Wardle's findings
could certainly explain why some of
our volunteers started off so slim.
To be honest, I don't really eat
when I'm not hungry.
I mean, if I am hungry,
I can eat and eat and eat,
but as soon as I stop being hungry,
I stop eating.
I'm not the kind of person to
go for extra biscuits
or sugary snacks if I'm not hungry.
I don't normally eat
when I'm not hungry,
I don't eat just
for the sake of it.
At weddings or things when
we've had a huge amount of meal,
and then they bring out the desserts
and they look really pretty,
and I would go for one,
just impulsively,
and I'd have a spoonful or something,
but then I just couldn't
eat any more.
So I'd really want to,
but I wouldn't be able to.
It seems that in everyday life,
they're the kind of people
who just don't have any desire
to eat more than their body needs.
of the experiment,
all of our volunteers are ignoring
their normal appetites.
And now I'm about to tuck into this,
admittedly a meal
meant for two people,
but obviously for the purpose
of this experiment,
I shall be eating it all,
with my flat-mates
very impressed with that.
1,700 calories,
that's more than a fry-up...
that I had this morning.
They have to eat
their calorie targets,
whether they feel like it or not.
They have to eat
their calorie targets,
whether they feel like it or not.
And in some cases,
that means desperate measures.
What's Tom going to eat?
Ooh, the...clotted,
the clotted cream.
What's Tom going to eat?
Ooh, the...clotted,
the clotted cream.
Finished!
Not really...
Almost finished.
Hello, Thomas.
At the week two tests,
there are still big differences in
weight gain between the volunteers.
First week it was 73cm.
Now you're 76.8.
Nearly 4cm in two weeks!
Six centimetres!
Six centimetres in two weeks.
I probably did have
tight trousers then!
Thomas Hampton
and Thomas Patel-Campbell
are now both more than 6% heavier
than they were at the start.
But Martin Wong has put on
only 3.5% in weight,
despite sticking
to his calorie target,
There has to be another explanation.
The key issue are where
the calories end up.
If it doesn't end up as fat tissue,
I mean, those that apparently
have more difficulties
in gaining weight than others,
somehow they have
to spend the calories.
in gaining weight than others,
somehow they have
to spend the calories.
Different groups of scientists
have different theories
to explain how people's bodies
use up excess calories
if they're not storing them as fat.
to explain how people's bodies
use up excess calories
if they're not storing them as fat.
We'll be putting one of these
ideas to the test.
In this study we are interested
in what is really the essence
of being protected
against becoming obese,
and a theory we have is that
the people who can eat a lot
and not putting on any weight
actually increase the basal
metabolic rate,
which is proof that they make heat
out of the calories they consume
rather than putting it on as fat
tissue or exercise, either way.
Our base, or resting, metabolic rate
is a measure of how many calories
our body uses just keeping us alive.
It's the amount of energy our
body needs to keep our heart beating
and our brain whirring.
Our volunteers are having their
resting metabolic rate tested
at regular intervals
throughout the experiment.
At the end of the four weeks,
these measurements may help
to explain why
some people have
stayed skinnier than others.
But even the slimmest members
of our group
shouldn't assume they'll
stay that way for ever.
Dr Nikhil Dhurandhar believes that
there is something out there
that could turn
even a naturally thin person fat.
Dr Nikhil Dhurandhar believes that
there is something out there
that could turn
even a naturally thin person fat.
He believes that obesity
may be catching.
My studies with obesity
began in the late-80s when a
colleague of mine was investigating
My studies with obesity
began in the late-80s when a
colleague of mine was investigating
a viral infection in chickens which
was killing chickens by the thousand.
What was odd about the phenomenon was
that these chickens had a lot of fat.
When Dr Dhurandhar's team tried
infecting another group of chickens
with this SMAM-1 virus,
they too became ill and fat,
but what they didn't know
was whether this chicken
virus had crossed over
into the human population, and
whether it could make us fat too.
Experiments with animals are in one
sense simple, because you can take
an animal, infect it with a
virus and see a cause and effect.
Of course, for ethical reasons,
you can't do this with humans.
You can't take humans,
even if they are willing,
you can't infect them with a virus to
show a cause-and-effect relationship.
So instead, Dr Dhurandhar
took blood samples
from 50 of the overweight patients
that he was treating
at his obesity clinic.
His team analysed their blood,
looking for the presence of
antibodies to the chicken virus
which would show that they
had been naturally infected
at some point in their lives.
Turns out about 20% of them
were infected with the virus,
and as we predicted,
these naturally infected people
were significantly heavier
compared to their
antibody-negative counterparts.
Since then, Dr Dhurandhar's team
have begun studying a human pathogen
which belongs to the same
family of oedemal viruses
as the chicken virus.
In humans these oedemal viruses
cause cold and cough,
or pink-eye - conjunctivitis -
or diarrhoea,
and we have now more than
a thousand patients studied,
and it continues to show
association with obesity
and this infection with this virus.
In one study, Dhurandhar's team
found that obese people were nearly
three times more likely to have the
virus than a non-obese person,
and, even amongst
the non-obese group,
those infected with the virus
were heavier than average.
And when they started studying how
the virus spread through the body,
they found out why.
From our animal studies, we now know
that this virus goes to the lungs
and spreads through the body,
goes to various organs and tissues,
goes to the liver, kidneys,
the brain and fat tissue.
When this virus goes
to this fat tissue,
it replicates,
making more copies of itself,
and in the process, increases
the number of fat cells.
Which may explain why
the fat tissue expands,
and why people get fat when
they are infected with this virus.
Should we be avoiding fat people?
Are they going to make us fat too?
I am often asked this question,
Are they going to make us fat too?
I am often asked this question,
but based on our animal studies,
we believe that people would be
infectious only
for a short period of time,
maybe two or three months
after they are infected.
That's one. But the other thing
is people could be fat
for reasons other
than viral infections,
so it's really pointless
to try to avoid fat people
to prevent infection.
Dr Dhurandhar's research suggests
that even the volunteers
who put on the least weight
in our experiment
shouldn't feel too complacent.
The next cold they catch could come
with some undesirable side-effects.
Look at my tummy.
Look at that, it's just
it's not normal to me at all,
and it's really uncomfortable.
My jeans are too tight,
and I'm sick of it.
I can't wait to get rid of it all.
During the last two weeks
of the experiment,
many of our volunteers are
starting to really notice
the changes taking place
in their body for the first time.
This is insane.
I've had to go up two dress sizes,
and I've actually gone up two
cup sizes on my bra as well.
My trousers are tighter.
My jeans don't fit me and
I've got the muffin-top,
with love handles round the sides.
Everything's a bit flabbier.
I have felt that I've
got a bit more of a gut.
You've got a bit of a belly.
A little bit, yeah.
It's just a kind of, I don't know,
it doesn't usually bounce that much.
I haven't exactly been playing with
it or anything, but it's kind of...
It's just a kind of, I don't know,
it doesn't usually bounce that much.
I haven't exactly been playing with
it or anything, but it's kind of...
Most of us never think about what's
actually going on under our skin
when we start gaining inches.
But not everybody's fat is the same,
and that's one reason why some
of us are bigger than others.
It was in the early-60s
that people for the first time
started to ask the question,
what happens when you gain weight
with respect to our fat cells?
Obviously you have two possibilities.
They can either increase in size,
or they can increase in number,
and the fact is
both of these things happen.
So if we start out with a set of
small fat cells that we see here,
and we start to over-eat,
these fat cells tend to get bigger
and they start to accumulate
more energy, more oil
and eventually they turn
into these huge cells
that you essentially can
see with your naked eye,
the size of a full stop.
It's what happens next that decides
whether you will spend the rest
of your days fighting the flab.
This increase in fat cell size
happens up to a certain point
beyond which these cells
just can't get any bigger,
and it is at this point
that the system decides
that we need more fat cells.
The bad news is once we have
this increased number of fat cells,
they're there to stay.
We'll never lose them again,
and their job description is,
to as effectively as possible,
accumulate as much fat as they can.
So once we have
these fat cells there,
it is almost impossible
to get rid of them,
So once we have
these fat cells there,
it is almost impossible
to get rid of them,
and we will be much more prone
to be overweight at that point.
Research shows that it is much
easier for our body
to make extra fat cells during our
childhood and adolescence,
which means that a chubby
stage when you're growing up
can affect you
for the rest of your life.
However hard you try,
you can never reduce the number
of fat cells in your body.
And the more of them you have,
the more likely you are
to put on weight easily.
Put simply, overweight children
are extremely likely to end up
as overweight adults.
As children,
our volunteers were always slim,
and that's part of the reason
why they find it easy
Second to last day.
Wahoo!
How are you? Not too bad, thanks.
You? Good, thank you.
Even now, after four weeks
of over-feeding,
none of the volunteers have
become clinically overweight,
but that's not to say
that some of them
haven't got significantly fatter.
It's time for the final results.
Were the Vermont
experimenters right?
Will there really be much difference
coped with the extra calories?
I have the final results.
So in second place,
with 9% weight gain,
which is equivalent of 5.5kg,
is Thomas Patel-Campbell.
Yeah!
And in first place, Thomas Hampton,
with 9.5% weight gain,
which is equivalent of 6.5kg.
Respect!
In the beginning, I was all talk,
and now I'm all trousers.
And the findings absolutely confirm
the Vermont study.
Thomas Hampton's 9.5
increase in body weight
is nearly double that
of Jonathan DeCorday-Long
who only put on an extra 5.5%,
but the most intriguing
result is Martin Wong.
His weight gain of 8%, or 4.5kg,
was in the mid-range for the boys,
but his appearance
hasn't changed at all.
Compared to some of the others
doing the study,
it's not that noticeable
that I have a belly,
and I don't know where the fat
has gone. Could be anywhere!
For the last time!
According to the Bodpod, the answer
is that he hasn't put on much fat.
His body fat percentage has only
gone up slightly, by 2.4%.
So if it's not fat, what is it
that accounts for his weight gain?
Martin's an interesting case.
He's gained a lot of weight.
We know it's not a lot of fat,
but what he did increase
is his basal metabolic rate.
Martin's base metabolic rate
has gone up
by an incredible 30%
during the experiment.
The reason why we think Martin's
metabolic rate has increased
is because he's actually
gained a lot of muscle mass,
and muscle needs more energy.
Muscle tissue has a higher metabolic
rate than, for example, fat or bone,
and if you have an increase
in muscle mass,
you will also see a dramatic
increase in basal metabolic rate.
So even though Martin hasn't been
working out or doing any exercise,
he's become more muscly.
Studies have shown that this
tendency to lay down muscle
rather than fat when we over-eat
is genetically determined.
But what about the results
of the other volunteers?
Neither Jonathan DeCorday-Long
nor Victoria Pagner
put on much weight compared
to the two Thomases,
but their base metabolic rate
didn't change significantly either.
One possible explanation is that
they've increased their fidgeting.
The body actually tried to get rid of
energy by moving their hands,
One possible explanation is that
they've increased their fidgeting.
The body actually tried to get rid of
energy by moving their hands,
moving their feet,
maybe moving their head
more than they would have before,
because all of that takes energy
and the body will protect itself from
gaining excessive amount of weight
by burning this unnecessary energy.
And amongst the group,
there are two participants
explanation for why some people
find it hard to put on weight.
Physically eating enough food
was a challenge for many
of the volunteers,
but Ben and Aisha were the only two
who actually failed to reach
their calorie targets.
As much as I tried to get the
calories in, there is no room.
Every mouthful that I
take is a struggle,
I am having to fight
a gag reflex to swallow,
and each mouthful makes me feel
worse and worse and worse,
and I know from the experience
of the first couple of weeks
that if you keep pushing
when you get to that stage,
eventually you throw up anyway.
Ben and Aisha interestingly
could not consume as many calories
as they were set as a target.
Now the reason for this is their
bodies were trying to protect it
from gaining excessive
amounts of weight.
The way the body was doing that
is by increasing their fullness
by natural mechanisms,
natural hormones that
come from the stomach
and actually blocks you
eating more food.
What our study has shown is
that there are big variations
in the way our bodies behave
when faced with excess calories.
It's clear that when it comes
to staying slim,
there's a lot more to it
than diet and exercise.
The lucky ones amongst us
seem to have bodies
that are built
to actively resist weight gain.
But that's not quite
the end of the story.
What about the vexed question
of losing weight?
How will our volunteers face getting
back to their original shapes?
Why some of us find it so hard
to lose weight is a question
that fascinates Dr Leibel's
team at Columbia University.
Over the last few years,
they have been carrying out
an extreme experiment
on a group of obese volunteers.
Their human lab rats
spend up to two years
living under constant observation
on the wards at
the clinical research centre.
First they starved them, so that
they lost 10% of their body weight.
Then, they began feeding them
the precise amount of calories
they needed to maintain this weight.
In our most recent studies,
we've examined the effects
of a 10% reduction in body weight and
maintenance of that lower body weight
on these individuals.
Despite being fed enough calories,
they themselves report
persistent hunger.
Dr Leibel found that the patients'
brains were still responding to food
as if they were starving.
Using modern
brain-imaging techniques,
in the location and degree
of activity of brain centres
in response to weight loss
in these individuals,
and these patterns are consistent
with those one might imagine would
be present in an individual who
was in a state of semi-starvation.
According to Dr Leibel,
that's because their body
regards their obese weight
as the correct weight for them,
and it's fighting to bring them
back to their original larger size.
So the biology of the regulation
of body weight is such
that an otherwise successfully
weight-reduced obese individual
is going to have to live with more
or less constant sensation of hunger
if they intend to be able to maintain
that reduced
body weight indefinitely.
But what's bad news
for the obese patients
is good news for our volunteers.
Their slimmer starting weights are
what their bodies consider normal.
So now the experiment has ended,
they should have little trouble
getting back to their
original weight.
Just thought I'd show you what
happened to my waistline.
Weighed myself on a decent
set of scales the other day,
and lost all the weight,
which is good.
It's been quite a while now
since I finished the study,
and I'm happy to say that
I think I'm completely back
to how I was before.
My clothes all fit,
and I feel a billion times better.
I haven't done anything
to try and lose the weight.
I think I've lost
most of the weight.
I've gone down in all my belts,
and they're all back
to the right button hole.
After two weeks, considering
I put on 5.5kg
and something like six or seven
centimetres around my waist,
that's pretty good.
One month after
the experiment finished,
the volunteers had lost most or all
of their additional body fat.
Their experiences support the
theory that our bodies
have their own idea about what
weight they want us to be.
Individuals have a biology
which determines how tall
or short they will be,
and individuals have a biology
that determines how
skinny or fat they will be,
and wishing it one way or the other
really can't change it very much.
But that's not to say
we should give up
trying to shift any excess pounds.
What may be depressing for many
people who are overweight
to know that actually a large amount
of weight loss is very difficult
to maintain in the long term.
However, we know that small
amounts of weight loss
will make you healthier, and actually
it's much easier to maintain.
As for our volunteers,
taking part in the experiment may
not have changed the way they look,
but it has changed
the way they think.
I mean, I know the calorie
content of everything now.
I mean, it's quite annoying
for some of my friends,
and my girlfriend especially,
you know, "Shouldn't eat that,
that's 800 calories."
"Shouldn't eat that, oh, 1,200."
"That pizza, Meat Feast, forget it!"
I think, certainly this has changed
my attitude to my own body.
I mean...
..I found that actually my
body can be quite resilient,
but only within certain limits.
I'm not sure I'll ever
eat another croissant.