Why Are We Getting So Fat? Horizon

Britain is in the grip of an obesity epidemic.

We can't seem to stop eating and we are getting fatter.

It's one of the greatest public health challenges

of the 21st century

and rarely out of the papers.

"Aporkerlypse Now."

"Obesity as big a threat to the UK as terrorism."

Obesity is all over the news and it garners really shocking headlines.

In recent years, attitudes are becoming more and more judgmental.

There's lots of things that I can't stand

but one of them in particular is fat children.

Do you know who is responsible for you being fat? You. That's it.

When I sit there and I look at somebody that's overweight,

I find that really repulsive and disgusting.

And the verdict seems to be that the obese people are to blame.

They are slothful, they are lazy, they are bad.

In my view, nothing could be further from the truth.

My name is Giles Yeo. I'm a geneticist.

I study genes that are linked to obesity.

I spend most of my time pipetting liquids from one thing to another.

But these test tubes can't tell the full story.

What I want to do is to actually know the person behind these genes.

I want to meet the people behind some of the more alarming headlines.

A lot of fat people, we put on a good facade but inside we're crying.

I want to hear from them why they think they can't stop eating.

That was a general lunch for me.

That was me at the age of 15 there,

not long before I made the decision to lose weight.

I want to dispel some of the myths about obesity...

You're not lazy. It's not because you lack willpower.

You guys are fighting your biology.

..and see what solutions science can offer.

So what we're hoping the faecal transplant will do is help people to

feel more full and therefore will influence weight loss.

Fast forward ten years, obesity won't be a problem.

They'll have the injections. They'll be painless.

No side effects

and actually really inexpensive and freely available.

What's it actually like to live with obesity?

I'm bringing together a group of obese people to hear their views.

With obesity, I think people do treat you differently.

They ignore you. They don't see you as a real person.

Some people have let doors just slam in my face,

looked me up and down in disgust.

You can see their mouths dropping open

because they are just thinking, "Who is that?!"

People certainly think that because you are fat you're not intelligent.

It's a very frustrating thing when people judge you for how you look.

I just think we need to get to a place

where we're just kind to people.

I'm taking a break from my laboratory work

and getting ready for a road trip.

Obesity is perceived as really quite a simple problem,

like eat less, move more.

And that is fine. Simple physics.

The problem, however, is that WHY people eat more is quite complex.

On this trip, I'm going to meet some of the people

behind the newspaper headlines.

I hope my knowledge of obesity genetics can help them and, in turn,

I hope THEY can help me understand the human side to obesity.

I think it would really give me some fresh perspective

and fresh impetus into the type of work that I do.

'As well as the film crew joining me on the road trip,

'I'll be recording some video diaries.

'I think my own lifestyle choices could also offer some

'insights into our relationship with food.'

This is largely a bag of vegetables.

Oh, there are a couple of naughty pizzas back there...

...which we shan't talk about.

For the first stop on this trip, it's time for a few home truths.

I'm going to find out what my body mass index or BMI is.

This is one way to discover if you are a healthy weight,

overweight, or obese.

Actually, do you know what, all this is adding weight, adding BMI.

I'm going to take my clothes off.

Well, not ALL my clothes.

'BMI is a calculation of body size based on your weight

'in relation to your height.'

-MACHINE:

-Stand still and keep your head upright.

People with a BMI over 25...

Please collect your ticket.

...are classified overweight.

HE LAUGHS

My BMI is 27.1.

That means I'm overweight.

The problem with BMI is it doesn't actually tell you how much fat

and how much muscle you have,

so maybe underneath this shirt is a rippling bod of a Greek God?

Or I'm carrying too much fat.

'For another 20p, I can find out.'

Firmly grip the handles at the sides, as shown in the figure.

'By measuring how easily an electrical current travels

'through my body and comparing it to my sex...'

I am a male

'..and age...'

A youthful 42.

'..it calculates my percentage body fat.'

For men, it's recommended that this figure should be under 25.

Please collect your ticket.

'And mine is...'

28%. That's awful!

That's more than a quarter of me that's fat!

Oh, God!

I didn't know... I really genuinely...

Guys, I genuinely did not know it was that bad.

'This fat percentage is not great.

'But what surprised me most

'is how unrealistic I have been about my weight.'

I don't think I look tremendously overweight.

I think I look like the vast majority of the people

wandering around outside.

Is it because our perception of what is overweight and what is not

overweight completely changed over the past few years?

Whether we THINK we look fat or not,

the current statistics make for uncomfortable headlines.

Today, over 60% of Britons are overweight.

Of these, around 40% have a BMI of over 30,

which means they are classified as obese.

And being obese can lead to heart disease, stroke and cancer,

and reduce life expectancy by ten years.

Health-wise, it's just not good at all.

I've got severe diverticular disease.

My knees are giving me awful trouble because of my weight itself.

I was classed as type 2 diabetic.

I've had high blood pressure, high cholesterol.

Getting to an age where it's going to take its toll.

Today I'm heading west up the M4 towards Wales.

I've scoured newspapers from the last few years

to find stories featuring obesity, and track down some of the people

who have generated shocking headlines.

I think there is a lot more going on in the lives of these people

that is not captured in the headlines.

I'm here driving through the fog to meet Les Price.

Les is clinically obese and, because of his size,

he made the headlines a few years back.

This is the story I'm interested in.

"37st man was told to buy two seats on a jet

"and got one in row 17 and one in row 19."

I want to find out what that experience must have been like

for Les and also what else he has to say about being the size he is.

It makes you feel stupid because of all the rigmarole,

cos everyone's like, "What are they talking to him for?

"What's going on there?" It was turning heads.

It was like my life was put out there for everyone to see,

whether I want it or not.

Les has struggled with his size all his life.

As an obese child, you are bullied, you are picked on.

Nobody wants to pick you to play any of their games.

I would go to the shop. I'd buy myself a fun-sized bag of whatever.

I'd go home and just lock myself in the bedroom and hide.

I didn't have to see nobody else.

I could cry if I wanted and just have a tear to myself.

Using food as a comfort is not uncommon and, for Les,

this habit escalated when life dealt him a harsh blow.

My wife died.

We hadn't been married a year and it knocked me.

I just didn't want to do nothing. I couldn't be bothered to cook.

My daughter then, she come home from school,

"Oh, can we have a takeaway?"

"Go on, we'll have a takeaway."

It was, like, for months that's all we had, was takeaway,

but then that took me back then to when I was younger

and the taste of something was the comfort.

You know, you can wrap yourself in that blanket

because it doesn't matter what anyone done out there,

you're in that little comfort zone because a lot of fat people,

we put on a good facade but inside we're crying.

-Hmm.

-You know.

For Les, the way obese people are portrayed in the media

only makes things worse.

Fat people in the media, it just goes fat, that's it.

They've got no idea what has happened in my life.

Do I need you to come along and put a stamp on it and say, "You're fat."

I know I'm fat, you know. I try my best to lose it.

But it is hard work with life all-round.

I am not physically able to go and exercise at the moment.

I've got shoulder problems. I got arthritis in two knees.

I need the help around me

to put everything together to get other things going.

-It sounds very frustrating, Les.

-Life is very frustrating.

People just see the fat guy and just think,

"You've got to stop doing this."

I was genuinely moved by meeting Les today.

Clearly a number of different events have happened

throughout his life to lead him to being the size he is.

You could say that he just needs to reduce his calories

and he would lose the weight and that is true, but the problem is,

once you get into a vicious cycle of not being able to move, of being

immobile, of needing someone to help you to go and get some exercise,

then it gets very, very complicated to try and lose the weight.

For me, Les' story illustrates how obesity in the real world is

rarely straightforward.

I used to turn to food for comfort

and every time I was depressed or something like that,

it would be straight to food

and I would try and make myself feel better,

but it was no good cos it was just making me bigger than better.

My mum killed herself and I managed to hold it together for a short

amount of time and then it was inevitable that I comfort ate.

I think what a lot of people who have never been overweight

don't realise is that food can actually be a bit of an addiction.

The problem with an addiction to food is that you can't just

quit cold turkey like you can if you're smoking or

if you're drinking cos you've still got to eat every day or you'll die.

Given the complexity of this obesity epidemic,

where DOES the fault lie?

It has been a long day's filming so far.

I am tired, I am hungry, and my day is not over,

I have still got another four hours' drive

before I can actually get home.

I'm going to need to get some food as fuel to get me home.

Ah-ha, here might be some options.

There we go, here is Domino's, Papa John's pizza...

I'd be kidding myself

if I said I wasn't secretly enjoying the prospect of this takeaway binge.

I am starving, it is time to eat.

OK, what do we have here? We have got...

I've got myself a fish burger.

I've got myself a large fries.

And I have got myself apple pie,

lovely apple pie.

Now I'm going to open some sweet-and-sour sauce

to go with my chips.

Because who doesn't like some highly refined carbohydrates

and sugar, overly sweetened, to go with fried goods such as a chip?

Fan...

tastic.

It's actually fantastic, I do like it.

'To burn this lot off, I would have to walk for nearly four hours.

'But with the long drive ahead, that is not going to happen.'

I have fallen into the classic trap of needing food

when you're in a rush and when you need something quick.

And what do they tend to be? Highly processed, the fish is fried and...

And what am I doing? I am doing this because this is what is available.

This would not have happened before, I mean, 10,000 years ago

on the Serengeti when you are trying to pull back an antelope.

It would have cost you 2,000 calories to get the antelope.

We like to think that we have full control over the decisions

we take about our food.

"I control what I eat, I am a human being, I have free will."

The problem is, our urge to eat, particularly in such

a high-energy-dense environment, is a product of thousands,

hundreds of thousands of years of evolution.

In the developed world,

we have never had so much available to eat and so little to do.

In the last 20 years, the number of takeaways has soared.

And research has shown that living and working near

a high density of takeaway outlets doubles your likelihood

of being obese.

So on this stretch of one high street in what may be

a typical town in the UK, I have counted eight takeaways.

And this is what we would call an obesogenic environment.

And we are susceptible to it, there is a mismatch

between a brain that thinks we are still supposed

to be putting on energy because we might starve at any point

and an environment which encourages our baser instincts

in order to eat more.

And some people seem to be affected by these instincts more than others.

They find it particularly hard to resist

the temptation of calorie-rich food.

My favourite naughty snack that I find very hard to resist

has got to be Mars ice creams.

Cakes.

Cakes and doughnuts and... custard slices.

Sausage rolls, pies, pasties.

If I am at a buffet, don't even think about getting any Doritos,

because I will be there just shovelling them into my face.

-LAUGHING:

-I love them so much.

I believe that genetics play an important part in the reasons

why some people eat more than others.

Some cake for you.

-Oh, fantastic.

-There you go.

-Thank you so much.

And I have spent my career investigating

which genes are responsible.

We know that there are over 100 genes

that are linked to common obesity.

Of these, the one with the largest effect is a gene called

"fat mass and obesity-related transcript",

or FTO.

Now, all of us have FTO.

Some of us, however, have inherited

a slightly different version of FTO

which increases our risk of becoming obese.

'Half of the population have a version of FTO that contains

'just one small change.'

And what this means is that we are a kilo-and-a-half heavier

and 25% more likely to become obese.

'But roughly one in six of us are unlucky enough to have

'two small changes, or a "double-risk variant" of FTO.

'And they are more likely to want to eat more...'

They are on average 3kg heavier,

and critically, are 50% more likely to become obese.

'I have been studying the FTO gene for over eight years.

'And we now know that these genetic variations have been linked

'to changes in the brain which make it less sensitive

'to appetite hormones released from the gut and fat cells.

'This in turn affects how hungry we feel.'

I'm curious to see how this insight translates into the real world.

I want to find out if knowing if you have any FTO risk variants

can actually help with one of

obesity's biggest challenges - dieting.

Every time there has been a diet, I have tried it.

We have had the smelly cabbage diet in my life.

The Cambridge Diet...

I did the coffee, chewing gum and fags diet

in my late 20s.

None of them worked.

To be honest, any diet will work, providing you stick to it.

Today, I have come to Colchester Town Hall

in Essex to meet a group of dieters

keen to find out more about their genetics.

For all of our group they ask a really simple question,

which is, "Why me?

"Why is it that I struggle with my weight when I see people

"all around me who clearly don't

"seem to have the same problems that I do?

"Is it that I am different in some way?"

And obviously, your DNA is a very good place to start.

I want to know if understanding their genetics can help motivate

this diet group to lose more weight.

You have to understand that the reason you guys are finding

it difficult is not because you guys are bad.

You are not bad, you are not lazy,

it is not because you lack willpower.

You guys are fighting your biology.

'Today, some of the dieters are finding out

'if they have any of the FTO risk variants.

'First up is Tina.'

Tina, you actually have two risk copies of FTO.

Oh... Right, OK!

Maybe that is why I have continually struggled with my weight

over the years.

-Susan, you also have two risk copies of it.

-OK.

'So Susan and Tina should be, on average,

'about 3kg heavier than a person with no FTO risk variants.

'But that doesn't mean they have to be.'

I always consider your genes to be like a hand of poker.

You get good hands and you get bad hands,

and you can only blame your folks for it.

But...

you can win with a bad hand of poker

and you can certainly lose with a good hand of poker.

So it depends how you play the cards.

It is more difficult, but you can win with a bad hand.

'Winning with a bad hand is all about understanding how

'obesity genes influence what we eat.

'They actually change the way your brain interprets the signals

'coming from your body.'

These genes, what they do is they make your brain slightly less

sensitive to the hormones.

So your brain thinks that A -

you have slightly less fat than you actually have,

and B - you ate slightly less than you actually thought

you did the last time round. Now, you don't

eat twice as much as the person next to you, that is not what happens.

You are eating 5% more, but 5% more every day of your life

adds up to a huge lot of difference

when you actually put it all together.

It is lunchtime, and a perfect opportunity to find out

if knowing they have any FTO risk variants influences

how much these dieters eat and what food choices they make.

Hi.

I have asked obesity expert Dr Tony Goldstone to help me

set up a rather unusual food demo to find out.

We believe that if you have a double-risk variant

it alters your brain structure and function.

And we know from our brain imaging in some other

genetic studies, that it may influence how the reward pathways

in the brain work, leading to people craving

and liking the high-energy foods much more.

Tony has asked our dieters to give each of the foods a taste score.

So what we're expecting is that those that have

the double-risk FTO variant will be much more likely to like the foods

high in fat and sugar, want to eat them and actually choose

to eat them when given an option of a different buffet.

That's the one.

What the dieters don't know is that Tony is also secretly taking note

of how much high-calorie creamy chicken soup

and ice cream they consume.

They are dieting, so they're very worried about gaining weight

and wanting to lose weight, so it'll be interesting to see

whether actually that alters the findings from what we expect.

After lunch, Tony comes clean to the group

and reveals some unexpected results.

So we have never done this experiment before with people

who know their genetics or who are dieting.

And although the numbers are small,

we have found some really interesting things.

We have found that those that have the double variant were

either much more likely to not have anything to eat

or were more likely to choose the low-calorie options.

And that suggests that if you know your genetic variant,

you are much more likely to maybe alter your behaviour to avoid

the high-calorie foods.

These surprising results offer unexpected hope for the dieters.

We expected the opposite,

we expected those with the double variant to actually eat

and choose more of those high-energy foods,

but the crucial difference here in this study is that

they actually knew what their genetics were.

It suggests knowing you have got a bad hand of obesity genes

CAN help dieters.

It is in my head now,

I have got to use that extra information that I have got.

Yes, I will use it and see if I can incorporate it

in any weight-loss plan.

It really helps to understand, perhaps, how for me,

as an individual, my biology is driving my weight,

and more importantly, what I can do about it.

Our experiment looked at just one meal.

But I'm excited by the idea that simply knowing you have

obesity genes can influence your relationship with food.

With further research, this could become a powerful tool

when it comes to losing weight.

Yet, oddly,

when it comes to finding out my own FTO status, I am undecided.

In spite of all of the resources at my disposal -

and these are the exact machines we use to make

genetic measurements - I don't know my FTO risk status.

Do I have one or two copies of the FTO risk variant?

Maybe it's because I am not obese - yet.

And I don't feel I need to know.

If, however, I have been struggling

with my weight all of my life,

maybe that would be different.

I believe the food-rich world we live in today puts

the small group of the population carrying the double-risk variant

of FTO at a disadvantage.

But it is not all bad news. We now know of one hidden benefit.

On the next leg of my journey, I'm going to meet someone whose story

is a great example of how exercise can exploit a bad genetic hand.

I am on my way to Merthyr Tydfil in Wales,

where, in the past, it has had the dubious honour of being named

the fattest town in Wales.

25-year-old Nathan Hewitt once hit the headlines as one of

Britain's most obese schoolchildren.

He has taken me to this cafe to show me

what he used to eat on a regular basis.

-Here you go.

-Oh, fantastic, thank you so much.

-Enjoy.

-Thank you so much.

-All right.

Gosh, the... The portions are very big here.

Yeah. This is something I would eat on a regular basis, like, every week.

-Really?

-Yeah. Probably every weekend.

That was me at the age of 15 there. At my heaviest.

And how heavy?

23st. Not long before I made the decision to lose weight.

When you look at these pictures now, how does it make you feel?

Looking at them now, I don't identify as this person any more.

This is someone completely different to the person I am today.

But at the same time, it is a sense of achievement.

I am living proof that, on some level, we can change.

'What has really impressed me about Nathan's transformation

'is that he was dealt a bad hand when it comes to his obesity genes.

'I have tested his genetics and discovered he has two copies

'of the FTO risk variant,

'making him 50% more likely to be obese.'

Quite, you know, strange

to be carrying a genetic that does predispose me for obesity,

yet still living my life today as someone I consider slim and healthy.

The slim and healthy Nathan of today is the result of a hard-fought battle

to change unhealthy childhood habits.

I spent a lot of my young teenage years hanging around

in this area. I would eat junk food from the local corner shop there.

Crisps, chocolate, full-sugar Coke.

Constantly just snacking and...

What made you change?

Well, from the age of 11 to the age of 14,

every summer we would take a trip to Alton Towers.

I waited in queue for about an hour and a half,

looking forward to getting on this ride, and I couldn't fit on there.

The clamp wouldn't close down, and I remember being told,

"Sorry, mate, but you're going to have to leave the ride."

And that really was... That was hard for me.

This experience was the motivation

Nathan needed to change his diet and cut out the fatty foods.

And I lost the weight,

and the following year I went back on that ride, and I fitted on there.

But for me, what is really interesting is how big a role

exercise may have played in Nathan's transformation.

I opted for weights.

So altogether, when I finally reached my ideal size,

I had lost just over 11st in weight,

-I went from just under 23st down to 11st.

-11st?

-Yeah.

Nathan's combination of exercise

and FTO double-risk variant could be the key to his success.

Although scientists don't know why, they have discovered that

for those with a double FTO risk variant,

exercise can mitigate against the risk of obesity by 30%

compared to those with no risk variants.

It is an extraordinary finding.

Having the double FTO risk variant will increase

your likelihood for being obese, but the good news is

it also enables you to lose more weight if you exercise.

Well, I have just come back from a run on a lovely winter's morning.

I have been travelling so much lately I haven't got as much

cycling in, so I have been trying to supplement my exercise.

You see? I'm practising what I preach.

Trying to play my hand in life as best as I can.

Today, I am on my way to Southampton.

I have heard about new genetic discoveries that could have

serious implications for obesity in generations to come.

These babies are just a few hours old.

But it is possible that some of them

are already set on a path to obesity.

According to Professor Keith Godfrey,

it is not only down to the genetics they have inherited,

but also how genes are switched on or off during life in the womb.

We have always known that a mother's nutrition and lifestyle

is really important for the growth and development of her baby.

What we know now is it has a long-term effect on the health

of the baby, and part of that

includes a big predisposition to obesity.

Keith's research suggests foods that releases sugars quickly into

a pregnant mother's circulation can have a lasting impact

on their baby's weight.

These high sugar levels flow across the placenta and affect

the way in which the unborn baby's genes are turned on or off.

There are switches, chemical switches,

on the DNA which are influenced by the mother's sugar levels

and her diet, which tell one cell to be a muscle cell

and another cell to be a fat cell.

And when there are excessive amounts of sugar

coming across the placenta, then there is an excess of fat cells.

And that excess fat cell complement, it's with you forever.

According to Keith, these effects are associated with more than

a fivefold increase in the risk of childhood obesity.

While the months in the womb are critical for

the next generation's future risk of obesity,

scientist believe that there may be another window of opportunity

to stop the obesity epidemic,

long before the babies are even conceived...

..the teenage years.

This is University Hospital Southampton's LifeLab.

Today, a group of schoolchildren are analysing DNA samples that

illustrate how diet and lifestyle can

switch on or off a range of different genes linked to obesity.

The DNA the children are analysing belongs to parents

with healthy diets and parents with unhealthy diets,

and their respective babies.

LifeLab programme manager Kathryn Woods-Townsend explains the results.

OK, sample one is the DNA from a mother who had a healthy diet

while she was pregnant, and the DNA from her offspring,

and you can see it is identical.

And then we have the DNA from a mother who didn't have such

a healthy diet, and the DNA from her offspring, and what do you notice?

The patterns are different.

The changed pattern means that the baby's gene has been altered

by the mother's poor diet, putting them at greater risk of obesity.

And it is not just expectant mums that can

influence their unborn child's risk.

It is really important for us to keep the boys engaged

and show that actually, they are just as crucial in this process.

So here we have DNA from a father who had a healthy diet,

and his offspring's DNA.

DNA from a father who had an unhealthy diet,

and his offspring's DNA.

And again, you can see that the patterns are different.

So at a really simple level the message we are trying to get across

is that actually, what you do during your life can change your DNA.

But not only for yourselves, but also for your future families.

Not trying to scare you guys.

LAUGHTER

It is kind of scary, but then you can also use it as a motivation

to maybe eat healthy or be a bit more active in your lifetime.

What an absolutely inspiring day.

It was fabulous to see these kids engage with science,

engage with their health, and at this early stage in life,

when they can do something about it before they become unhealthy,

before they become obese. As a scientist, I love this place.

As a parent, I love this place.

Educating the next generation is undoubtedly a positive step

towards stopping obesity.

But what are the options now?

The only treatment proven to be effective for

sustained weight loss is bariatric surgery.

This is when the stomach is reduced in size,

and in some cases, the intestine is re-routed as well.

I am here to meet Philip.

He had bariatric surgery last year,

and I want to find out what difference it has made to his life.

Coach driver Philip Perrot is keen to show me

what he used to be able to eat before his operation.

-This is what I used to eat.

-Oh, my goodness.

As you can see, you have got the steak and kidney pie,

double portion.

Double chips - lovely.

And then munch my way through a box full of cream cakes.

Generally 10 to 12 a day.

That was a general lunch for me.

Oh, my goodness.

But now, if I am lucky, you can take all that away,

and at a push, I might be able to eat all that.

I think I would probably only manage half of the portion

here of the steak and kidney pie, a third of the chips,

and I would struggle to get through one cream bun.

-But which one would you like?

-The one with the jam.

Philip had a gastric bypass operation.

Typically these procedures reduce the stomach size

from a capacity of 900ml to just 30

and bypass more than a metre-long section of small intestine.

This major surgery had a dramatic impact on Philip's appearance.

This one is from 1999. When I was with my eldest son.

-Svelte(!)

-Gosh.

And the second one is approximately two years later, about 2001, 2002.

That is not you!

That is, I'm afraid. That is me.

How heavy were you?

I would reckon I weighed about 25st at my heaviest,

but now I am roughly 15st. That is a 10st loss.

How has your life changed, then, after surgery?

I am fitter than I ever have been.

I don't snore so much - that was a big bonus.

I'm actually still classed as a type 2 diabetic,

although instead of having the 15 or 16 tablets that I used to

take per day, I am not actually taking any medication now, at all.

Surprisingly, Philip's dramatic health benefits and weight loss

are not just thought to be the result of his reduced stomach.

Scientists now know that surgery also alters the release

of hormones, which in turn has a powerful influence on appetite.

You know, I am genuinely shocked by the amount of food that

Philip used to be able to eat in one sitting.

And to hear about his staggering change

in appetite before and after the surgery.

'But bariatric surgery is expensive and not without risks.'

The challenge is for scientists to try and control

the levels of these hunger hormones, but without the surgery.

Believe it or not,

scientists are already on the brink of doing just that.

It is a treatment that has been dubbed in the press

as a "miracle jab" that could help up to 15 million people.

If the scientists offered me an injection and said,

"We guarantee this will make you thin", obviously I would take it.

Oh, my gosh. Tell me more!

SHE GASPS

Please! I would love, love, love the injections.

I have come to Hammersmith Hospital in southwest London.

Here, Professor Steve Bloom and his team

have created a cocktail of hunger hormones

that mimics the physiological after-effects

of gastric bypass surgery.

Surgery is potentially dangerous.

Maybe a half percent of people undergoing it

will die from the procedure.

A lot of complications, it is expensive,

most of us don't want surgery, so it would be very nice to have

some sort of injection which will do the same thing.

'Professor Tricia Tan is overseeing the trial.'

So, today we have two volunteers who have come in,

and they will receive a triple gut hormone infusion.

And what we will be looking at is how these hormones affect

their appetite and food intake, and compare this with their

previous visits, where they did not

receive any hormones but just a placebo.

These volunteers are part of a larger study.

This is Giles.

Nice to meet you, thank you for...

So Fred is one of our study volunteers.

-I snack a lot.

-You snack, you are a grazer?

Just going to pop that here.

'The device will pump a steady stream of hormones into Fred's body,

'which Tricia hopes will influence his appetite.'

-OK, see you later.

-Thanks a lot, Fred.

-OK.

'The hormones are given four hours to

'take effect before the volunteers are offered lunch.'

There you go, we can now prepare the food.

-Essentially, we just use ready meals.

-OK.

-Is this one person's portion?

-Yes.

-Why are there three?

We have to present them with food in excess.

More food than they can actually eat.

'The amount of food left over will allow Tricia to establish

'how effective the hormone injection has been on their appetites.'

Chicken tikka masala, special du jour.

OK, Fred, here is the lunch, please eat until you

are comfortably full and then buzz on the buzzer

-when you are done, OK?

-OK.

Hi, Paul, here is your lunch.

Paul and Fred press their buzzers when they are comfortably full.

Thank you.

-Thank you very much.

-Thank you.

Well, it looks like there is quite a bit of it there.

I guess we won't know until we do the final weighing, but...

(maybe it's worked.)

OK. This is...

Tricia compares the amount that

Paul and Fred have eaten today with the last time

they came into the hospital, when they were given a placebo injection.

-For Paul, he has eaten 240 calories less.

-240 calories less?

That's right.

-And it's a 22% reduction.

-Oh, OK.

And Fred, again, 203 calories less than his first visit.

-That is around 17% reduction.

-Oh, gosh!

Over a lifetime, say over even a few months,

the amount of weight you would lose would be incredible.

That's right.

'It's extraordinary to think that the hormone injection has tricked

'Paul and Fred's brains into thinking their stomachs are full.'

How full are you feeling now?

-Pretty full.

-Yeah?

-I feel comfortably full.

Not hungry at all.

-Fantastic.

-You're welcome.

'This change in appetite is typical of other volunteers in the trial.'

With the injections of the hormones, the patients are eating

up to 30% less than when they are not given the hormones.

To be a really effective treatment for obesity,

the goal is to create a hormone injection that doesn't just

reduce the appetite one meal at a time, but lasts for a whole week.

Fast forward ten years, obesity won't be a problem,

They'll have the injections, they will be painless,

no side-effects, and actually really inexpensive and freely available.

So I think this is going to make an enormous difference.

But for some, this miracle injection might not be the full answer.

The problem is, I don't always eat when I am hungry.

A lot of times I will eat

because I am sad or bored or really happy with myself.

So I am not sure that an appetite suppressant would

really work for me anyway.

For this leg of my road trip, I am in America.

There has been a story in the press over here that is

so extraordinary I have travelled over 3,000 miles

to Providence, Rhode Island to find out more.

Because I am making a film about obesity, I think it is

inevitable that I was going to end up back here, in the United States.

The ground zero, almost, of the problem.

But the story I am investigating is not your classic tale

of becoming obese through eating too much.

It is an intriguing mystery that takes me

right outside my field of expertise.

I am entering the hidden world of gut bacteria.

It is estimated that over 100 trillion bugs live inside our guts.

There are over 1,000 different species,

and only recently scientists have begun to understand

the complex relationship these bugs have with our health.

In the last few years, the spotlight has turned to obesity.

And the press has had a field day with the idea that the

bacteria living in our guts could affect our waistline.

If the story is true, it could hold some potentially novel

and really quite interesting clues as to one of the causes of obesity.

The person I have come all this way to meet

put on over 4st in two years.

Now, there is nothing especially remarkable about that,

but what IS unusual is the way

she is thought to have gained the weight.

HE RINGS DOORBELL

-Hi!

-Hi, how are you?

-You must be Teresa.

Yes, Teresa, nice to meet you.

-Hello, I'm Giles, nice to meet you. It's cold.

-Yes, very.

Teresa wants to show me

how much her body has changed in the last few years.

-This here is me in 2006.

-Oh, wow.

-How heavy were you here?

-I was 123lb.

-I look great, huh?

-You look great now.

-And this one was me in 2012.

-Wow.

2013 is when I was at my highest,

and you won't find a picture of me at that point!

Teresa's weight gain started shortly after

she was cured of a painful

and debilitating infection in her gut,

caused by the bacteria Clostridium difficile,

or C.diff for short.

It caused a lot of pain, so I was in pain a lot of the time,

almost like keeled-over pain.

And I was physically exhausted from it.

It was a very scary thing, very real, yeah.

Her cure was an unpalatable-sounding treatment called

faecal microbiota transplant.

It involves transplanting faeces from

a healthy donor into the unwell patient.

Eugh!

Probably what most people think when they hear it,

it sounds a little gross.

But it is exactly that, the idea is, with C.diff,

it's a bad bacteria, so inside of my intestines, the C.diff,

the bad bacteria, just overpopulated.

So, in order to get rid of it, the idea is I would take

a donor's faeces, which, at the time, I used my daughter's.

And the good bacteria from my daughter's faeces would

overpopulate the bad and clear it up.

And literally, like this,

the next day, it was amazing. It was unbelievable.

I got instant, instant, instant relief from my symptoms.

While she was cured of her C.diff, Teresa's recovery came

with an unwanted side-effect.

Initially, everything felt great, for about six months,

and then I noticed my clothes weren't fitting me the same.

So I had had this slow, but gradual weight increase.

I literally went from a size two, size four, size six,

size eight, size ten... You know what I mean? 12, 14...

And before I knew it,

I had about a 60lb weight increase within a matter

of two to three years.

Teresa is convinced that her weight gain was

caused by the sample of faeces her daughter donated.

I have never had a problem with my weight before,

so I honestly think that there was something in

my daughter's faeces that was causing me to gain the weight.

It is very frustrating when you're used to looking

and feeling a certain way,

and then something like gaining weight

can make you feel and look completely the opposite.

The idea of bacteria in faeces causing weight gain

may sound far-fetched.

But the scientific detective work of Teresa's doctor

unearthed some tantalising evidence.

Well, when she initially came back,

I didn't at first recognise her, even.

She looked so different than I remembered her.

Just like Teresa, Dr Colleen Kelly believes that

the donor faeces holds the key to the mystery.

The mother was slender and fit, and the daughter was overweight.

Quite overweight.

We didn't weigh her or measure her,

but one would say maybe, possibly obese.

At the time, we had some health criteria

and some screening we would do, but obesity wasn't one of them.

And a study published in 2013, looking at an unusual set of twins,

and the effect that their faeces had on mice,

seemed to provide the missing piece of the puzzle.

They looked at twins who were discordant for obesity.

So these were identical twin females,

where one twin was obese and the other twin was lean.

They would basically take stool from the obese twin and stool

from the lean twin and then transfer that stool into germ-free mice.

Mice that got stool from the obese twin developed more weight gain,

more body fat,

and those that got stool from the lean donors stayed lean.

I think it was that landmark study that got a lot of press

that really made me think, "Wow, is this what happened to Teresa?"

We cured her C.diff, but did we transfer some

bacteria from the daughter that may have promoted obesity?

I wish that there was a way that I could undo it, some way that I could

find a lean donor for her, and do a faecal transplant with a lean donor.

To see if it would reverse or make any sort of effect.

The Food and Drug Administration in America won't allow Colleen to

do this, but an hour up the road at Brigham Women's Hospital in Boston,

a human trial is about to start that could offer some hope.

I'm just inserting the scope now into the rectum.

-You OK, Jen?

-Yep.

-Great.

And now what I'm going to be doing is

making my way around the colon until I get to the end.

'Today, Dr Jessica Allegretti is treating a patient with C.diff,

'using a faecal microbiota transplant.

'It is the same procedure that she will use in the upcoming trial.

'But in the trial,

'instead of transferring faeces into sick C.diff patients,

'she will be treating otherwise well obese patients.

'And the faeces will come from donors

'with one key thing in common.'

So what we are targeting are donors who are very lean,

donors with BMIs of less than 20, somewhere between 17 and 20,

who are otherwise healthy and very metabolically healthy.

'Jessica hopes that the lean donor faeces will be packed

'with fat-busting bacteria.'

-How many bacteria do you think are in 250ml?

-Oh, billions.

Billions on billions.

'The aim of the trial is to discover if the lean donor faeces will

'influence the obese patient's hormones that affects hunger.'

So what we're hoping the faecal transplant will do

is, by giving good bacteria to patients with obesity,

we'll be increasing certain levels of bacterial by-products that

therefore influence hormonal levels in the gut and actually help people

to feel more full, and therefore will influence weight loss.

This is the last little bit of push, OK, Jen?

Just going to give you a little bit more meds, OK?

You're doing awesome.

So we have just entered the large intestine

to the small intestine, and this is where...the part of the intestines

where the hormones come from that influence food intake.

That make you feel fuller.

Stool's coming out, it kind of blurs your vision.

-So we're just kind of bathing the wall with that donor material.

-OK.

'And there's one hunger hormone in particular that Jessica

'and the team will be keeping a close eye on - GLP-1.'

So what we are hoping to see is that GLP-1 rises significantly

after faecal transplants in these patients,

and we're using that as sort of a surrogate marker for weight loss.

And, if that is what we see, then I think it will be

good evidence to support a much longer study that will be needed

to really assess if this could work for weight loss.

-Is that it?

-Yeah.

-Oh, good, we're done.

Oop.

That was amazing to watch.

It is amazing to think that one person's faecal matter,

one person's poop, can then help someone else feel better.

If we can imagine that, in the future, this could be

therapy for obesity, well, how wonderful would that be?

The outcome of the trial remains to be seen,

but even if successful, using faeces to deliver

a full overhaul of a person's gut bacteria remains a radical solution.

Which is why some scientists are taking a different approach.

They are attempting to isolate individual bacteria

linked to weight loss.

For the final leg of my road trip, I am back in the UK,

at St Thomas' Hospital in London.

Professor Tim Spector is using faeces

collected from thousands of sets of twins to

try and identify which bacteria might make you thin.

Twins are the perfect way to find out

if something is due to nature or nurture.

Whether it is inherited or due to our environment.

What Tim has discovered about the bugs living inside us

could revolutionise the way we treat obesity.

There was this one bug, which stood out as the most heritable,

which turned out to be extremely interesting in terms

of its effect on body fat.

Of all Tim's twins, non-identical Wendy and Carol

have one of the largest weight differences.

Wendy weighs 14st, and Carol just eight.

Tim thinks that the bacteria

in their faeces could provide clues as to their large weight difference.

Thank you very much, fantastic.

When we looked at thousands of our twins,

the one thing that stands out between

the fatter twin and the thinner twin

was this funny microbe with a strange name,

called Christensenella.

And about one in ten people have it and, if you have it,

-large amounts of it, you rarely get fat.

-Really?

-But...

-And one of you has got it. And guess...

Guess who it is.

So Carol ends up having large proportions, about 5%,

of Christensenella in her gut microbes.

Whereas you have only got a tiny fraction,

we can just about detect it.

-Oh, wow.

-But it is not doing very well in you.

-Oh, is it not?

Is there anything I can do to increase it?

'Luckily for Wendy, Tim believes there is.

'While her genetics may not have helped her Christensenella flourish,

'what she eats could.

'Studies have not yet been done to investigate which foods

'increase Christensenella numbers.

'But Tim believes that the right diet could encourage a broad

'range of bacteria to grow.'

The more diverse the foods, the more high-fibre the foods,

the more species of microbes you're going to get

and the more likely you're going to get the good ones

rather than the bad ones flourishing.

The base of this is really an old-fashioned Mediterranean diet,

but without the pasta and the pizza.

So it is plenty of fruit and veg, and you have got artichokes here.

-Oh.

-They are fantastic fertilisers for your microbes.

It's also some things that you may not have thought of necessarily

as healthy, you got dark chocolate - it is actually good for you.

In moderation.

Full-fat yoghurts, that is going to be really good

for your microbes, because that contains healthy microbes,

which energise your existing ones.

Tim believes that manipulating these bugs opens up

a whole new field of treatment for obesity.

We are in the dawn of a whole new year of discoveries,

and working out what makes these bugs tick

and how they interact with us, not just this Christensenella,

but there's likely to be other microbes just like it

that are protective,

and, if we can start to manipulate those through our diets,

it's an extremely safe and potentially extremely effective way

of fighting both obesity and its consequences like diabetes.

I have just had a fascinating insight

into the mysterious world of our gut bacteria.

I now know that your genes, your environment, your diet

all play critical roles in the type of bugs that will be in our gut.

But it's still early days for the scientific research.

Only time will tell

if these bugs can lead the way in our fight against obesity.

My road trip is over, and it is time to get back to the lab.

I have covered thousands of miles

and eaten more fast food than I would probably care to admit.

I think one of the most precious things

I will take away from this road trip is being able to meet people

who are actually really quite debilitated by obesity.

And it has given me an insight into obesity within the real world.

It has really motivated me to go back into the lab,

to try and redouble our efforts.

Based on a lot of the cutting edge stuff we have seen on this trip,

I am confident that this battle against obesity will be won one day.

In the meantime, I will continue to make my own

small changes in a bid to get my waistline back into shape.

For example, I have got myself my normal morning cup of coffee

and, instead of a cappuccino,

I have got myself a black Americano with no milk.

So a lot fewer calories and every little counts.

I know that making changes like this is harder for some than others,

but over time, the hardest-won battles

can reap the sweetest rewards.

At my heaviest, five years ago, I was 23.5st and had a BMI of 52.

I am currently about 15st.

I have lost 5st and I now feel amazing.

I was 25st, I've actually now got down to 20.

In 32 weeks, I have lost 4.9st.

I'm a totally different person, I actually now

take the dogs for a walk, which I have never been able to do.

My life has just totally changed in those past five years.

The people who haven't seen me

in those five years just don't recognise me at all.