0:00:03 > 0:00:04As a nation, we are slowly
0:00:04 > 0:00:08but surely getting fatter.
0:00:08 > 0:00:11We're all eating well.
0:00:11 > 0:00:13Maybe too well.
0:00:14 > 0:00:18I'm Gabriel Weston and I'm a surgeon and writer.
0:00:19 > 0:00:23I think this obesity problem has become bad enough
0:00:23 > 0:00:26to be called an epidemic
0:00:26 > 0:00:28But it's a puzzling one.
0:00:28 > 0:00:30Here's the mystery.
0:00:30 > 0:00:32We all live in the same environment,
0:00:32 > 0:00:35surrounded by delicious food 24/7.
0:00:35 > 0:00:37But we're not all the same shape.
0:00:37 > 0:00:41Some of us balloon, some of us get a bit chubby,
0:00:41 > 0:00:43and some of us just stay thin
0:00:43 > 0:00:47What is it about this epidemic that operates so randomly?
0:00:47 > 0:00:50For the unlucky majority,
0:00:50 > 0:00:54nothing seems to stop the pounds piling on.
0:00:55 > 0:00:59We ask patients to go away, eat a little bit less food,
0:00:59 > 0:01:02do more exercise, but it hasn't worked for the last 2,000 years
0:01:02 > 0:01:06and we need to really come up with some better ideas right now.
0:01:06 > 0:01:09It's tempting to see this epidemic
0:01:09 > 0:01:12as a failure of willpower.
0:01:12 > 0:01:17It's just something you want, you need, you know? It's fat.
0:01:18 > 0:01:21But the latest research that I've seen
0:01:21 > 0:01:26has forced me to change my mind.
0:01:26 > 0:01:31I'm pretty shocked to discover that my assumption of a lifetime,
0:01:31 > 0:01:36which is that I'm the size I am because of my character, is nonsense
0:01:36 > 0:01:41And this new science may hold important clues
0:01:41 > 0:01:44for fighting the fat epidemic.
0:02:03 > 0:02:07I've been working as a surgeon for over ten years.
0:02:11 > 0:02:14I love being in theatre. I've always enjoyed it.
0:02:14 > 0:02:18There hasn't been a week gone by when I haven't loved being here,
0:02:18 > 0:02:21and I can't completely explain why I do, to be honest.
0:02:21 > 0:02:26It's a chemical thing. It's a great place to be.
0:02:26 > 0:02:28I feel myself when I am here.
0:02:30 > 0:02:35I specialize in skin operations.
0:02:35 > 0:02:40Today, I'm removing small but potentially dangerous growths.
0:02:42 > 0:02:44Sore bit coming up now.
0:02:46 > 0:02:47Well done.
0:02:57 > 0:02:59If you feel anything sharp,
0:02:59 > 0:03:02let me know and I'll give you some more local.
0:03:02 > 0:03:04We have a number of cases,
0:03:04 > 0:03:09all of which are likely to be skin cancer.
0:03:09 > 0:03:13They are either of the type that will just grow unless removed
0:03:13 > 0:03:18or even the type that can spread and kill people.
0:03:18 > 0:03:21The feeling that my surgical skills
0:03:21 > 0:03:24are helping to treat cancer is really satisfying.
0:03:25 > 0:03:29When I stick this knife into someone and they've got a skin cancer,
0:03:29 > 0:03:33I feel happy about what I am doing and I enjoy it.
0:03:35 > 0:03:37But there is one group of patients
0:03:37 > 0:03:40we seem unable to help as much as we'd like.
0:03:41 > 0:03:44These are the growing number of obese people
0:03:44 > 0:03:47who are now coming in for surgery.
0:03:48 > 0:03:52What we've been doing on this operating theatre
0:03:52 > 0:03:53this afternoon has been quick.
0:03:53 > 0:03:57We've seen lots of surgical patients really fast.
0:03:57 > 0:03:59But in hospitals all over the country,
0:03:59 > 0:04:03obese patients are bringing surgical operations
0:04:03 > 0:04:04to a compete standstill.
0:04:04 > 0:04:08They complicate the surgical process at every level.
0:04:08 > 0:04:10They have tons of other illnesses
0:04:10 > 0:04:12which make their surgical diseases complex.
0:04:12 > 0:04:15They're extremely difficult to anaesthetise
0:04:15 > 0:04:17and difficult to operate on as well.
0:04:18 > 0:04:22This makes surgery riskier for thousands of patients every year
0:04:24 > 0:04:27But it's not just a problem in surgery.
0:04:27 > 0:04:30I'm also a mother, so I'm concerned
0:04:30 > 0:04:33how this explosion of obesity
0:04:33 > 0:04:36will affect our children and their children too.
0:04:38 > 0:04:42What I want to do is look at some of the interesting new research
0:04:42 > 0:04:46that's trying to explain what obesity is all about
0:04:46 > 0:04:49and some of the ways we might go about
0:04:49 > 0:04:51fighting this fat epidemic.
0:05:06 > 0:05:09On the face of it, there seems an obvious reason
0:05:09 > 0:05:11why the last 20 years has seen our weight soar.
0:05:13 > 0:05:16We're eating more food than we need,
0:05:16 > 0:05:19because it's more easily available than ever before.
0:05:21 > 0:05:23I'll just try a little bit of this.
0:05:27 > 0:05:28That is delicious.
0:05:29 > 0:05:32Here in the modern developed world, food is everywhere
0:05:32 > 0:05:35and it's rich in calories.
0:05:38 > 0:05:41Spicy sausage.
0:05:41 > 0:05:43- Mm, lovely.- It's packed with flavour.
0:05:45 > 0:05:49Some estimates suggest that most of us are now eating
0:05:49 > 0:05:53over 200 more calories than we need every day.
0:05:53 > 0:05:55And the truth is it's the fatty,
0:05:55 > 0:05:59calorie-rich foods we love the most
0:05:59 > 0:06:01Wow! A Portuguese custard tart.
0:06:01 > 0:06:06This is literally my favourite food on earth. Here I go.
0:06:12 > 0:06:13It's too good for words.
0:06:18 > 0:06:21What I see at this market
0:06:21 > 0:06:24is the collision of two different worlds.
0:06:24 > 0:06:28Our bodies evolved in a prehistoric world where calories were scarce,
0:06:28 > 0:06:33hence our love for the taste of the fatty stuff.
0:06:36 > 0:06:39But our developed world is awash with food.
0:06:39 > 0:06:42When our primitive biology feeds so richly,
0:06:42 > 0:06:45the result for many is obesity.
0:06:48 > 0:06:51In fact, nearly a quarter of the adult population
0:06:51 > 0:06:53are now clinically obese.
0:06:55 > 0:06:58So is there anything we can do about it?
0:07:02 > 0:07:04To answer this question,
0:07:04 > 0:07:07I want to start by explaining
0:07:07 > 0:07:10how the obesity epidemic is actually doing us damage.
0:07:10 > 0:07:13I want to talk about fat.
0:07:21 > 0:07:26And as a surgeon, I can take a look at fat from a unique perspective.
0:07:26 > 0:07:29From the inside out.
0:07:29 > 0:07:31I've come to the Royal Veterinary College
0:07:31 > 0:07:34to show you something rather surprising.
0:07:35 > 0:07:38This isn't exactly the kind of anatomy I'm used to,
0:07:38 > 0:07:42but it's as close to human as I'm going to get.
0:07:49 > 0:07:52Food is a biological necessity.
0:07:52 > 0:07:56And at the most basic level, fat is too.
0:07:56 > 0:07:59It's just the body's way
0:07:59 > 0:08:01of storing food between meals.
0:08:01 > 0:08:04So fat is not all bad.
0:08:11 > 0:08:15Now I'm cutting through the epidermis,
0:08:15 > 0:08:17the dermis, down onto the hypodermis,
0:08:17 > 0:08:19which is the subcutaneous fat.
0:08:19 > 0:08:24It's quite hard work in a pig compared to a human being.
0:08:24 > 0:08:29This layer of white, dense tissue here
0:08:29 > 0:08:31is the subcutaneous fat
0:08:31 > 0:08:35and this is one of the places where this pig, as well as you and I,
0:08:35 > 0:08:38store our fat.
0:08:38 > 0:08:41Subcutaneous fat can do this because it's made up
0:08:41 > 0:08:42of billions of special cells
0:08:42 > 0:08:46that are capable of expanding and contracting.
0:08:46 > 0:08:49So this fat is actually protecting us
0:08:49 > 0:08:51during periods of starvation
0:08:51 > 0:08:54You might think that when a person becomes overweight,
0:08:54 > 0:08:57it's this stuff making them ill.
0:08:57 > 0:09:01But actually subcutaneous fat is not where the problem lies.
0:09:01 > 0:09:04Now if I go deeper into the pig's body,
0:09:04 > 0:09:08I find a different, more dangerous kind of fat.
0:09:08 > 0:09:12I have to say that having not done any dissection of anything dead
0:09:12 > 0:09:15in over ten years, it's a real pleasure
0:09:15 > 0:09:19just to be able to dissect a carcass like this.
0:09:22 > 0:09:24What I'm looking for now is something we call
0:09:24 > 0:09:29visceral fat, which we've all got some of.
0:09:29 > 0:09:30OK, I'm in.
0:09:33 > 0:09:36Oh, my goodness. That is just too cool
0:09:39 > 0:09:43This visceral fat, gathered around the most sensitive organs,
0:09:43 > 0:09:47accumulates when we eat more than our bodies can handle.
0:09:47 > 0:09:52There's lots of visceral fat here.
0:09:52 > 0:09:57There's a bit of fat just coming off the bottom of the liver there.
0:09:57 > 0:09:58That's intra-abdominal fat.
0:10:01 > 0:10:05Too much of this visceral fat can lead to a surge in cytokines,
0:10:05 > 0:10:08chemicals which have been linked
0:10:08 > 0:10:10to diabetes and heart disease.
0:10:10 > 0:10:13We can't live without fat,
0:10:13 > 0:10:17with all the important roles it performs. But if we overload it
0:10:17 > 0:10:19so that it can't work properly anymore,
0:10:19 > 0:10:22we can't easily live with it either.
0:10:24 > 0:10:29So, simply put, too much visceral fat can make us sick.
0:10:35 > 0:10:39Everyone knows that how much fat you put on
0:10:39 > 0:10:42starts with a few basic decisions.
0:10:42 > 0:10:44What to eat.
0:10:44 > 0:10:46When to eat.
0:10:46 > 0:10:48How much to eat.
0:10:48 > 0:10:50When to stop.
0:10:52 > 0:10:57But what is it in our bodies that is shaping these decisions?
0:10:57 > 0:11:00And how can we control it?
0:11:05 > 0:11:09I've come to meet Dr Carel Le Roux, one of the world's leading
0:11:09 > 0:11:14obesity scientists, who may have come up with some of the answers.
0:11:14 > 0:11:17He's a former athlete turned medic,
0:11:17 > 0:11:19whose own life story helped focus his work
0:11:21 > 0:11:24So, what got you interested in obesity to start with?
0:11:24 > 0:11:27Obesity is such an important disease at the moment.
0:11:27 > 0:11:30There are so many people suffering from it,
0:11:30 > 0:11:33and yet we as doctors are not able to help them.
0:11:33 > 0:11:38We ask patients to go away, eat a little bit less food,
0:11:38 > 0:11:41do more exercise, but it hasn't worked for the last 2,000 years
0:11:41 > 0:11:45and we need to really come up with some better ideas right now.
0:11:48 > 0:11:53His work started with an interest in what was controlling his own weight.
0:11:53 > 0:11:56As a champion shot-putter,
0:11:56 > 0:11:59he was continually trying to bulk up.
0:11:59 > 0:12:01But however much he ate,
0:12:01 > 0:12:05he couldn't seem to gain as much weight as he needed.
0:12:06 > 0:12:09I was very motivated. I had a lot of willpower.
0:12:09 > 0:12:13I wanted to get my weight up but, despite my best efforts,
0:12:13 > 0:12:17my body would just not allow me to get out of this set point
0:12:17 > 0:12:18where it wanted me to be.
0:12:21 > 0:12:24His group started to investigate
0:12:24 > 0:12:26what process in our bodies
0:12:26 > 0:12:30might be controlling this set point in our weight.
0:12:30 > 0:12:34And they started to look at some of our body's chemical messengers
0:12:38 > 0:12:41A group of proteins which course through our body
0:12:41 > 0:12:44every day, influencing our behaviour.
0:12:48 > 0:12:50They're our hormones.
0:12:54 > 0:12:58Hormones tell the body when to fight or to flee.
0:12:58 > 0:12:59How to repair itself.
0:12:59 > 0:13:03They even tell our cells when to die.
0:13:04 > 0:13:08Then ten years ago, Le Roux was part of a research team
0:13:08 > 0:13:10that made a startling breakthrough.
0:13:11 > 0:13:15They discovered two new hormones, ghrelin and PYY,
0:13:15 > 0:13:20that together seemed to control appetite and weight.
0:13:20 > 0:13:24There was a hormone that actually made us hungry.
0:13:24 > 0:13:28In 2002, we discovered there was a hormone that made us full.
0:13:28 > 0:13:31how did the discovery of these two new hormones
0:13:31 > 0:13:34influence the science of obesity?
0:13:34 > 0:13:38It completely opened up a new chapter because for the first time,
0:13:38 > 0:13:41we understood that the gut can actually talk to the brain
0:13:41 > 0:13:44and influence how hungry you are or how full you are.
0:13:44 > 0:13:47So now we understood why it is so difficult
0:13:47 > 0:13:52for patients who are overweight to actually change their weight,
0:13:52 > 0:13:55because these hormones work against them.
0:13:55 > 0:13:59I have to admit, I feel a bit sceptical about this idea
0:13:59 > 0:14:02that an overweight person is overweight
0:14:02 > 0:14:06because of their hormones, but I'm not overweight because of mine.
0:14:06 > 0:14:09Well, why don't we invite you to come to the hospital?
0:14:09 > 0:14:12We'll do an experiment where we put your willpower
0:14:12 > 0:14:15against your hormones and see which comes out best.
0:14:22 > 0:14:25Today I'm hoping to find out how my hormones
0:14:25 > 0:14:28might secretly be controlling my appetite.
0:14:28 > 0:14:32If Dr Le Roux can prove to me that I am at their mercy,
0:14:32 > 0:14:34I'll have to think again
0:14:34 > 0:14:37about what's causing people to over eat.
0:14:37 > 0:14:41- Can I take your coat?- Yes, thank you very much.- Grab a seat.
0:14:41 > 0:14:42Have you eaten anything?
0:14:42 > 0:14:46I think the last time I ate anything was 9pm yesterday evening.
0:14:46 > 0:14:49All right. You're going to have some breakfast. Eat as much as you want.
0:14:49 > 0:14:52You'll have a spread, so you can choose. I'm then going to take
0:14:52 > 0:14:55some blood tests from you. What we're going to determine
0:14:55 > 0:14:58from the blood tests is how does the gut talk to the brain.
0:14:58 > 0:15:02It all starts simply enough
0:15:02 > 0:15:06Somewhere in my blood are my appetite hormones,
0:15:06 > 0:15:08helping me to decide what to eat.
0:15:10 > 0:15:14Oh my goodness, look at that. It's a feast!
0:15:14 > 0:15:17We also have something in the microwave for you.
0:15:23 > 0:15:25Ooh, that looks really delicious.
0:15:25 > 0:15:27I think you've hit the jackpot there.
0:15:37 > 0:15:39I am now primed for the experiment.
0:15:39 > 0:15:42Or at least I thought I was.
0:15:42 > 0:15:44Well, we've tricked you a little bit,
0:15:44 > 0:15:49because what we're going to ask you to do now is not to eat again
0:15:49 > 0:15:52- until breakfast tomorrow. - Wow, OK!
0:15:52 > 0:15:54It's not what I was expecting. If I'd known before,
0:15:54 > 0:15:57and this is why you're telling me now, I would have eaten double.
0:15:57 > 0:16:00Your body will be able to cope with the fast,
0:16:00 > 0:16:03but it will actually psychologically
0:16:03 > 0:16:05bring all types of things to the fore.
0:16:05 > 0:16:10Because, of course, if people become hungry, they become ratty.
0:16:12 > 0:16:15So the next 24 hours were to be the battleground
0:16:15 > 0:16:20where my hormones and my willpower would fight.
0:16:21 > 0:16:23After just a few hours
0:16:23 > 0:16:26I notice my hunger returning, and it begins to affect me.
0:16:26 > 0:16:29I'm feeling very distracted by how hungry I am.
0:16:29 > 0:16:33I'm having to concentrate a bit harder
0:16:33 > 0:16:37on driving than I usually would.
0:16:37 > 0:16:40Because I'm not feeling that I can drive
0:16:40 > 0:16:42quite as well as usual.
0:16:46 > 0:16:50Later, I can feel the changing hormones
0:16:50 > 0:16:53really starting to alter my mood.
0:16:53 > 0:16:56I'm feeling grumpy now Really hungry actually.
0:16:56 > 0:17:01So I feel as if I want to make this as quick a visit as I can.
0:17:01 > 0:17:03And my judgement too.
0:17:03 > 0:17:07I'm going to stop and get some yoghurts.
0:17:07 > 0:17:09Ooh. I'm also feeling like
0:17:09 > 0:17:12I'm looking at them and feeling indecisive, which is not me at all.
0:17:15 > 0:17:17And as I began to get really hungry,
0:17:17 > 0:17:21food was all I could think about.
0:17:21 > 0:17:22Over here, they have the...
0:17:24 > 0:17:27The smell is just powerful and delicious.
0:17:27 > 0:17:31They made the roast chickens there.
0:17:45 > 0:17:497am. Nearly 24 hours since I last ate.
0:17:49 > 0:17:51And just one hormone measurement left
0:17:51 > 0:17:53before I can give in to my hunger.
0:17:53 > 0:17:55Morning! How are you?
0:17:55 > 0:17:59- I am ravenous.- Really? - And a bit tired.
0:17:59 > 0:18:03Well, let me take your coat and let's get right into the experiment.
0:18:05 > 0:18:08Dr Le Roux does the last blood test and I can finally eat.
0:18:12 > 0:18:14And I immediately tuck into
0:18:14 > 0:18:18the sweetest, fattiest food on the table.
0:18:18 > 0:18:22And I'm going to have my first bite of food in 24 hours.
0:18:25 > 0:18:30It was quite possibly the best meal of my life.
0:18:30 > 0:18:31It's really, really good.
0:18:33 > 0:18:35But what I'm really keen to find out
0:18:35 > 0:18:39is how my hormone results compare to those of an obese persons.
0:18:39 > 0:18:43Take a seat here. The results are in
0:18:43 > 0:18:47and the good news is that you're completely normal.
0:18:47 > 0:18:49- Great!- What we see
0:18:49 > 0:18:51that immediately when you've had your meal,
0:18:51 > 0:18:53your hunger hormone starts falling
0:18:53 > 0:18:56and then after a short period, it starts
0:18:56 > 0:19:01rising. And by the beginning of the next morning,
0:19:01 > 0:19:02it is incredibly high.
0:19:02 > 0:19:06Which is exactly how I felt. I was beside myself by then.
0:19:06 > 0:19:08And how about the fullness hormone?
0:19:08 > 0:19:10Looking at that, you see the opposite.
0:19:10 > 0:19:13Immediately when you eat, the fullness hormone shoots up.
0:19:13 > 0:19:15It makes you feel full,
0:19:15 > 0:19:17allows you to stop eating.
0:19:17 > 0:19:23And then it starts plummeting and it stays down for the whole duration.
0:19:23 > 0:19:26So how would that compare with the profile of someone who had...
0:19:26 > 0:19:28who was overweight or obese?
0:19:28 > 0:19:32With the hunger hormone, surprisingly,
0:19:32 > 0:19:37obese patients didn't have as much hunger as we expected.
0:19:37 > 0:19:41The hunger hormone never gets switched on
0:19:41 > 0:19:45and it stays at the same level throughout the day
0:19:45 > 0:19:49and then starts rising if we actually had to deprive them of food.
0:19:49 > 0:19:53So it's a little bit like a light shining dimly
0:19:53 > 0:19:56but where your light shines brightly,
0:19:56 > 0:20:00it gets switched off. When they eat the light stays on.
0:20:00 > 0:20:05So that constant nagging sensation remains throughout the day.
0:20:05 > 0:20:09Which is really interesting because not knowing about this hormone,
0:20:09 > 0:20:11what I expected was that you would tell me
0:20:11 > 0:20:17that someone who was overweight had a much, much stronger hunger hormone than I do
0:20:17 > 0:20:20but in fact what you're saying is that that's not the case.
0:20:20 > 0:20:25You're right and we were surprised until we looked at the fullness hormones
0:20:25 > 0:20:27and suddenly it started making sense
0:20:27 > 0:20:31because what you would see in somebody that is overweight,
0:20:31 > 0:20:34their fullness hormone only rises a small amount
0:20:34 > 0:20:36and then comes down again.
0:20:36 > 0:20:39So they actually never get the feeling of fullness.
0:20:39 > 0:20:45And you would hear that very often speaking to people who are overweight.
0:20:45 > 0:20:49They'll say, "I'm not that hungry but, when I start eating, I can't stop."
0:20:49 > 0:20:54I'm pretty shocked to discover that my assumption of a lifetime,
0:20:54 > 0:20:58which is that I am the size I am because of my character,
0:20:58 > 0:21:00is nonsense.
0:21:00 > 0:21:03And it seems from what you're saying,
0:21:03 > 0:21:06as if I just have a fortunate hormone set.
0:21:06 > 0:21:08If your hormone levels were different,
0:21:08 > 0:21:10the battle would have been much harder.
0:21:15 > 0:21:18Had I been asked to starve a minute longer,
0:21:18 > 0:21:20I'm not sure I would have managed.
0:21:21 > 0:21:24My hunger hormone was so powerful
0:21:24 > 0:21:27that it actually affected my decision about what
0:21:27 > 0:21:28and how much to eat.
0:21:30 > 0:21:35You actually ate 170 calories more than you would have done
0:21:35 > 0:21:37in comparison to the previous day.
0:21:37 > 0:21:40So not only did you eat the wrong food,
0:21:40 > 0:21:42you also ate more food in total.
0:21:42 > 0:21:46And that's what happens to patients who are overweight.
0:21:46 > 0:21:49They don't feel full after they've had a meal
0:21:49 > 0:21:53and they have to consume more food and the wrong food.
0:21:54 > 0:21:56What it's brought home to me
0:21:56 > 0:22:00is that obesity is not just about will power.
0:22:00 > 0:22:05Its also about our biology, our hormones.
0:22:07 > 0:22:11But that's not the end of the story.
0:22:14 > 0:22:19This epidemic is clearly complex with many other causes.
0:22:19 > 0:22:23And I'm particularly interested in what we can learn from genetics
0:22:23 > 0:22:29because I can see that fat parents often have fat kids.
0:22:29 > 0:22:33And I want to find out if there are clues here
0:22:33 > 0:22:36to help us tackle the problem of obesity.
0:22:45 > 0:22:48There's a really interesting group of people
0:22:48 > 0:22:52who have found themselves unexpectedly at the forefront of this research
0:22:52 > 0:23:01Our similarities - our voices, height, eyes, teeth,
0:23:01 > 0:23:04- noses, dimples... - Dimples, I've got one here.
0:23:04 > 0:23:08And I've got a dimple on this side.
0:23:08 > 0:23:10Nature's own genetic experiment...
0:23:10 > 0:23:14Birth marks on the back of our necks.
0:23:14 > 0:23:19And little freckles and moles on our body in certain places.
0:23:19 > 0:23:22..identical twins.
0:23:22 > 0:23:25- Feet, both flat.- Oh, yes, very.
0:23:30 > 0:23:33Meet Elaine and Liz.
0:23:33 > 0:23:36For most of their lives, they have lived within a mile of each other
0:23:36 > 0:23:38and shared almost everything.
0:23:38 > 0:23:40- Oh, do you remember these pictures? - Yeah.
0:23:40 > 0:23:43Oh, so cute.
0:23:43 > 0:23:46I think we were similar. Very alike.
0:23:46 > 0:23:48Yeah. Very alike there. Definitely.
0:23:48 > 0:23:53We just did not want to have our pictures taken.
0:23:53 > 0:23:54And, like most identical twins,
0:23:54 > 0:23:57as children they were like as peas in a pod.
0:23:59 > 0:24:02And this one is a school picture.
0:24:02 > 0:24:06- They couldn't tell the difference. - Not at all.
0:24:06 > 0:24:11Watching these two it's clear that the relationship between twins is extraordinary.
0:24:11 > 0:24:18There is just a special bond, which you can't explain really.
0:24:18 > 0:24:21- Its just being together...- Together. - Being together.
0:24:21 > 0:24:23- All the time, yeah.- As one.
0:24:23 > 0:24:28- One, but...- But separate. - ..but separate.
0:24:30 > 0:24:33And now Elaine and Liz have found themselves
0:24:33 > 0:24:36right at the heart of obesity research.
0:24:38 > 0:24:41For the last 20 years,
0:24:41 > 0:24:45one man has been studying thousands of identical twins.
0:24:45 > 0:24:50For Professor Tim Spector, twins are a fascinating experiment
0:24:50 > 0:24:55because they can reveal the difference between what we inherit through nature -
0:24:55 > 0:25:02the genes we are born with - or nurture - the environment we experience.
0:25:02 > 0:25:04What is it about twins that helps you
0:25:04 > 0:25:06when you are looking at heritability?
0:25:06 > 0:25:09Twins are the best model in humans of actually working out
0:25:09 > 0:25:15what proportion of ourselves, our traits or diseases are due to genes
0:25:15 > 0:25:20or due to our environment, because you compare identical twins
0:25:20 > 0:25:23and non identical twins, and the two types of twins
0:25:23 > 0:25:25both sharing the same environment,
0:25:25 > 0:25:28so only similarity in one group compared to the other
0:25:28 > 0:25:29must be due to their genes.
0:25:31 > 0:25:35Spector's work with twins convinced him
0:25:35 > 0:25:36that nature - our genes -
0:25:36 > 0:25:42was the most important factor in causing a whole host of traits,
0:25:42 > 0:25:48from freckles to height and, as it turns out, weight.
0:25:54 > 0:25:58But that was until he met identical twins like Elaine and Liz.
0:25:59 > 0:26:02Because, while they share many traits...
0:26:02 > 0:26:05Everything was virtually identical.
0:26:05 > 0:26:10..there's one thing that makes them rather different.
0:26:10 > 0:26:12Say about a stone and a half.
0:26:12 > 0:26:20- I would say at least two and a half stone.- Yeah.- Yeah.- Definitely.
0:26:20 > 0:26:24The sisters are what's known as discordant twins.
0:26:24 > 0:26:29And their very existence flew in the face of all Spector's ideas.
0:26:29 > 0:26:32It was a bit of a shock because I'd spent 15 years of my life
0:26:32 > 0:26:35trying to convince the rest of the world that things are heritable
0:26:35 > 0:26:38and I'm suddenly having to say,
0:26:38 > 0:26:42"Hang on a minute, genes aren't the whole story here, clearly,
0:26:42 > 0:26:48"because these identical clones are behaving very much more differently than we thought they should do."
0:26:48 > 0:26:53The question was, what was making these twins so different in weight?
0:26:53 > 0:26:58They had the same genes, they shared the same environment.
0:26:58 > 0:27:01So, like 99% of identical twins
0:27:01 > 0:27:05they should have been exactly the same weight.
0:27:05 > 0:27:07What level have you got yours on?
0:27:07 > 0:27:10No wonder! You've got yours on one, mine's on three!
0:27:12 > 0:27:16And it turns out Liz and Elaine are not unique.
0:27:40 > 0:27:46Over the last year Tim Spector has discovered another two dozen of these rare discordant twins.
0:27:51 > 0:27:54Hello. I'm Gabriel, lovely to meet you all.
0:27:54 > 0:27:56I'm just bringing some coffees in.
0:27:56 > 0:27:59I'm intrigued to talk to these twins
0:27:59 > 0:28:02to see how their identical genes
0:28:02 > 0:28:04have made them into these genetic paradoxes.
0:28:06 > 0:28:09Maybe you could just tell me a couple of things about
0:28:09 > 0:28:12what is the same and what is different about you.
0:28:12 > 0:28:16Some are still so similar its hard to tell them apart.
0:28:16 > 0:28:18- I'm Debbie.- I'm Mary.
0:28:18 > 0:28:21We very much like the same things, don't we?
0:28:21 > 0:28:22Out taste in clothes is similar.
0:28:22 > 0:28:27Some look different and yet still have that remarkable twin-ness.
0:28:27 > 0:28:29- I'm Angela.- And I'm Irene
0:28:29 > 0:28:32We both have the same kind of silly sense of humour,
0:28:32 > 0:28:36where we can see something and nobody else understands it
0:28:36 > 0:28:39and we just burst into uncontrollable giggles.
0:28:39 > 0:28:42And some seem more like normal sisters than twins.
0:28:42 > 0:28:44- I'm Fiona.- And I'm Jane.
0:28:44 > 0:28:48We get on a lot better now that we are a lot older,
0:28:48 > 0:28:52but unfortunately we live in different parts of the world.
0:29:02 > 0:29:04Today, these twins are in London
0:29:04 > 0:29:08so that Professor Spector can start to work out
0:29:08 > 0:29:10why they are the same but different.
0:29:10 > 0:29:11You guys are special
0:29:11 > 0:29:16because most identical twins are very close in weight.
0:29:16 > 0:29:20You're not. Basically, That's the simple sort of...
0:29:20 > 0:29:22You don't have to be so blunt.
0:29:22 > 0:29:24THEY LAUGH
0:29:24 > 0:29:27In the past we've always said that things like putting on weight
0:29:27 > 0:29:32or your height or whatever are completely determined by your genes,
0:29:32 > 0:29:39and yet you are walking examples of how exactly that's not completely true.
0:29:40 > 0:29:45Spector is putting these discordant twins through a barrage of tests,
0:29:45 > 0:29:49painstakingly looking for clues to how they end up so different.
0:29:51 > 0:29:55He looks for subtle differences in DNA between Liz and Elaine.
0:29:55 > 0:29:59We're going to take this bit of tissue from you
0:29:59 > 0:30:04to see how it differs between you and your sister.
0:30:04 > 0:30:08And he even checks for tiny DNA variations
0:30:08 > 0:30:11in different parts of the same twin.
0:30:13 > 0:30:18So we get your nail clippings. And that's to get extra DNA
0:30:18 > 0:30:24to see if the DNA in your nails is different to that in your blood.
0:30:25 > 0:30:31The answer to the puzzle of why twins with the same genes can be different weights
0:30:31 > 0:30:33seems to be this.
0:30:35 > 0:30:38Spector now believes it's not enough just to have a gene,
0:30:38 > 0:30:42it has to be activated or switched on.
0:30:42 > 0:30:46And the larger twin had her fat genes switched on
0:30:46 > 0:30:49where her thinner sister hadn't.
0:30:49 > 0:30:52Something has switched in them,
0:30:52 > 0:30:56has just switched some of their genes from one position to another
0:30:56 > 0:31:00and that has altered what's happened to their metabolism.
0:31:00 > 0:31:04And, because they are so similar, our idea is that we can track down
0:31:04 > 0:31:06what those chemicals are
0:31:06 > 0:31:10and what those genes are that are changed between the two.
0:31:10 > 0:31:15This new science of how the environment can switch your genes on and off
0:31:15 > 0:31:18is becoming more and more important across modern medicine.
0:31:18 > 0:31:22Its called epigenetics. But the question now is,
0:31:22 > 0:31:26what was causing these genes to be switched on or off?
0:31:29 > 0:31:35Spector has been looking for something that sets one twin's experience apart from the other.
0:31:35 > 0:31:41I maybe got a bit more attention. I had to go to hospital with our mum
0:31:41 > 0:31:45- so I suppose I had stresses early on, didn't I?- Yeah, yeah.
0:31:45 > 0:31:50When do you think the changes occurred or you noticed any differences between you?
0:31:50 > 0:31:55I think the changes happened when she got married and moved away.
0:31:55 > 0:31:59I was married but I had family closer to me
0:31:59 > 0:32:02and she didn't have any family closer to her.
0:32:02 > 0:32:06And I think that's possibly when the change occurred.
0:32:06 > 0:32:08I think that's probably when it did.
0:32:08 > 0:32:11I'm just aware, as we are talking to these ladies,
0:32:11 > 0:32:15that there is so many things that might go on at any one time
0:32:15 > 0:32:18between the lives of two different women.
0:32:18 > 0:32:22How do we know that we are not just randomly selecting factors
0:32:22 > 0:32:25that could be confounded by hundreds of other factors?
0:32:25 > 0:32:27You are absolutely right
0:32:27 > 0:32:33and taking one pair, a snapshot of your life in retrospect,
0:32:33 > 0:32:38which is full of false memories is not a reliable way of doing science.
0:32:38 > 0:32:43So none of what I'm saying will be based on one or two twins stories
0:32:43 > 0:32:45but only by doing this systematically
0:32:45 > 0:32:48across hundreds of twins to see what the common factors are.
0:32:48 > 0:32:54And Spector thinks he's seeing some common factors in all his twins.
0:32:54 > 0:32:57His theory is that stress can create parallel
0:32:57 > 0:32:59but different destinies.
0:32:59 > 0:33:03What was interesting was three out of the five pairs
0:33:03 > 0:33:06did give us a story of how, when they were put under stress,
0:33:06 > 0:33:08they reacted differently.
0:33:08 > 0:33:12For me, what's so exciting about Spector's work,
0:33:12 > 0:33:17is that if he can understand what turns the fat switch on,
0:33:17 > 0:33:19he might find a way to turn it off again.
0:33:19 > 0:33:22To stop obesity in its tracks.
0:33:24 > 0:33:27I think it's very exciting looking into that future.
0:33:27 > 0:33:31We already know many of the genes are responsible for obesity,
0:33:31 > 0:33:33we're going to find hundreds and thousands more,
0:33:33 > 0:33:38but the key to this is how we can change those genes.
0:33:41 > 0:33:45What Professor Spector was saying quite strongly to the twins today
0:33:45 > 0:33:48was, "Even if something has happened
0:33:48 > 0:33:52"to predispose one of you to putting weight on,
0:33:52 > 0:33:57"where the other one has been free of that, this is not set in stone
0:33:57 > 0:34:00"and you could do things, although it might be difficult,
0:34:00 > 0:34:04"which could reverse whatever signal has taken place
0:34:04 > 0:34:06"which has led to one of you being fatter,
0:34:06 > 0:34:08"and one of you being thinner."
0:34:12 > 0:34:18It's strange to think that some small event in your life might change everything.
0:34:18 > 0:34:23That tiny switches in your genes can fine tune how much and when you eat
0:34:23 > 0:34:26and how you body uses that food.
0:34:26 > 0:34:31But it's not the only way that our genes lead to obesity.
0:34:42 > 0:34:44Today, I'm on my way to Southampton
0:34:44 > 0:34:51to find out about an inspiring study based on this new science of epigenetics.
0:34:55 > 0:34:59It's helping us understand what might be making our children fat.
0:35:09 > 0:35:13Professor Keith Godfrey runs this ambitious survey.
0:35:18 > 0:35:23- Professor Godfrey.- Really nice to see you.- Lovely to meet YOU. - Lovely to meet you too.
0:35:23 > 0:35:25His study is ambitious
0:35:25 > 0:35:28because it starts before the child is even conceived.
0:35:30 > 0:35:33I wonder if you can take me right back to the beginning where it all started.
0:35:33 > 0:35:36Well, it all started over 15, 20 years ago
0:35:36 > 0:35:44when we began looking at how a mother's diet before she conceives
0:35:44 > 0:35:47might have lifelong effects on the development
0:35:47 > 0:35:49and the health of her offspring.
0:35:49 > 0:35:51Other surveys have begun during pregnancy
0:35:51 > 0:35:55or have had modest information before conception
0:35:55 > 0:35:58but this is the world's first of its kind.
0:36:01 > 0:36:07These are some of the 12,000 women who joined up over 15 years ago.
0:36:07 > 0:36:12The survey aimed to answer a single, huge question.
0:36:13 > 0:36:18What were all the factors that might make their children obese?
0:36:20 > 0:36:23So, once a week for those...
0:36:23 > 0:36:26Was it influenced by the diet and lifestyle of the parents?
0:36:26 > 0:36:30Five times a week. And once a week for sausages...
0:36:32 > 0:36:35..and no beans.
0:36:37 > 0:36:42Was it shaped by the nine months the baby spent in the womb?
0:36:46 > 0:36:52Or was a child's weight a result of its experiences in the first years of its life?
0:36:52 > 0:36:54OK, don't worry.
0:36:56 > 0:37:00And then after 15 years of searching, they found the answer.
0:37:06 > 0:37:09It sounds like an incredibly work-intensive job,
0:37:09 > 0:37:11and what did it show?
0:37:11 > 0:37:15We've shown that the baby's development in the womb
0:37:15 > 0:37:20influences its risk of obesity six or nine years down the line in childhood.
0:37:20 > 0:37:24It was a completely new cause of obesity.
0:37:24 > 0:37:29It seems that the biggest single factor causing a child to be fat
0:37:29 > 0:37:33was the nine months it spent in its mother's womb.
0:37:35 > 0:37:39Amazingly, they explained something like a quarter of the differences
0:37:39 > 0:37:42between the children in their degree of obesity nine years later.
0:37:44 > 0:37:50This claim that a single cause adds 25% to the risk of childhood obesity
0:37:50 > 0:37:53is enough to make any doctor sit up and listen.
0:37:53 > 0:37:57And in your experience, is that a strong association?
0:37:57 > 0:38:02We've never seen anything as strongly related to the child's obesity before.
0:38:02 > 0:38:06In all the studies that we've performed over the last 20, 25 years,
0:38:06 > 0:38:09never anything quite like this.
0:38:11 > 0:38:16So what was happening in the womb that made this crucial difference?
0:38:19 > 0:38:21Godfrey started to look at the genes
0:38:21 > 0:38:25in the only tissue that links mother to child within the womb itself.
0:38:25 > 0:38:27The umbilical cord.
0:38:31 > 0:38:35So these are the umbilical cords that we've collected
0:38:35 > 0:38:38and over 3,000 women in the Southampton Women's Survey
0:38:38 > 0:38:41have kindly agreed that we could use their cord.
0:38:41 > 0:38:44And how fresh is this specimen?
0:38:44 > 0:38:49So this is a placenta and umbilical cord from earlier today.
0:38:49 > 0:38:55When he analysed the cord he found something unexpected -
0:38:55 > 0:38:58a single switch on a gene called RXRA.
0:38:58 > 0:39:02And it was powerfully linked to childhood obesity.
0:39:04 > 0:39:08And what controlled the setting of this switch was this...
0:39:10 > 0:39:12The mother's diet.
0:39:12 > 0:39:14If the mother is undernourished
0:39:14 > 0:39:17or eats an unbalanced diet in pregnancy,
0:39:17 > 0:39:20the baby thinks that it's going to similarly
0:39:20 > 0:39:22be undernourished after birth.
0:39:22 > 0:39:26Those babies tend to be thin at birth, but in our westernised
0:39:26 > 0:39:30environments where there is not much physical activity
0:39:30 > 0:39:32and high food availability,
0:39:32 > 0:39:37those children are mismatched to that later environment
0:39:37 > 0:39:40such that they progressively put on fat during childhood.
0:39:43 > 0:39:47So the nine months in the womb turn out to be crucial
0:39:47 > 0:39:49to your child's weight.
0:39:49 > 0:39:52And with the right nutrition, it's something we can change.
0:40:04 > 0:40:06I think that this work holds great promise for the future.
0:40:06 > 0:40:11But right now the best health advice hinges on exercise and diet,
0:40:11 > 0:40:13and of course that's right.
0:40:16 > 0:40:19But you just have to look around you to see that its not enough.
0:40:22 > 0:40:25So I'm interested in looking at other ways that scientists
0:40:25 > 0:40:28are thinking about tackling our problem with fat.
0:40:33 > 0:40:36I'm on my way to meet a woman who is about to undergo what
0:40:36 > 0:40:40I think is a fairly extreme treatment for obesity.
0:40:44 > 0:40:48But it's a treatment that might have much wider implications.
0:40:50 > 0:40:53- Hi.- Hi, I'm Gabriel. - I'm Marilyn, come in.- Thank you.
0:40:53 > 0:40:55- Thanks for having me. - That's all right. Come through.
0:40:57 > 0:41:00Marilyn Walsh is a mum who lives in South London.
0:41:02 > 0:41:04She weighs over 21 stone.
0:41:06 > 0:41:10- Four years old I was there. - Let's have a look, lovely.
0:41:10 > 0:41:14Yes, but not, not thin, look at the chubby cheeks.
0:41:14 > 0:41:16What have we got here?
0:41:16 > 0:41:19I'd be about 9, and you can see the weight already.
0:41:19 > 0:41:22- Yeah?- Yeah.
0:41:22 > 0:41:24Like most overweight adults,
0:41:24 > 0:41:28Marilyn has found that diets have consistently failed.
0:41:28 > 0:41:30And is this the stage that you were telling me about,
0:41:30 > 0:41:33where your mum was already putting you on diets?
0:41:33 > 0:41:36Yeah already, mum was already trying with the diets, already, you know,
0:41:36 > 0:41:40carrot sticks, cucumber sticks at break time.
0:41:40 > 0:41:43What these photos are sort of painting a picture of
0:41:43 > 0:41:46in a way is the sort of lifetime of being overweight.
0:41:46 > 0:41:49Yes, constantly having a weight problem, you know, which it is,
0:41:49 > 0:41:51it's a... it is a weight problem.
0:41:51 > 0:41:55Why can't you just lose weight, like why can't you just
0:41:55 > 0:41:59not eat the things that are making you put the weight on?
0:41:59 > 0:42:02It would be a bit like saying why can't an alcoholic
0:42:02 > 0:42:06stop drinking. Why can't a smoker stop smoking, it's exactly
0:42:06 > 0:42:11the same answer you'd ask them. There isn't, there isn't an answer,
0:42:11 > 0:42:15it's... Something that's been with me all my life.
0:42:15 > 0:42:18And you just feel hungry all the time?
0:42:18 > 0:42:22I'm always hungry and always wanting food.
0:42:22 > 0:42:28Worst picture of all. Biggest, I think, I ever was.
0:42:30 > 0:42:32At the moment Marilyn is healthy,
0:42:32 > 0:42:35but she know from her family the sort of problems that may await her.
0:42:37 > 0:42:43My uncle, my dad's brother, he was I think about 35 stone,
0:42:43 > 0:42:46suffered with weight throughout his whole life -
0:42:46 > 0:42:49leg problems, stopped walking.
0:42:49 > 0:42:52- Couldn't go anywhere, couldn't get in a chair so he had to sit on the floor.- Wow.
0:42:52 > 0:42:55He developed diabetes through it and lots of other problems.
0:42:55 > 0:42:58And he did die because of his weight.
0:43:01 > 0:43:03Unless something radical is done for her,
0:43:03 > 0:43:06Marilyn is likely to face a future
0:43:06 > 0:43:08of ill health and expensive treatments.
0:43:10 > 0:43:13But Marilyn is now part of an experiment that might shed light
0:43:13 > 0:43:18on how we might be able to change appetite and fatness forever.
0:43:26 > 0:43:31I've come back to Imperial to meet up again with Dr Carel Le Roux.
0:43:31 > 0:43:35Having convinced me that hormones shape our appetite,
0:43:35 > 0:43:38he now believes that one particular kind of surgery
0:43:38 > 0:43:42can fundamentally change the levels of these hormones.
0:43:44 > 0:43:48Surgery on the stomach - what's called a gastric bypass.
0:43:50 > 0:43:54Can you explain to me the mechanics of gastric bypass surgery?
0:43:54 > 0:43:56So let me explain it like this.
0:43:56 > 0:44:00That's the oesophagus or the gullet, this is the stomach
0:44:00 > 0:44:03and this is the small bowel and this is the large bowel.
0:44:03 > 0:44:06What the surgeons do is they cut the stomach
0:44:06 > 0:44:08and they cut the small bowel.
0:44:08 > 0:44:11So you are now left with you're oesophagus normal,
0:44:11 > 0:44:14you have now a small stomach, so your stomach
0:44:14 > 0:44:18goes from the size of your two fists into the size of your thumb.
0:44:18 > 0:44:21The rest of the stomach remains in place
0:44:21 > 0:44:26and the first 50cms of your small bowel and that's why
0:44:26 > 0:44:29it's called the stomach bypass because we take the bottom
0:44:29 > 0:44:33bit of the small bowel and connect it to the small stomach
0:44:33 > 0:44:37and now food is bypassing the stomach
0:44:37 > 0:44:40and the first part of the small bowel.
0:44:40 > 0:44:44Reducing the size of the stomach obviously limits how much
0:44:44 > 0:44:48a person can eat. But it has a more unexpected effect too.
0:44:48 > 0:44:51It also changes the patient's behaviour.
0:44:51 > 0:44:54So what you're saying is that in this particular operation actually
0:44:54 > 0:44:57seems to affect someone's motivation to eat?
0:44:57 > 0:44:59That's right,
0:44:59 > 0:45:02the patients come to us in clinic and say,
0:45:02 > 0:45:05"Doctor where did the surgeon do the operation,
0:45:05 > 0:45:08"did they operate on my tummy or did they
0:45:08 > 0:45:11"operate on my head because I don't feel hungry any more,
0:45:11 > 0:45:15"when I do eat I feel full and all these changes
0:45:15 > 0:45:16"have really happened in my head."
0:45:21 > 0:45:25This is a really intriguing piece of research,
0:45:25 > 0:45:28because it suggests a way that we might be able to alter
0:45:28 > 0:45:31one of the most fundamental drives - appetite.
0:45:31 > 0:45:36It's this operation that Marilyn has been selected for.
0:45:36 > 0:45:39Her doctors at Kings College Hospital believe it's now the only
0:45:39 > 0:45:43chance to save her from a future of debilitating illness.
0:45:45 > 0:45:46- Hi Marilyn.- Hello.
0:45:46 > 0:45:50- How are you today? - I'm Fine thank you.
0:45:50 > 0:45:52Good. How are you feeling?
0:45:52 > 0:45:54- Excited, ready and waiting.- Good.
0:45:54 > 0:45:57Any concerns at all or just looking forward to it
0:45:57 > 0:46:00- and everything it means? - Just looking forward to the new journey.
0:46:00 > 0:46:01Good. Right,
0:46:01 > 0:46:03good luck with it, I'm sure you won't need it.
0:46:05 > 0:46:09The surgeon, Mr Ameet Patel has allowed me to watch the procedure.
0:46:11 > 0:46:13It's a controversial operation,
0:46:13 > 0:46:16sometimes seen as an expensive quick fix.
0:46:18 > 0:46:21And until I made this film, it was view that I shared.
0:46:21 > 0:46:25When I was here ten years ago working as a junior surgeon,
0:46:25 > 0:46:28I have to confess I used to think it was a very extreme measure
0:46:28 > 0:46:30for patients to take just because they were overweight.
0:46:32 > 0:46:35In the old days we'd make a cut here and here,
0:46:35 > 0:46:39we'd get inside, do the operation, it would be all open surgery.
0:46:39 > 0:46:42Actually what we can do as an open operation we're doing as
0:46:42 > 0:46:45a keyhole now. And the recovery's much better and quicker.
0:46:45 > 0:46:48And I suppose the thing I see now which I didn't see then is that for
0:46:48 > 0:46:53a lot of patients this is the end of a lot of things that they've tried.
0:46:53 > 0:46:57Exactly, they want something to change their lives...
0:46:57 > 0:47:01and that's what it does, it actually changes your life...
0:47:07 > 0:47:09As its done by keyhole surgery
0:47:09 > 0:47:14Mr Patel starts by making a series of small incisions on the abdomen.
0:47:17 > 0:47:18And as you can see
0:47:18 > 0:47:21we're going through the layers...
0:47:21 > 0:47:23And that's fat that we are looking at the on the camera isn't it?
0:47:23 > 0:47:30Yes. We're now going through the...muscle layers.
0:47:30 > 0:47:32And here we've got to be a little bit careful as we
0:47:32 > 0:47:36get into the abdominal cavity without injuring anything.
0:47:37 > 0:47:39Let's put the CO2 on for me.
0:47:41 > 0:47:44So some gas is being what we call insubflated through
0:47:44 > 0:47:47the instrument here and what that does is gives
0:47:47 > 0:47:51a kind of expanded sort of tented view of the anatomy he needs to see.
0:47:53 > 0:47:57Its an operation that carries rare but serious risks.
0:47:58 > 0:48:01There is the stomach.
0:48:01 > 0:48:05It's quite a big stomach, you can see it all the way round.
0:48:05 > 0:48:06This is all fat here?
0:48:08 > 0:48:10This is all fat.
0:48:10 > 0:48:14Resting on her stomach is a large slab of visceral fat, the fat
0:48:14 > 0:48:16that in excess can poison our organs
0:48:16 > 0:48:19causing diabetes and other diseases...
0:48:22 > 0:48:24Before Mr Patel can connect
0:48:24 > 0:48:27the small bowel to the bottom of the stomach,
0:48:27 > 0:48:31what he needs to do is create the pouch which will be the new stomach.
0:48:31 > 0:48:35Using a tool which both staples and cuts,
0:48:35 > 0:48:37he creates the new smaller stomach.
0:48:41 > 0:48:44So that's the new stomach there. And old stomach down here.
0:48:44 > 0:48:46Old stomach on that side.
0:48:49 > 0:48:52The operation usually results in the patient's losing
0:48:52 > 0:48:53a third of their weight
0:48:53 > 0:48:56and keeping it off for at least the next twenty years.
0:49:05 > 0:49:06But if Dr Le Roux is right,
0:49:06 > 0:49:10Marilyn won't lose weight just because of her smaller stomach.
0:49:10 > 0:49:14It'll be because the operation has changed the way she thinks.
0:49:31 > 0:49:33It's six weeks after the operation.
0:49:35 > 0:49:37I really want to see what's happened to Marilyn.
0:49:38 > 0:49:40Hi!
0:49:42 > 0:49:46So Marilyn, what are you wearing?
0:49:46 > 0:49:49These are my trousers from before the operation.
0:49:49 > 0:49:55These are you pre-op trousers. Look at that! Wow!
0:49:55 > 0:49:58That's amazing, that really is amazing.
0:49:59 > 0:50:01But what I was really interested in
0:50:01 > 0:50:04was how the operation had changed her appetite.
0:50:07 > 0:50:10Now perhaps after a couple of table spoons
0:50:10 > 0:50:12and I get a heavy feeling in my stomach which
0:50:12 > 0:50:16I presume is what you would class as, I am full up now and I'll stop.
0:50:16 > 0:50:20I can't eat any more. I never had that before.
0:50:20 > 0:50:22I just want to stop and ask you a little bit
0:50:22 > 0:50:24about the sorts of foods that you used
0:50:24 > 0:50:26to choose by preference,
0:50:26 > 0:50:28and the sorts that you would choose now?
0:50:28 > 0:50:33I don't like the sweet or the fatty, the fatty isn't appealing anymore.
0:50:33 > 0:50:38So the two tastes that drove you before, which were fatty
0:50:38 > 0:50:40and sweet you now don't have any interest in?
0:50:40 > 0:50:44No, but the sweet, when I tasted that hot chocolate last week
0:50:44 > 0:50:46and the sweet it turned me, it was awful.
0:50:48 > 0:50:51And the fat on the roof of your mouth, that was horrible,
0:50:51 > 0:50:54trying to get rid of that takes a long time.
0:50:58 > 0:51:02For Marilyn, I hope this is the beginning of much healthier
0:51:02 > 0:51:06relationship with food, one that will finally be sustained.
0:51:11 > 0:51:14It's clear that Marilyn's gastric bypass
0:51:14 > 0:51:15hasn't just reduced her appetite,
0:51:15 > 0:51:20It's completely altered her relationship with food.
0:51:20 > 0:51:24And doctors are discovering this result again and again.
0:51:24 > 0:51:28I really want to know how this works.
0:51:28 > 0:51:30How is it possible that an operation
0:51:30 > 0:51:33conducted on someone's stomach
0:51:33 > 0:51:37can be so radically altering how their brain works?
0:51:43 > 0:51:45I want to meet one of Dr le Roux's colleagues who is studying
0:51:45 > 0:51:51how gastric bypass surgery actually changes patients' brains.
0:51:56 > 0:52:01Dr Samantha Scholtz is a consultant psychiatrist at Imperial College.
0:52:13 > 0:52:14So what got you into obesity?
0:52:14 > 0:52:17Well as a psychiatrist I'm interested in human behaviour,
0:52:17 > 0:52:21particularly the kind of behaviour which drives a lot of
0:52:21 > 0:52:23what we see every day.
0:52:23 > 0:52:24And if you think about it,
0:52:24 > 0:52:26there are not a lot of stronger drivers
0:52:26 > 0:52:30than food and seeking out food.
0:52:30 > 0:52:34What's your specific line of enquiry in obesity?
0:52:34 > 0:52:36I was interested in how obese people's brains
0:52:36 > 0:52:39differed from people of normal weight's brains.
0:52:39 > 0:52:42And what kind of tools were you able to use
0:52:42 > 0:52:45for the science of your investigation?
0:52:45 > 0:52:48When I first started psychiatry we didn't have a lot of tools
0:52:48 > 0:52:50to see how the brain actually functions
0:52:50 > 0:52:53and as time has gone on
0:52:53 > 0:52:59things like functional MRI have become much more valuable.
0:53:02 > 0:53:06Dr Scholtz is now using new MRI techniques
0:53:06 > 0:53:08to compare obese patient's brains
0:53:08 > 0:53:10before and after gastric bypass Surgery.
0:53:14 > 0:53:16And today I am part of her experiment.
0:53:22 > 0:53:25First she shows me a selection of high fat foods.
0:53:30 > 0:53:32And the MRI scans my brain for activity,
0:53:32 > 0:53:36indicating my subconscious desire for these foods.
0:53:43 > 0:53:46Then I'm shown healthy foods. And the MRI measures again.
0:53:51 > 0:53:55It's actually quite unnerving because with this machine,
0:53:55 > 0:53:57you can't hide your feelings.
0:54:05 > 0:54:08Later she shows me what she's found.
0:54:08 > 0:54:10So you have some MRIs to show me.
0:54:11 > 0:54:14This is the activity in your brain or the areas that are lit up,
0:54:14 > 0:54:17the red areas, the areas that were more active when you were
0:54:17 > 0:54:21looking at the pictures of high calorie appetizing food.
0:54:21 > 0:54:26High fat food was clearly having very little effect on my brain.
0:54:26 > 0:54:31This is a representative MRI for someone of normal weight?
0:54:31 > 0:54:35Yes, fairly representative of that kind of picture.
0:54:35 > 0:54:37On the other hand, if we look at someone
0:54:37 > 0:54:41who is just about to have gastric bypass surgery
0:54:41 > 0:54:43you can see quite a big difference here.
0:54:43 > 0:54:46So this is the obese or overweight person's scan?
0:54:46 > 0:54:49Yes this is activation in her brain looking at exactly the same
0:54:49 > 0:54:51- pictures that you were.- Wow.
0:54:51 > 0:54:54- You can see a big difference. - That's huge isn't it?
0:54:54 > 0:54:57So you're seeing a lot of activation in areas which
0:54:57 > 0:54:59we know are associated with rewards such as the orbital frontal cortex
0:54:59 > 0:55:03but also area like the ventral striata and amygdala
0:55:03 > 0:55:07which we associate with addiction and an emotional response to food.
0:55:07 > 0:55:14The blue was revealing the obese brain's deep desire for fatty food.
0:55:14 > 0:55:16So the green is the same lady
0:55:16 > 0:55:20after she has had gastric bypass surgery about five months later.
0:55:20 > 0:55:26The patient's brain response to fatty food has now totally changed.
0:55:26 > 0:55:29So it's really a striking difference isn't it?
0:55:29 > 0:55:33Yeah, I mean if we were to compare this person's brain after
0:55:33 > 0:55:36surgery to your brain, so someone who is of normal weight,
0:55:36 > 0:55:39we can see not a lot of difference there.
0:55:44 > 0:55:46I'm really impressed.
0:55:46 > 0:55:49The operation seems somehow to have pressed
0:55:49 > 0:55:51the reset button in the brain.
0:55:55 > 0:55:59I mean, this scan looks like you have changed the brain
0:55:59 > 0:56:04of a fat person into the brain of a normal person.
0:56:04 > 0:56:08In effect with bypass surgery is changing someone's brain
0:56:08 > 0:56:11fundamentally so their reaction to seeing high-calorie food
0:56:11 > 0:56:15is different and that would ultimately drive their choices
0:56:15 > 0:56:20of food so that they stop having that battle with food that they
0:56:20 > 0:56:22had before and are more like someone like yourself
0:56:22 > 0:56:24who doesn't have that same battle with food.
0:56:28 > 0:56:32Of course, surgery is not the answer for everyone.
0:56:32 > 0:56:35But if Dr Le Roux can find another way to produce the effects
0:56:35 > 0:56:41of the operation then he's found a powerful new weapon against obesity
0:56:41 > 0:56:44The next point is maybe we can use devices -
0:56:44 > 0:56:50we can put things into the bowel that can mimic the operation.
0:56:50 > 0:56:54Or we can use injections or pills that actually will
0:56:54 > 0:56:55do what the operations are achieving.
0:56:57 > 0:57:03Now if we do that, that opens up the whole science of obesity.
0:57:03 > 0:57:07And this will allow us in five years, ten years from now,
0:57:07 > 0:57:13to have treatments that will have incredible benefits to the masses.
0:57:20 > 0:57:24Obesity is clearly an incredibly complex issue
0:57:24 > 0:57:29And one on which it is all too easy to take the moral high ground.
0:57:33 > 0:57:34It's linked to our genes...
0:57:34 > 0:57:36our hormones...
0:57:36 > 0:57:38even to our brains.
0:57:41 > 0:57:43So merely saying that it's a question of willpower
0:57:43 > 0:57:44just isn't good enough.
0:57:49 > 0:57:53And I've started to see that a new set of answers is emerging
0:57:53 > 0:57:56which might help us to begin to defeat, what, to me,
0:57:56 > 0:58:00is one of the defining epidemics of our age.
0:58:18 > 0:58:21Subtitles by Red Bee Media Ltd.