Sugar v Fat Horizon


Sugar v Fat

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We're doctors, brothers, and twins, and we both love to eat,

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but which is worse for us - fat or sugar?

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It's the hottest question in nutrition right now,

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with sugar in particular being targeted as public enemy no 1.

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Sugar is the thing that's making you specifically sick.

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We're going to find out if too much sugar or too much fat

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can make you sick or pile on the pounds.

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You're a quarter fat!

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One of us is going on an extreme high fat diet.

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This is Tiger. Tiger is basically on my diet.

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The other, on an extreme high sugar one.

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None of these foods have any fat, do they?

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It's a high-carb, sugary diet.

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During these month-long diets, we'll be testing how our minds...

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I bought loads of them!

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..and our bodies cope with just eating fat or sugar.

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I feel like I'm out of juice.

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And what we discover is really surprising and really unsettling.

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It overturns my entire way of how I think about my body.

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I'm not well!

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But after meeting this scientist

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and some cheesecake-eating rats, we found that the latest

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scientific research changed what we thought we knew about fat and sugar.

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Total opposite of I think what we would expect,

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what most doctors would expect,

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what most people in the street would expect.

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And it has the potential to do the same for you.

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I'm Dr Chris van Tulleken,

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and I'm a specialist in infectious disease.

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Here in Britain, fat's traditionally been seen as the major problem.

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When I trained as a doctor it was clear that fat was the enemy

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because it raises your cholesterol

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and it blocks up your arteries, causing strokes and heart attacks.

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Over in America, it's sugar that's under attack.

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I'm Dr Xand van Tulleken and my speciality is in tropical medicine.

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Now, in the States, sugar isn't just regarded as unhealthy -

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some people are even calling it toxic.

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So, who's right?

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It's a question that's fascinated us as doctors, and by a quirk

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of birth, we have a head start in getting to grips with it.

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Chris and I are identical twins,

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which means we're genetically the same,

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so we're in a really nice position to do an experiment on each other.

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Now, I live in New York so I get constant messages

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in the media about how fat is good for you and sugar is

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really the enemy, so I'm going to go on a high fat, low sugar diet.

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And although in Britain we do get this message,

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it's not as pervasive, and I'm convinced if I go on a low fat,

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high sugar diet, I will stay healthy.

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So who's right? The Americans who think that sugar is really toxic?

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Or the British, who think that fat is the deadly ingredient?

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We're going on extreme diets based on the sort of techniques used

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in scientific research,

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although we are a rather unscientific sample of just two.

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We want to know what they do to your weight and how

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they affect lifestyle diseases like heart problems and diabetes.

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Nutritionist Amanda Ursell is on hand to make sure

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we get it right, and that it's edible.

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If we kick off with Chris.

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-Chris, you are on the high sugar diet.

-Yeah. I can see that.

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People tend to think of sugar as this,

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the white stuff in the bowl, but actually all of this food

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ultimately gets broken down into blood sugar.

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So, you are allowed bread and bagels, pasta, rice,

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potatoes, any description of breakfast cereals.

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-And what's this?

-That's, er, a fizzy drink.

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And you can have some fruit and veg.

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Well, you can have unlimited fruit and veg.

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And they've all got sugar and none of these... these foods have any fat, do they?

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It's designed to be very low fat and it's a high carb sugary diet,

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and that's what you can live on for the next month.

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For Xand, this is your bit here.

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Basically, you can have cheese, you can have meat, you can

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have steak, you can have burgers, it's chicken with the skin on,

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you can have double cream in your coffee, you can have mayonnaise...

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-The kind of thing you would do.

-But you're not allowed any fruit,

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and you're not allowed very much of this veggie stuff at all.

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My problem is that I'm not going to have a poo for a month, am I?

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Well, there are disadvantages.

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Firstly, your girlfriend doesn't want to kiss you

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because you have bad breath.

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Constipation, yes, you're right.

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I'm getting almost no fibre in any of this, am I?

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Very limited fibre.

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I think I'm going to be craving a bowl of fresh greens

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by the end of a few days.

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I'm sure you are.

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What do you think, Xand? I mean, I feel like you got the better deal.

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It's difficult cos I'm going to have bad breath

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-and I'm not going to poo.

-Mm.

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But I get to have bacon and eggs for breakfast.

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Just to be absolutely clear, we can both eat as much as we want

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of the things on our bit of the table?

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Yeah. That's what we want you to do.

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These diaries are going to be quite hard to stick to,

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so we're going to film them.

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We're going to make video diaries using our phones.

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So at least for the duration of the video diaries, Xand won't be able

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to be shovelling carbohydrate into his mouth.

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Just woken up, and what I feel like is a massive stack of pancakes,

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with maple syrup.

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The point is, if I have to tell into my phone every day

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what the experience is, I can't lie.

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-Keeps us honest.

-Yeah. That's the plan.

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What we're going to do now is sample how much oxygen your body consumes.

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Food is, of course, the fuel that powers our bodies.

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But just how it does that is subject to complex metabolic processes.

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Dr Richard MacKenzie studies how these processes influence diseases like diabetes.

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It's long been thought that eating too much fat can make us fatter,

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and that saturated fat can raise our cholesterol.

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High amounts of cholesterol are quite bad for us.

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They block our arteries and that blocks blood supply

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to the brain and heart,

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so that's quite dangerous.

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Eating or drinking sugar, on the other hand, releases insulin,

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a hormone that regulates our blood sugar.

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Eating too much sugar can make us fat,

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and could potentially lead to diabetes.

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We're going to be checking to see if our cholesterol and insulin levels

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go up or down over the next month.

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What's nice about this experiment, it's not a big experiment,

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but we're well-controlled,

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-and so we really should get a robust answer from this.

-Yeah.

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OK, gentlemen, what I need you to do is to pop behind the curtains

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and strip down into your boxer shorts, please.

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We're expecting these diets to have an impact on our bodies.

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And one thing we're focusing on are changes not to just to fat,

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but also to muscle.

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Shifting fat is good, but losing muscle isn't healthy.

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You do look very different to when I last saw you,

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and I must look different as well.

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Yeah, you've got a little bit fatter.

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The first time in a few years we look a bit like twins.

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OK, gents, we'll just go for the bod pod now,

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I can see you're both a little cold.

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It's freezing in here.

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I feel a bit underdressed.

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MACHINE: It is important to remove any jewellery,

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shoes or eyeglasses before weighing.

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Here we go.

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Enter the bod pod, then close the door to begin test.

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This machine measures the ratio of fat to muscle.

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So Richard, we know that being fat isn't good for you, but why do

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we need all this fancy equipment to measure it so precisely?

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It's to help improve our understanding of exactly what

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increased body fat is doing, and we know that it's

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linked to a number of diseases that reduce our life expectancy.

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So things like cancer, diabetes, heart disease, strokes,

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hypertension, to name just a few,

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all are related to an increase in body fat.

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-It's the same noise as the Batmobile canopy coming out.

-Mm.

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Close the door to begin test.

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And now we freeze him and send him into outer space.

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Yeah, that's the plan.

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So we've got the results from the body composition test.

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So can we try and guess? Before you tell us, can we try and guess?

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-Please do.

-I think I'm 25%.

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I feel like someone who almost a quarter of their body is fat,

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that's how I feel.

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You're pretty much spot-on, you're 26.7% body fat.

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Spot-on, but slightly more than spot-on.

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Good news for Chris is, he's 22% body fat.

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Oh, so we're pretty similar. Oh, that's quite good, actually.

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I mean I think, you know, there is going...you know, he...

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-So am I overweight?

-Um, well, we'd have to look at your BMI for that.

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Don't pull the punch. Yes.

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-A little.

-You're a quarter fat!

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-Look, Richard's being so nice about it!

-"A little,

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"I mean, we couldn't - we'd need to look at the chart."

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All right, all right, I get the message, I get the message.

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-And he's OK, is he?

-A fraction over,

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um, but certainly on the healthier side of 20, 22.6%.

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I'm letting you down.

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You're letting your genes down.

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Yeah, sorry about that.

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I'm eating a little piece of turkey rolled up in a piece of cheese.

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I'm eating everything with my fingers now!

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We're two weeks into the diets, and we now want to start

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measuring how fat and sugar are affecting our bodies.

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And the place we want to start is with our brains.

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Everything goes through your brain, every decision you make,

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every action you take.

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So it'd be pretty important to know

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if cutting out fat or sugar affected how well your brain worked.

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At some point, we've all felt the pressure of mental stress

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and tension, but how does what you eat effect how you deal with it?

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And there are fewer more cognitively demanding environments

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than a city day trading room.

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So, we're going to put our diets to an extreme mental test

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by becoming stock traders for the day.

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Chris, on his high sugar diet, is in London,

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and I'm on my high fat diet in New York.

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So Chris, do you have any sense that you're going to be any good at this?

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It is like the Matrix.

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I'm looking at a financial horror show, this is just a mess.

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I mean, no wonder the economy collapsed.

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How could anyone understand?

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OK, so that we have a bit of help, JJ is going to give us a hand, OK?

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-JJ.

-Hey, Chris, you've got to have a better attitude going in, buddy,

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you're a smart guy, it's not that hard.

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X axis, Y axis, it's...

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It's buy high, sell low, yeah?

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Er, buy low, sell high.

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The other way.

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OK, trade, and right there you see a bid.

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After a quick lesson with JJ, we're let loose on US-based

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TD Ameritrade's paper money application, and we've got

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100,000 dollars of pretend money to play with.

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Yeah.

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It was a pleasure, guys. Chris, good luck. Xand, good luck.

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May the best twin win.

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-Right.

-And thank you very much, fellas.

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I can buy a bit of that.

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I'm going to buy some more companies now.

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I'm into it now.

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Ten of oil, light sweet crude.

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If the oil comes up then I will have made a bunch of money.

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OK, so now the pressure's on cos I've spent all my money.

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'Watching closely in the background is Professor Robin Kanarek.

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'She studies the effects of diet on cognition,

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'and she thinks I might be in for a hard time.'

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Don't know what any of this means.

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This is an extraordinarily difficult task because there's many

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different aspects of cognition that have to be involved.

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He has to first pay attention, then he has to remember what he's done.

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What I can't remember is how many I bought and how many I sold.

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And then he has to make decisions,

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what we call executive processing,

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he has to decide whether to buy or sell.

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So he's got multiple things that are going on at the same time.

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Oh, no, I bought loads of them.

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See, now I've got negative money,

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and no way of getting back out of the hole.

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My problem is that being on a high fat diet could limit

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the fuel for my brain.

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I'm really stuck on this now.

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Glucose is the primary fuel of the brain

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and the best fuel for the brain.

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Since he's been on a low carbohydrate diet,

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almost eating no carbohydrates,

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his stores of glucose in the body are going to be very low.

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Um, and therefore I think as time goes on, he may be having

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more difficulty with the task.

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And I'm short of glucose on my extreme high fat diet.

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But the body has a back-up plan.

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It can turn fat into energy compounds called ketones,

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but they aren't as efficient.

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In normal everyday life, that's not a problem.

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But when you need to think really hard, it can be.

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I've got the initials in head and I can't remember what they stand for.

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Then I've got to try and remember something about the companies.

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The professor's research indicates that without enough carbohydrate

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in your diet, your memory can be significantly compromised.

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There are certain parts of the brain that use carbohydrates, particularly for memory,

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and if they're aren't getting enough glucose, then they can not function properly.

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Getting Exile at 97 dollars 29.

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Over in London, things are markedly different.

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Chris on his high sugar diet is more alert, has more energy,

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and has a significantly better memory.

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When I'm thinking hard I can really feel inside my head

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brainwork going on, and this is very brain-heavy,

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it's remembering loads of numbers, remembering loads of initials,

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and learning a whole new language of bidding and asking.

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So this screen means everything's going green

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so everything's going up, so you just have to hope that continues.

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I think I might be doing OK on my high sugar diet,

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because the brain consumes 60% of the sugars in your blood.

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For people who are on diets that have complex carbohydrates,

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er, whole grains, fruits and vegetables,

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there's a lot of studies that show at least on a short-term basis

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that having a high carbohydrate diet will facilitate memory.

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It's such fun.

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I can see why these guys get really into it.

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It's the end of the test, so who won?

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I can't remember what I wanted to do,

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let alone the numbers and letters I needed to do it.

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I'm not cut out for this.

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Maybe Chris'll have done better.

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So Xand made...Xand made essentially 300 dollars profit

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and I've made over 800 dollars profit.

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So I absolutely thrashed him,

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and I tell you what, I could not have done that if I'd been

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feeling hungry or wanting something I couldn't have, like some sugar,

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and a big carb breakfast is what meant I could do that.

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Scientists are now beginning to understand how certain parts

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of our memory are affected by carbohydrates.

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On my high sugar diet I'm eating all kinds of carbs from starches

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to grains, vegetables to fruit.

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But no matter what form the carbohydrates come in,

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it's all broken down in my gut

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into single sugar molecules, like fructose or glucose.

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And the effect of these molecules on our bodies

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that's at the core of why some scientists,

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particularly in America, argue that sugar's bad for you.

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So Xand's in San Francisco,

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to meet one of the researchers who's led the charge against sugar.

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He's seeing Dr Robert Lustig, who's convinced that the way fructose

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and glucose work in our bodies leads to all kinds of health problems.

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Robert, do you want to pause in the doughnut store

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-and get a bucket full?

-I...I... We'll talk about it later.

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For him, glucose and fructose are dangerous for different reasons.

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First of all, fructose.

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Turns out, only the liver can metabolise fructose,

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and you have a limit to how much you can metabolise, just like any drug.

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You have a threshold.

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If you go over that threshold, your liver has no choice

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but to take that extra energy that's been delivered to it

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and turn it into liver fat,

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because that's the way the way the liver gets rid of extra energy.

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So you drink a bottle of soda, some of it you can metabolise,

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but the rest of it has to become liver fat?

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That's right.

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And that liver fat can have damaging consequences for your health.

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It can make you more liable to heart disease, strokes, or diabetes.

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But according to Dr Lustig, that's just half the problem with sugar.

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The glucose molecule activates insulin,

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the hormone that controls blood sugar.

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But Lustig believes insulin does a whole lot more.

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Insulin shunts sugar to fat. The more insulin, the more fat.

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Well, guess what? The more insulin, the more disease, too.

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-OK.

-And insulin is really the lynchpin in this whole story,

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because whether you gain weight and whether you get sick

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has everything to do with what your insulin does,

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and if you can keep your insulin level down,

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then you won't drive energy into fat,

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you have a chance to lose weight,

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you won't be making your arteries thicker,

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you have a chance for your blood pressure to come down,

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and this is what we've seen,

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is, "it's the insulin, stupid."

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It's known as the hormone hypothesis,

0:20:200:20:23

because fat cells respond to the release of insulin by holding

0:20:230:20:27

onto fat, and making more of it.

0:20:270:20:30

In general, the studies that support the theory about fructose

0:20:390:20:42

only looked at diets with unrealistically high levels of fructose.

0:20:420:20:46

Much more than the average person consumes.

0:20:470:20:50

So I'm not yet convinced about fructose.

0:20:510:20:54

And as for the insulin hypothesis,

0:20:560:20:58

the comprehensive study hasn't been done yet.

0:20:580:21:01

So like most scientists in Britain,

0:21:010:21:04

I'm pretty sceptical about these claims.

0:21:040:21:06

I'm three weeks into my high fat diet

0:21:110:21:13

and I'm really starting to miss carbohydrates.

0:21:130:21:16

I've got on the plane very early,

0:21:170:21:21

which means I can try and eat my burger quickly

0:21:210:21:24

before anyone sits next to me.

0:21:240:21:25

It's really hard not to eat the French fries.

0:21:250:21:28

So I'm all done.

0:21:330:21:35

This is what remains.

0:21:350:21:37

But even though I couldn't eat the carbs,

0:21:440:21:46

I wasn't ravenous after my meal.

0:21:460:21:48

What I really want to know is

0:21:490:21:51

if that has anything to do with the amount of fat in my diet?

0:21:510:21:54

To try and understand what's happening,

0:22:030:22:05

Xand has to fly back to Britain...

0:22:050:22:07

Right, boys. We want you to do something...

0:22:090:22:12

..where Amanda Ursell has set up what she calls

0:22:120:22:15

a hunger experiment.

0:22:150:22:17

We start the day eating the same amount of calories for breakfast.

0:22:230:22:27

Xand has a plateful of fat calories, but mine is chock full of sugar.

0:22:330:22:37

Three hours later, we're offered lunch.

0:22:400:22:44

And this is where it gets really interesting.

0:22:460:22:49

Because now, Amanda can test whether or not eating fat or sugar

0:22:500:22:55

has had any effect on how hungry we were.

0:22:550:22:59

Well, I'm jotting down what you're having,

0:22:590:23:01

so I'm going to count all the calories that you're going

0:23:010:23:03

to have, so I know exactly what's on the plate, so, there we are.

0:23:030:23:06

So will we eat the same number of calories like we did at breakfast?

0:23:060:23:10

-I'm going to start with this soup.

-OK, the soup.

0:23:100:23:14

-Come on, come on.

-Go on, then - off you go.

0:23:140:23:18

Start eating. I'm going to work all this out for you.

0:23:180:23:22

We both start hungry, but that doesn't last for long.

0:23:220:23:27

Do you think I'm going to be able to eat all that?

0:23:310:23:33

-No, no.

-Delicious though this all looks, I'm not really enjoying it.

0:23:330:23:37

All right, what else can I have?

0:23:390:23:41

We've got some pasta.

0:23:410:23:42

-Pasta.

-Yeah.

0:23:420:23:44

But is how hungry we feel just down to the calories we consume?

0:23:440:23:48

It's like I just don't want any more of that.

0:23:520:23:55

My brain has just said, "No, that's it, that's all you need."

0:23:550:23:57

-Can I take that? I need to measure what you've left.

-Absolutely.

0:23:570:24:01

Or could it be the macronutrients in the meals, fat or sugar,

0:24:020:24:07

that are governing how hungry we feel?

0:24:070:24:09

-On this diet I can still eat to shame.

-Really?

0:24:100:24:14

To the moment at which I hate myself more than I want to keep eating.

0:24:140:24:18

Can you get that whole meringue in your mouth at once?

0:24:200:24:23

So we've got the results now.

0:24:300:24:31

Later, Amanda gets busy with her calculator

0:24:340:24:36

and tots up the final calorie count.

0:24:360:24:39

OK, Xand, you're on the high fat diet, you had 825 calories.

0:24:390:24:42

-That's quite a lot.

-Yes, that's a big meal.

0:24:420:24:45

Yeah, but you, Chris, on your carb blowout, you had, er 1,250 calories.

0:24:450:24:49

-Whoa!

-That's...that's half your calories for the day right there.

0:24:490:24:52

-That's half my whole day's calories in a single sitting.

-Yeah.

0:24:520:24:55

For me, the interesting thing is, I ate more food than you,

0:24:550:24:59

so calories do not necessarily make you feel full,

0:24:590:25:02

and I was then hungrier quicker,

0:25:020:25:05

so this really simple idea

0:25:050:25:07

that we kind of learn that if you feel hungry

0:25:070:25:09

you eat a meal and then you stop feeling hungry,

0:25:090:25:12

even that is not really true.

0:25:120:25:14

You can eat an enormous meal and end up being hungrier than the person

0:25:140:25:17

who ate...you know, you ate almost the number of calories I did.

0:25:170:25:20

What's going on there, then? Why is that?

0:25:200:25:22

There's quite a big body of research that suggests that

0:25:220:25:24

high protein diets make you feel fuller.

0:25:240:25:26

It's the protein that's making me feel full?

0:25:260:25:28

You don't really eat high fat on its own,

0:25:280:25:30

you don't eat butter on its own or glug down olive oil on its own.

0:25:300:25:32

Xand might.

0:25:320:25:34

It comes with protein and makes you feel fuller than the carbohydrates.

0:25:340:25:37

That's probably number 1.

0:25:370:25:39

But it's more than that.

0:25:420:25:44

Protein and sugar have very different effects on ghrelin

0:25:440:25:47

the hunger hormone.

0:25:470:25:49

The more ghrelin you have in your body, the hungrier you'll feel.

0:25:490:25:54

Protein suppresses ghrelin for longer than sugar.

0:25:550:25:59

The problem with sugar is that it's an easy source of calories,

0:26:020:26:06

and that can make you fat.

0:26:060:26:08

But you can end up eating fewer calories on a high fat diet

0:26:090:26:13

because of the interaction with ghrelin.

0:26:130:26:16

Not all fats are the same,

0:26:180:26:20

and fortunately on my diet I'm mostly on the good stuff.

0:26:200:26:22

I'm eating lots of monosaturated and polyunsaturated fats,

0:26:220:26:26

the kind of thing you find in eggs, olive oil, and oily fish.

0:26:260:26:31

And that's all good for you.

0:26:310:26:33

Now, I'm also eating quite a lot of saturated fat,

0:26:330:26:35

which is the kind of thing you find in foods like meat and cheese.

0:26:350:26:39

Now this stuff you're not recommended to have more

0:26:390:26:41

than 30 grams a day because it raises your LDL,

0:26:410:26:44

your bad cholesterol, but recently an increasing

0:26:440:26:47

number of scientists are saying this may not actually be true.

0:26:470:26:50

But there is no debate about trans fats.

0:26:500:26:53

Now, trans fats are found in a wide range of manufactured foods

0:26:530:26:56

like cakes and cookies, things like this, and they're not good for you.

0:26:560:27:00

And what they do is they not only raise your LDL,

0:27:000:27:02

your bad cholesterol, but they lower your HDL, your good cholesterol.

0:27:020:27:07

Fortunately, on my diet I'm not allowed to have any of them.

0:27:070:27:10

A gram of fat also has over twice as many calories as a gram of sugar.

0:27:180:27:23

And our bodies turn dietary fats into body fat more easily

0:27:260:27:30

than it does with sugar.

0:27:300:27:32

Ultimately, of course, fat and sugar are sources of energy.

0:27:330:27:37

So what we really want to know is how they work to fuel our bodies.

0:27:380:27:43

It's now going to get personal and painful.

0:27:430:27:46

What we're going to do is we'll have five minutes steady peddling away,

0:27:480:27:52

I'm going to talk to you, I want to keep a nice conversation going,

0:27:520:27:55

and then we're just going to start ramping it up a little bit.

0:27:550:27:58

We set up another test, this time on a bike.

0:27:580:28:01

This is very fun, I haven't used one of these before.

0:28:020:28:05

Have you not? Oh, you're going to hate it soon.

0:28:050:28:07

We've recruited Nigel Mitchell

0:28:070:28:09

from the first ever British Tour de France winning cycling team

0:28:090:28:13

to help us.

0:28:130:28:14

-Perfect, perfect, perfect. Just nice.

-Keeping up so far.

0:28:140:28:17

This is the first exercise of any kind we've done in our diet,

0:28:200:28:23

and we've not eaten for 12 hours.

0:28:230:28:26

Your cadence looks nice. Drop a gear.

0:28:260:28:29

We're 15 minutes into an hour-long session.

0:28:320:28:35

Nigel wants to completely exhaust us.

0:28:350:28:37

-Ramp this up a little bit to 18mph now.

-Drop a gear?

-Drop a gear.

0:28:390:28:43

Yeah, we're starting to work a bit more now.

0:28:450:28:47

It's the first step in a particularly sadistic experiment,

0:28:490:28:52

to see if fat or sugar is the best macronutrient for exercise.

0:28:520:28:56

So, how much difference does the kind of nutrition science

0:29:010:29:04

you're doing make to a team?

0:29:040:29:06

I want to use foods to fuel them,

0:29:060:29:08

I want to use foods for them to recover.

0:29:080:29:10

So the foods that we give the guys

0:29:100:29:12

is a mixture of bars and gels and protein.

0:29:120:29:15

Breakfast, we use a lot of porridge.

0:29:150:29:17

Now you can't get porridge on the continent,

0:29:170:29:19

so for the Tour de France and all this we actually buy

0:29:190:29:22

the porridge oats in this country and we take them out there.

0:29:220:29:25

And last year it were about three weeks before the tour

0:29:250:29:28

and I go around my local supermarket

0:29:280:29:30

and I've got all my Sky kit on cos I'm working, and I've

0:29:300:29:32

got a trolley full of porridge oats, I've got about 80kg of trolley oats.

0:29:320:29:36

I put them on the conveyor belt and we take them through,

0:29:360:29:39

and the woman on the conveyor belt,

0:29:390:29:41

woman on the till just brings you down to Earth, she says,

0:29:410:29:43

said to me, "So do you work in a care home or something, you know,

0:29:430:29:46

"all this porridge oats that you've got?"

0:29:460:29:48

45 minutes in, Nigel takes a blood sample.

0:29:530:29:56

'The blood test confirm just how bad we feel.

0:29:590:30:03

'Chris is burning sugar like crazy and his blood sugar levels

0:30:030:30:07

'plummet from 4.7, where they were at the start of the test, to 2.7.

0:30:070:30:11

'I'm faring better. My blood sugar has fallen by only about 25%.'

0:30:130:30:18

This is doing exactly what we wanted it to do.

0:30:220:30:25

Last minute, then, boys. Just keep it like this.

0:30:290:30:34

'An hour of punishing exercise without food has pushed us to the

0:30:340:30:38

'edge of our physical capabilities.'

0:30:380:30:39

Yeah, I feel like I'm out of juice.

0:30:420:30:44

'We're now both exhausted and empty,

0:30:490:30:51

'which allows Nigel to test how fat and sugar fuel the body.'

0:30:510:30:56

OK, boys, so we've done the hour on the turbo trainers at the top,

0:30:560:31:00

we've pushed your blood sugars down, so you're just mild hypo...

0:31:000:31:04

Get off! What we're going to do now is race up the hill.

0:31:040:31:08

Now, we've got some food, so for Xander, we've got butter,

0:31:080:31:12

so it's one pack of butter, please. Just one.

0:31:120:31:15

And then I want you to take one in your pocket for eating

0:31:150:31:18

on the way up, and then we've got a gel for you.

0:31:180:31:21

-The same number of calories in the gel.

-Roughly.

0:31:210:31:24

We've got the same number of calories in the gel as the butter.

0:31:240:31:27

But the gel is sugar.

0:31:270:31:29

'There's nothing special about either the butter or the gel.

0:31:290:31:32

'They're basically fat and sugar.'

0:31:320:31:35

So, right, I want you to ride at my pace.

0:31:350:31:38

I want us to control this, as we're going up there.

0:31:380:31:41

A little bit easier on the gears. That's it, perfect.

0:31:410:31:44

You're in the same gear.

0:31:440:31:45

'Now it's time for the race up the hill, between fat in red

0:31:450:31:48

'and sugar in blue.'

0:31:480:31:50

When we turn right, we're going to start just lifting it slightly.

0:31:500:31:54

-Are you OK?

-Yeah, I'm all right.

-Just push on a bit more, then.

0:31:540:31:58

'We're climbing the iconic and steep Box Hill in Surrey.'

0:31:590:32:04

'And in the next few seconds,

0:32:040:32:06

'it's going to turn into a fat versus sugar race to the summit.'

0:32:060:32:10

-What's your heart rates now, boys?

-177.

0:32:100:32:13

154.

0:32:130:32:15

Just keep next to each other, if you can.

0:32:150:32:18

OK? Right, are you ready, both of you? Go!

0:32:180:32:21

Keep it going. Keep it going.

0:32:240:32:27

'In the race to the top, Chris soon speeds away from me.'

0:32:310:32:34

He just keeps getting further away

0:32:380:32:40

and I cannot make my legs go any faster.

0:32:400:32:45

It's like I'm stuck in one gear.

0:32:450:32:48

'With my heart rate pumping at 200 beats per minute,

0:32:530:32:57

I just manage to get to the top.'

0:32:570:33:00

Just looking at you two, you've got a big smile on your face.

0:33:000:33:03

You won the King of the Mountains there, Chris.

0:33:030:33:06

Xander, you bunked out. But this is the thing.

0:33:060:33:09

This is what we're trying to show.

0:33:090:33:11

When you're really trying to push it, your body needs the sugar.

0:33:110:33:14

It needs the carbohydrates. I want to measure the sugars again.

0:33:140:33:18

7.1, your blood sugar now. 7.1.

0:33:210:33:24

'Chris's blood sugars are so high because the sugar gel

0:33:260:33:29

'he consumed half an hour ago is still pulsing through his body.

0:33:290:33:32

'And that gave him the fuel to power his muscles up the hill.

0:33:350:33:39

'But what about my blood sugar levels?'

0:33:400:33:44

5.1, now that's interesting.

0:33:440:33:46

All we've given you to eat is fat and we can't convert fat into sugar.

0:33:460:33:51

'Completely deprived of glucose,

0:33:510:33:54

'our bodies have a dramatic way of making sugar.

0:33:540:33:58

'Protein in the form of muscle converts into amino acids,

0:33:580:34:02

'which are then turned into glucose

0:34:020:34:04

'and that's pumped into the blood, raising blood sugar levels.

0:34:040:34:08

'So there's no question you can power your body without sugar,

0:34:130:34:17

'but there is a price to pay.'

0:34:170:34:19

Your blood sugars going up has got to be coming from the protein.

0:34:190:34:23

He's burning muscle to make sugar.

0:34:230:34:25

-He's burning muscle to make sugar now.

-I feel quite rubbish.

0:34:250:34:29

This is the last state you'd want one of your athletes to be in.

0:34:290:34:32

If we'd got one of our riders and they were in your state in the

0:34:320:34:35

Tour de France then I'd be looking for a new job.

0:34:350:34:40

So we had identical turbos, we've got identical bikes, we've got

0:34:400:34:44

the same tyre pressure, so you're doing the same work...

0:34:440:34:47

We've got effectively the same person.

0:34:470:34:49

Effectively the same person genetically.

0:34:490:34:52

The big difference is the diet that you've been following.

0:34:520:34:56

What's amazing about that is I haven't eaten any carbohydrate

0:34:590:35:02

in weeks and my body can still make enough sugar to get me up that hill.

0:35:020:35:06

How have you done this?

0:35:060:35:08

How have you turned your dreadful performance up that

0:35:080:35:12

-hill into a kind of victory for fat?

-I got here, didn't I?

0:35:120:35:16

And... Yes, you did have normal carbohydrate, which is...

0:35:160:35:19

It's a point for me because your body needs carbohydrates to exercise like that.

0:35:190:35:23

And where are you getting the carbohydrate? From your muscles.

0:35:230:35:27

So you do exercise like that all day, you'll actually lose muscle and keep your little belly cos you're

0:35:270:35:31

-not turning that into carbs, are you?

-All right.

0:35:310:35:34

I'll beat you on the way down.

0:35:340:35:36

-Yeah cos you're still fat!

-HE CHUCKLES

0:35:360:35:40

This meal, it should be so good...

0:35:520:35:55

It's missing one essential ingredient.

0:35:550:35:59

And that's fat.

0:36:010:36:02

So it's totally joyless.

0:36:020:36:04

It's just a rubbish end to my day.

0:36:040:36:06

At last, the diets are over.

0:36:120:36:15

And we're back at the lab to find out what effect fat

0:36:150:36:19

and sugar have had on our weight and health.

0:36:190:36:22

OK, chaps. What I need you to do is get stripped off like before.

0:36:230:36:27

'We're with our old friend Richard McKenzie to be weighed and measured.'

0:36:270:36:32

OK, no talking, no moving.

0:36:330:36:35

'Starting, of course, with the machine that measures

0:36:350:36:39

'the percentage of fat and muscle in our bodies.'

0:36:390:36:42

OK, and you're up next.

0:36:430:36:46

'..Then close the door to begin tests.'

0:36:460:36:50

'And he's got some good news and unfortunately, some bad news for us,

0:36:500:36:55

'beginning with the results for the high sugar diet.'

0:36:550:37:00

-Chris, OK, you've lost 1kg of body mass.

-Is that good?

0:37:000:37:04

You've been eating as much as you want of junk for a month

0:37:040:37:09

and you've lost a kilo.

0:37:090:37:11

Yeah, it's not bad.

0:37:110:37:13

Half of that has come from body fat

0:37:130:37:15

and the other half has come from muscle mass.

0:37:150:37:18

-Oh, really? So I have lost muscle as well?

-Yes.

-What about him?

0:37:180:37:22

-I feel like I've lost weight.

-You have.

0:37:220:37:25

You've lost around 4kg of body mass.

0:37:250:37:29

'On the high fat diet, Xand has lost more weight.

0:37:290:37:32

'To be more accurate, 3.5 kilos in a month.'

0:37:320:37:36

So, where has that weight loss come from?

0:37:360:37:38

2kg has come from muscle mass, 1.5 has come from fat mass.

0:37:380:37:42

I've lost weight, which is great,

0:37:420:37:44

and I've lost a legitimate 1.5 kilos of fat.

0:37:440:37:47

In four weeks, that's really good.

0:37:470:37:50

On the face of it, that's very good.

0:37:500:37:52

Yeah, on the face of it,

0:37:520:37:54

but you've lost 1.5 kilos of fat and you've lost 2 kilos of muscle.

0:37:540:37:58

Your brother's right. We have to look at it in a bit more detail

0:37:580:38:01

and losing body weight is an ideal goal in some circumstances,

0:38:010:38:05

but you've lost 2kg of muscle mass and that isn't healthy.

0:38:050:38:09

Why is it so bad to have lost these 2 kilos of muscle?

0:38:090:38:11

If you lose muscle mass, with disease or ageing,

0:38:110:38:15

you are more likely to visit the hospital more often

0:38:150:38:17

and have a poor life expectancy.

0:38:170:38:20

-Really?

-Yes.

-That bad?

-Yes.

0:38:200:38:22

That's a really important counterintuitive thing,

0:38:220:38:25

I think, that we're going to lose weight, go on a diet, we don't

0:38:250:38:28

think too much about exercise, and it can be really bad for you.

0:38:280:38:32

'Nervously, we went through the same battery of tests as we did

0:38:390:38:43

'a month ago. First, we checked our cholesterol.'

0:38:430:38:48

'We thought that because Xand was eating so much fat on his diet,

0:38:480:38:51

'his levels would be much higher.

0:38:510:38:53

'What was amazing is that they were nearly exactly

0:38:530:38:56

'the same as they were at the start of our diets.

0:38:560:39:00

'In fact, there was little or no change for either of us.'

0:39:000:39:03

One minute to finish.

0:39:050:39:07

'Finally, we tested our insulin,

0:39:100:39:12

'the hormone that regulates the level of sugar in your blood.'

0:39:120:39:16

Urgh!

0:39:160:39:18

'Naturally enough, on the high sugar diet, I went first.'

0:39:180:39:23

Your body's ability to produce insulin improved.

0:39:230:39:27

-That is the opposite...

-Totally the opposite

0:39:270:39:30

of I think what we would expect, most doctors would expect,

0:39:300:39:33

what most people in the street would expect.

0:39:330:39:37

Probably just got used to dealing with the sugar,

0:39:370:39:40

the glucose intake and therefore, responding by producing insulin.

0:39:400:39:44

A bit like if I'd been drinking a lot for the month,

0:39:440:39:47

my liver would up-regulate the enzymes to deal with the alcohol.

0:39:470:39:50

It's almost the same thing.

0:39:500:39:52

Because I've been eating loads of sugar,

0:39:520:39:55

-I've become better at managing it.

-You're better at producing insulin.

0:39:550:39:59

Is that good or not?

0:39:590:40:01

Um...

0:40:010:40:03

In the short term, it is good, but long term,

0:40:030:40:05

it might produce a problem.

0:40:050:40:08

'An unexpected result for me.

0:40:080:40:11

'But what about Xand on the high fat diet?'

0:40:110:40:16

What is worrying is your body is not responding to

0:40:160:40:18

insulin as well as it did.

0:40:180:40:20

If you eat too much fat, that can stop your body responding to

0:40:200:40:25

insulin and it also can tell your body to produce more glucose.

0:40:250:40:29

So how serious is this? It's only a month. Is this a big difference that you're seeing?

0:40:290:40:33

Actually, it is a big difference.

0:40:330:40:35

What we've seen is your blood glucose has climbed from 5.1,

0:40:350:40:39

which it was before the diet, which wasn't great to start with,

0:40:390:40:43

but still in a healthy range, to 5.9.

0:40:430:40:47

You're only 0.2 away from being pre-diabetic.

0:40:470:40:51

Wow!

0:40:510:40:53

In a month, I've done myself some proper damage.

0:40:530:40:56

-This isn't good for me at all.

-It's not good for you.

0:40:560:40:59

That's the first thing. You should stop that diet.

0:40:590:41:02

Eventually, your body will stop producing insulin

0:41:070:41:10

if you carry on down this path.

0:41:100:41:11

I've been on a no-sugar diet

0:41:110:41:13

and I just would have thought I'd be making less insulin

0:41:130:41:16

and needing less insulin. You're saying I'm making more insulin,

0:41:160:41:20

my body isn't reacting to it as well

0:41:200:41:22

and I'm well down the road to diabetes,

0:41:220:41:24

which is, which is bad news.

0:41:240:41:26

It's bad news, you're heading that way.

0:41:260:41:28

So I thought if you eat lots of sugar,

0:41:350:41:37

you make lots of insulin and that's bad,

0:41:370:41:39

but it turns out me eating lots of fat makes my body insulin-resistant

0:41:390:41:43

so I make more insulin and that's worse.

0:41:430:41:45

So I'm...I'm doing really...

0:41:450:41:47

Like, I'm close to being diabetic now, I'm not...I'm not well!

0:41:470:41:50

I mean, was wrong too. Like I...so I thought, "Well, I'm having coffee,

0:41:500:41:53

"I can't have my cream in it, so I'll put in lots of sugar,"

0:41:530:41:55

so I ate so much more sugar that I normally would...

0:41:550:41:58

-And I'd have thought that would make you diabetic or close to it.

-That's...that's, I think we all,

0:41:580:42:02

that's the received wisdom of becoming diabetic is about eating sugar.

0:42:020:42:05

When are we ever going to learn that if you...it's never about one thing.

0:42:050:42:09

We say, "Oh, it must be fat or it must be sugar..."

0:42:090:42:11

No, it is ALWAYS more complicated than that. Always

0:42:110:42:14

It's like a really basic rule in life, isn't it? If someone

0:42:140:42:17

is selling you one simple solution to a problem that everyone has,

0:42:170:42:20

-it probably isn't going to work.

-No.

0:42:200:42:22

As doctors, we know we have got to be careful

0:42:390:42:42

about extrapolating too much from our own experience.

0:42:420:42:47

Human physiology can be extremely complicated.

0:42:470:42:50

Being on a low-fat or a low-carb diet yourself, you learn all kinds

0:42:580:43:02

of things that you could never get from reading about it in a paper.

0:43:020:43:05

You learn about the experience of being on it,

0:43:050:43:08

whether or not it's fun, whether or not it's nasty, how it feels.

0:43:080:43:12

But the numbers that you get from an experiment

0:43:120:43:14

with just two people aren't definitive.

0:43:140:43:17

They're interesting, but they don't tell you enough.

0:43:170:43:19

To get definitive information from those numbers,

0:43:190:43:22

you have to look at the experiments

0:43:220:43:24

that are being done on thousands of people.

0:43:240:43:27

Over the last few years,

0:43:350:43:37

as the world's got fatter and more unhealthy,

0:43:370:43:39

finding an answer to the fat-versus-sugar question

0:43:390:43:42

has become even more pressing.

0:43:420:43:43

One of Britain's leading nutritionists, Professor Susan Jebb,

0:43:510:43:55

has been researching this for more than a decade.

0:43:550:43:58

And she started with a simple observation.

0:43:580:44:01

We've been looking at this for...for many years

0:44:010:44:03

and I guess what I struggle with is the idea that,

0:44:030:44:06

you know, people start off thin, or lean...

0:44:060:44:09

-Uh-huh.

-..and at some point during their lives,

0:44:090:44:12

many people end up gaining weight, becoming fat...

0:44:120:44:15

This is me at the moment.

0:44:150:44:16

And a proportion of those go on to become sick and they develop

0:44:160:44:19

illnesses, like cardiovascular disease or...or diabetes.

0:44:190:44:24

We're in no doubt about this link, that being fat makes

0:44:260:44:28

a lot of people, not everyone, but a lot of people ill.

0:44:280:44:31

Absolutely, increases your risk of heart disease,

0:44:310:44:34

of cancer and of diabetes.

0:44:340:44:35

-OK.

-So is it something about their diet which alters that risk?

0:44:350:44:39

We looked at um...at the amount of fat or carbs or indeed protein...

0:44:390:44:46

'So she set up a series of long-running, comprehensive studies

0:44:460:44:50

'to see what effects feeding people fat,

0:44:500:44:53

'sugar and protein had on their health and well-being.'

0:44:530:44:56

And more than that, we've tried to study the differences

0:44:560:44:59

in these groups, so we've been interested in saturated fat...

0:44:590:45:03

'She fed them bad fats - saturated fats,

0:45:030:45:06

'and good fats - monounsaturated fats.

0:45:060:45:09

'She did the same with carbohydrates,

0:45:090:45:12

'feeding people low and high GI, whole grains and refined grains.'

0:45:120:45:15

Maybe is about the fibre in the food or maybe is about sugar.

0:45:180:45:22

'For ten years,

0:45:240:45:26

'she conducted a series of detailed scientific studies

0:45:260:45:29

'into which was worst - fat or sugar.'

0:45:290:45:33

So I'm on tenterhooks, like, so what did you find?

0:45:330:45:35

You know, the changes that we got were important,

0:45:350:45:39

but they were quite modest.

0:45:390:45:40

They were surprisingly small, much smaller than I was anticipating.

0:45:400:45:46

And there are clear benefits

0:45:460:45:48

of a little bit more monounsaturated fats,

0:45:480:45:51

some benefits of low GI, some of more fibre,

0:45:510:45:54

but I really don't think we could say that a diet

0:45:540:45:58

which had some extreme composition was really a revolutionary answer.

0:45:580:46:05

What her study showed was that changing fat or sugar on their own

0:46:080:46:13

had a very small effect.

0:46:130:46:14

Especially when compared to the effect of losing or gaining weight.

0:46:190:46:24

So what is it that we're eating

0:46:330:46:35

that's making us fatter and unhealthier?

0:46:350:46:38

Unlikely as it may seem, the first clue in solving that puzzle

0:46:380:46:43

might lie in this tempting tray of doughnuts.

0:46:430:46:46

What I want you to do is look at this tray of doughnuts

0:46:510:46:53

and think about which one you'd choose if you could have any of them.

0:46:530:46:57

Got it?

0:46:570:46:59

Now, this is like a card trick,

0:46:590:47:00

I want you to remember the doughnut you chose and we're going to see

0:47:000:47:03

if the people in New York choose the same one as you.

0:47:030:47:07

All you have to do is choose a doughnut.

0:47:070:47:09

Ah, it's easy.

0:47:090:47:11

I'm going to find out if people in London

0:47:180:47:20

have the same taste in doughnuts as people in New York.

0:47:200:47:23

Right, do you want a free doughnut?

0:47:230:47:26

Er...I would like this one.

0:47:260:47:28

-The same one.

-Yeah, yeah, yeah.

0:47:280:47:29

So can I offer you a doughnut?

0:47:320:47:34

Yeah, go for it, go for it, yes!

0:47:340:47:37

I'm on a diet.

0:47:370:47:38

XAND LAUGHS

0:47:380:47:39

-Is that good?

-Yeah, it's good.

0:47:410:47:42

Everyone pick a doughnut.

0:47:440:47:46

-That's my favourite one.

-Is it?

-It's my favourite one as well.

0:47:470:47:50

You said that was your favourite one, why?

0:47:520:47:54

Just cos I've tried practically all of them

0:47:550:47:57

and I just like this one.

0:47:570:47:59

-Guys, thank you very much.

-Thank you!

-Enjoy your day!

0:47:590:48:02

So it's really interesting - all the glazed doughnuts have gone,

0:48:020:48:04

only one person picked the chocolate one.

0:48:040:48:06

Everyone seems to be going for the glazed ring.

0:48:060:48:10

Let's see if that continues.

0:48:100:48:12

'So why is that? What's so special about this particular doughnut?

0:48:130:48:19

'The doughnut preferences of Londoners and New Yorkers

0:48:240:48:27

'is in fact a clue to what we think is some of the most intriguing

0:48:270:48:31

'new science in nutrition.

0:48:310:48:32

'The real work is being done with rats and what they like eating.

0:48:340:48:38

'Everyday rodents who work with Professor Paul Kenny,

0:48:400:48:43

'a world-renowned researcher in the neurobiology of obesity

0:48:430:48:47

'and, rather interestingly, addiction.

0:48:470:48:50

'He devised a series of elegant experiments to work out

0:48:500:48:54

'what foods we like and why.

0:48:540:48:55

'The first thing he did was feed his rats sugar.

0:48:580:49:00

'And they could have as much as they wanted.'

0:49:000:49:02

The animals, of course, enjoy them and they'll consume vigorously,

0:49:040:49:07

but they tend not to gain weight, because what they do is

0:49:070:49:10

they adjust the consumption of other macronutrients to compensate.

0:49:100:49:13

So, on average, animals with access to high-sugar solutions

0:49:130:49:17

consumed the same amount of calories each day as they would

0:49:170:49:20

if they weren't having access to those solutions.

0:49:200:49:22

Really? So if you let a rat drink all the soda it wants to,

0:49:220:49:26

or you let it have unlimited access to sugar, it doesn't get fat?

0:49:260:49:30

Typically, no.

0:49:300:49:32

'Then, he gave them as much fatty food as they wanted.'

0:49:320:49:36

If you just give them access to fat,

0:49:360:49:38

they will gain some weight, but really not that much,

0:49:380:49:40

and what you find is they don't eat as much, physically eat as much

0:49:400:49:44

food as they would've before, the reason being

0:49:440:49:46

that they know that the fat is high in calories

0:49:460:49:48

and their body is quick to deal with that.

0:49:480:49:50

They have signals that tell them, "You've had enough, stop eating."

0:49:500:49:54

'And there's something simple you can do at home to get

0:49:540:49:56

'a sense of what Professor Kenny's been studying.'

0:49:560:49:59

This is double cream and it's thick,

0:50:020:50:05

it's luxurious, it's rich,

0:50:050:50:08

it's creamy...

0:50:080:50:09

..and it's really boring.

0:50:120:50:14

This is sugar.

0:50:140:50:16

After even with one mouthful, it's overpowering.

0:50:230:50:29

BUT if we mix them together...

0:50:310:50:33

Now, that stuff I could eat all day,

0:50:420:50:44

and in fact, we do eat this all the time,

0:50:440:50:47

cos basically, what we've just made is ice cream.

0:50:470:50:50

Now, this ice cream is absolutely delicious and the reason it tastes

0:50:530:50:57

so good is because the combination of fat and sugar is unbelievable.

0:50:570:51:01

Mm.

0:51:030:51:04

So, Professor Kenny took this simple insight

0:51:070:51:10

and fed his rats foods that were high in fat and sugar.

0:51:100:51:14

So what happened when you fed cheesecake to rats?

0:51:140:51:17

They practically stopped eating the regular, healthy food that

0:51:170:51:21

was there, but they didn't binge on the high fat, high sugar stuff,

0:51:210:51:24

they grazed on it, but that was their main source of calories.

0:51:240:51:27

This is the going to the fridge and just having a spoonful

0:51:270:51:29

-of ice cream every 20 minutes.

-Precisely, yeah.

0:51:290:51:31

You know, you get up and you eat, but if you're going to eat

0:51:310:51:34

it's for that type of food and you tend to eat much more frequently.

0:51:340:51:37

You're not gorging on it, but that's what you eat continuously.

0:51:370:51:39

And those animals gained a massive amount of weight,

0:51:390:51:42

they really gained a lot of weight, and they became sedentary.

0:51:420:51:45

They slept a lot, didn't move around,

0:51:450:51:46

but that was where they got their calories from.

0:51:460:51:48

What Professor Kenny's discovered is that,

0:51:510:51:54

unlike fat and sugar on their own,

0:51:540:51:56

the rats had no off switch when it came to fat and sugar combined.

0:51:560:52:00

The combination of fat and sugar is completely different

0:52:000:52:04

than either macronutrient alone, and it tastes remarkably good.

0:52:040:52:07

And so what you have are these systems in the brain that are there

0:52:100:52:14

to respond to not whether you need food to live,

0:52:140:52:16

but whether you like using food,

0:52:160:52:19

and they're engaged, they're called hedonic systems.

0:52:190:52:22

It's much like what happens with drug addiction.

0:52:240:52:27

You don't need heroin, you don't need cocaine,

0:52:270:52:29

it's got no nutrient value, it's got no caloric value,

0:52:290:52:32

it doesn't do anything for you except make you feel good.

0:52:320:52:35

And it's exactly those hedonic systems in the brain that we think

0:52:380:52:41

are being impacted far more when you consume food

0:52:410:52:45

that's rich in fat and sugar, than consuming either sugar or fat alone.

0:52:450:52:49

When you think about it, we all know we need to eat to live.

0:52:520:52:55

But what Professor Kenny's discovered is that the combination

0:52:590:53:02

of fat and sugar supercharges the brain's reward system,

0:53:020:53:06

overpowering its ability to tell us to stop eating.

0:53:060:53:10

And it's a manufactured combination,

0:53:130:53:16

you can't find it anywhere else in nature.

0:53:160:53:18

But here's what's even more remarkable.

0:53:250:53:27

He's discovered that his rats didn't just like

0:53:290:53:31

a mixture of fat and sugar,

0:53:310:53:33

the ratio of fat to sugar was crucial to how much they liked it.

0:53:330:53:38

When I looked at the composition of cheesecake and I was surprised.

0:53:400:53:43

It had a highest percentage of fat of any food item

0:53:430:53:47

that we looked at that wasn't actually pure fat,

0:53:470:53:49

and it had remarkably high levels of sugar. So it was

0:53:490:53:52

-the combination...

-What's the ratio of fat and sugar in cheesecake?

0:53:520:53:55

-It's pretty much 50/50.

-Really?

0:53:550:53:57

It's about a half fat and the rest of it sugar

0:53:570:53:59

with various other things to keep the whole product together.

0:53:590:54:02

-OK.

-So it's basically half fat and half sugar.

0:54:020:54:05

Chaps, can I offer you doughnuts?

0:54:050:54:06

OK, there you go, go for it.

0:54:060:54:08

-I like these ones.

-Tuck in, there's no trick.

0:54:080:54:11

Now remember, the most popular doughnut was this one,

0:54:130:54:16

the glazed ring,

0:54:160:54:18

and there's something really special about this doughnut,

0:54:180:54:21

it's got an exactly 50/50 mixture of fat and sugar.

0:54:210:54:25

The pink one, that's got extra sugar on the top,

0:54:250:54:28

and this one is filled with cream.

0:54:290:54:32

So there's no question,

0:54:330:54:34

we absolutely love this combination of fat and sugar.

0:54:340:54:38

It's no surprise that people liked this doughnut.

0:54:400:54:43

It tends to be the bestseller on both sides of the Atlantic.

0:54:430:54:46

The fact that the world is getting fatter is a new phenomenon,

0:54:520:54:55

and what seems to be driving it,

0:54:550:54:57

at least according to Professor Kenny, is processed food,

0:54:570:55:00

because that's where you find this deadly combination

0:55:000:55:03

of fat and sugar that you don't find anywhere else in nature.

0:55:030:55:07

And what this does is it fundamentally interferes

0:55:070:55:11

with our mechanisms of self-regulation and reward.

0:55:110:55:14

It seems that it's fat and sugar together,

0:55:220:55:25

not fat or sugar alone, that's the real problem.

0:55:250:55:28

And Chris wanted to find out from Professor Jebb what we could do about it.

0:55:300:55:35

When people tell me they crave sugar,

0:55:360:55:38

I say, "What, sugar out of the sugar bowl?

0:55:380:55:41

"Oh, no, no, no." Or fat, pats of butter? Generally not.

0:55:410:55:44

What people really seem to desire, whether that's physiological

0:55:440:55:48

or whether it's a learnt behaviour is these fat/sugar combinations.

0:55:480:55:52

They are very energy dense, so they pack the calories in,

0:55:520:55:56

and they are unbelievably pleasurable and attractive.

0:55:560:55:59

Are these temptations for you as well?

0:55:590:56:01

Oh, I think they're temptations for most of us.

0:56:010:56:03

One of the things that I often say

0:56:030:56:05

is it's astonishing that any of us stay slim.

0:56:050:56:09

In a world like this where in Britain we are surrounded

0:56:090:56:12

by pretty delicious, relatively affordable, palatable foods,

0:56:120:56:18

actually you have to exert quite a level of dietary restraint

0:56:180:56:22

if you're not going to effectively just sleep-walk into obesity.

0:56:220:56:26

So I want your top tip,

0:56:260:56:28

a basic rule, like my go to thing when I'm feeling weak.

0:56:280:56:32

By making some pretty modest changes, but right across your diet.

0:56:320:56:36

Certainly cutting out some of those kind of discretionary

0:56:360:56:40

treat type foods which are no longer really treats,

0:56:400:56:44

-they've become everyday items.

-Yes.

0:56:440:56:46

If you take those out you can cut calories

0:56:460:56:48

and you can cut lots of those other nutrients of concern.

0:56:480:56:52

So you end up with a healthier diet

0:56:520:56:54

and one on which you can also lose some weight.

0:56:540:56:57

And I think that really is the secret to developing

0:56:570:56:59

a much more holistic attitude to food,

0:56:590:57:03

which doesn't sort of believe that any one item is a saviour

0:57:030:57:08

or a sinner, it is about the overall balance of the diet.

0:57:080:57:12

We've all heard that before

0:57:200:57:21

but the difference is that we now know our enemy.

0:57:210:57:25

It's not fat.

0:57:270:57:28

And it's not sugar.

0:57:300:57:32

But the deadly, addictive,

0:57:330:57:35

delicious mixture of fat and sugar combined.

0:57:350:57:39

What's amazing to me about all this is that

0:57:420:57:45

I've been a doctor for ten years,

0:57:450:57:47

I've spent six years at medical school,

0:57:470:57:48

and I thought I knew a lot of this stuff and I just didn't,

0:57:480:57:52

like I was wrong about a lot of stuff.

0:57:520:57:54

So basically what I get out of this is

0:57:540:57:56

I have to avoid the processed food, the doughnuts, the ice cream,

0:57:560:58:00

the cheesecake, that sort of 50/50 fat/sugar mixture

0:58:000:58:04

I cannot stop eating, and it's... and that's the problem.

0:58:040:58:07

So I'm going to cut those out completely.

0:58:070:58:09

So that where I end up is going all faddish diets,

0:58:090:58:12

all faddish diets, are wrong and misguided,

0:58:120:58:16

-all of them.

-Yeah.

0:58:160:58:17

And doing exercise is really important.

0:58:170:58:19

You need to keep the muscle because muscle is an endocrine organ

0:58:190:58:22

that affects your whole metabolism.

0:58:220:58:25

So, in the end, as doctors, we'd love to be able to give

0:58:250:58:27

one simple rule or give you a pill that would fix all this,

0:58:270:58:30

but in the end we can't.

0:58:300:58:32

-It's up to you.

-It's up to YOU.

0:58:320:58:34

All right, it's up to... It's up to you too.

0:58:340:58:37

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