All language subtitles for BBC.Horizon.2013.The.Truth.About.Taste.720p.HDTV.x264.AAC.MVGroup.org.eng

In a warm climate, in Florida,

this man is chasing his dream.

He's in pursuit
of the perfect tomato.

There are people
who are growing up today

who have never tasted
a really good tomato,

that don't even know
what a good tomato is

and we need to fix that.

He wanted to create a fruit that
is juicier, tastier and sweeter

than any you're likely to find
on a shelf.

And he's done it.

The reason these tomatoes are sweet

is because of smells he's captured
in these jars.

So he may have found a way
of making things taste sweeter

without adding any extra sugar.

And that's because of a trick

that happens in your brain.

Now, can you fool the brain?

Can you provide it with sweet
that's safe and that isn't sugar?

I think that's the Holy Grail.

Taste is our most sensuous
and indulgent of senses.

It turns out that the story
of why we like what we like

is a lot more surprising
than you think.

Food... Mmm, yummy!

SHE CHUCKLES

We all have a favourite food.

All the textures, the flavours,

the smells...and it's just wonderful!

For some of us, it's sweet.

Chocolate brownie
or rich chocolate torte.

For others, it's savoury.

I love shellfish
and I love octopus.

That's probably my ideal.

What you love eating
is as unique as a fingerprint.

Cream cheese, like, really fattening
cream cheese, like,

you know, that's just
delicious and that.

Of all our senses, taste is the one
we most associate with pleasure.

Good old apple crumble
and sticky toffee pudding.

Crunchy on the outside
and warm on the inside.

Yet the story of what happens when
you taste is anything but simple.

If you really want to understand
how taste works,

you need an environment far removed
from the clutter of a kitchen.

Today, a group of people
have come to this lab in Berkshire

to undergo a rather special test.

They want to find out
whether they have what it takes

to be a professional taster.

Someone who can judge the taste
of the food you might one day eat.

There'll be two parts to the test.

The first part will be a
familiarisation of the five tastes

and I will give you five samples

and take you through
what these five samples are.

Most of these tastes
are ones we all recognise.

746 - this one is sweet.

625 - this sample is sour.

Bitter and salty
are also pretty well known.

But the fifth one, savoury,
or umami, is a lot trickier.

198 - and take a couple of sips,

really focus on this one -

this one is umami.

When it comes to our would-be
professionals,

it's not a familiar one.

There was one, I admit,
that I didn't know.

Um... Mumba...that one.

Is it amani?

That was a bit...
Never heard of that one before.

Never heard of...what is it, umagi?

I don't even know what that is,
but I'm going to find out today.

With the familiarisation over,
the test really starts.

They are given much weaker
versions of the basic five tastes.

They have to work out
which is which.

What makes it so difficult
is that there are no other cues

that we all normally
take for granted -

no colours, textures, smells
to help them decide.

No talking during this test,

it's your own opinions that I want.

746.

625.

Already, some candidates
are finding it easier than others.

Bitter and sour are often
the hardest to tell apart.

There were some that I thought
I was OK with,

but, on the whole,
it was quite difficult.

I think the umami was pretty easy
to work out.

Very difficult to distinguish
the flavours,

they were quite slight,
very delicate.

The salty was OK and the sweet.

Bitter was very hard.

But now, tasters have to undergo
a second test

that they weren't expecting.

They will have to identify
a different variety of substances,

but not with their mouths.

They'll be given a variety
ranging from rosemary,

fresh ginger...

..to vanilla.

What I'd like you to do is

write next to the corresponding
three-digit code

what aroma you think is in the tube.

This test will be even harder
than the first.

If you are not entirely sure
what it is that you can smell,

put something down
that it reminds you of

and you still might get a point
for that.

I'm normally the one that says,
"Oh, can you smell that?"

and nobody else can, so let's see.

I think I probably got
about half of them.

I'd say it's pretty good.

Maybe a bit easier than the taste.

It was harder than I thought,
actually.

I haven't actually got the actual
smell, but I know what it's like.

Today, only 5 out of the 14
were found to have the potential

to go on to be a professional.

That's normal for a test like this.

They could be the ones who taste
the food you'll have tomorrow.

I didn't like curry, mushy peas.

Taste is bizarre.

Mushrooms, I couldn't stand them.

Anything like whelks.

I used to be scared of mushrooms.

It doesn't even stay the same.

We all remember foods
we used to hate.

Olives, I tried them a few times
and I hated them.

I hated them!
But they're my favourite now.

SHE CHUCKLES

Liver. I like liver now,
but I hated it then.

I used to hate mushrooms

and now, I can think of nothing
better when it comes to a burger

than a Portobello with pesto.

It's clear that each of us

develops a highly individual set of
likes and dislikes over our lives.

But the process by which you acquire
and change your tastes

is starting to reveal its secrets.

At Birmingham University,

Professor Jackie Blissett has been
trying to understand

the very earliest part
of this process.

Children's eating is
absolutely fascinating.

When you think of the individual
differences that you see

in children's willingness,
for example, to try new foods.

That really drove me to try
and understand a little bit more

about the factors that were
either intrinsic to themselves

or in their environments
that make the difference

between those children who are happy
to taste pretty much anything

and the kids who are really,
really reluctant to try.

When it comes to taste,
you're born with some preferences -

they're intrinsic.

Others happen because of tastes
you experience - your environment.

This way, love.

Jackie is trying to discover
how these two fit together.

This is going to be a really special
tasting again, I think.

The children will be offered
eight different foods.

Some they already know
they don't like...

..others are brand new.

Their challenge is to try
to taste them all.

The first child is Abenna.

Her mother has told Jackie
that she is a picky eater.

Have you ever had those before?

No.

Jackie is interested in why
there are ones she doesn't like.

Which one of those do you think
looks the most yummy?

That! That one looks
the most yummy, why?

The pomegranate, cos I've tasted
them before...

Faced with some unfamiliar sights,

Abenna follows her instincts,

instincts we're all born with,

and goes straight
for something sweet.

Babies, very, very early in life

have this preference
for sweeter taste,

not surprisingly, because the taste
of milk is sweet.

High levels of sweetness, fattiness,

all of these things
indicate good calorie sources.

And then, if you had to choose
another really yummy one...

The figs?

Try it.

The sweet tastes go first, so now
her choice becomes more difficult.

I don't like sprouts...

Again, Abenna's instincts cut in -

she's wary of bitter.

Things like this,
it looks all like...

We are all programmed, really, to
avoid bitter tastes wherever we can,

they might be poisonous, they might
have high levels of toxin.

So bitter tastes are often
very problematic

for parents, in particular,
to introduce to their children.

I don't like mushrooms...

They're all squashed. Oh, squashed.

So far, Abenna is reacting as nature
has programmed her to do -

she's drawn to sweet
and tries to avoid bitter.

But now, another influence
starts to exert itself -

her own experience.

Which one do you think looks
the most yummy now?

SHE CHUCKLES

Oh, it's difficult. Sprouts, cos
I've tasted them before. Sprouts?

Do you want to try it?

They're all right.

She's thinks she's chosen
the least worst option,

but then something
telling happened -

this time, the sprout she thought
she hated tasted fine.

Because she'd been exposed
to the vegetable before,

it overcame her intrinsic
dislike of bitter.

When you see something
like vegetables,

children are going to have
to have a number of exposures

to those vegetables
to find them familiar,

to have tasted them often enough

to have acquired a reasonable
preference for them.

So there isn't a magic,
overnight effect.

It is often a long process
of gradually learning to like

the tastes that aren't
particularly innately preferred.

And this is the key to how
we all develop our tastes -

we develop a liking
if we keep tasting it.

Children at around
two or three years old,

if they're relatively fussy eaters,

those patterns track through
childhood and into adulthood,

so it's absolutely important,
really, really important

that dietary range
is as broad as it can be

before those children
reach that kind of age.

What about this one?

What about the litchi,
have you tried that one before?

But there's another surprise

that may explain why you like
some rather strong tastes.

Even when you're tiny.

If a mother is consuming
a large amount

of something like garlic
when she's pregnant,

we know that that flavour passes
into the amniotic fluid,

and some research has shown

that babies who are exposed
to some specific flavours in utero

actually continue to show
preferences for those flavours
later.

Do you want to give it a little try?

And what's true of garlic may also
be true of chilli and onions.

Do you want to try some now?

Mmm...

What we taste when we're little
has a powerful influence on us.

But scientists have also found your
sensitivity changes as you age.

Your sense of bitter fades.

So those foods you found it
hard to like

can become that bit easier
to start to enjoy.

But it isn't as simple as that
for all of us.

Gainesville, Florida.

This is Professor Linda Bartoshuk.

Linda may not be a household name,

but she's probably done more
in her career

to understand your sense of taste

than anyone else alive.

Food, in the sense of taste,

is very much involved
in our appreciation of life,

it produces enormous pleasure.

What intrigued Linda was not just
which tastes we each like,

but how strong some of us
seemed to like them.

Why do some people cover their food
with hot sauces

and others never touch them?

When I started working in taste,
and it was a lot of years ago,

we knew a great deal
about observational tastes,

from people cooking, paying attention
to what they ate,

we didn't know very much
about the mechanisms.

She was interested in how sensitive

different people were
to the same food.

It's easy to do a basic test.

If you are adventurous, you can put
the whole thing in your mouth.

If you want to take it a little
slower, taste the little corner
of the paper,

and if you don't taste it,
put a little bit more in.

Her testing equipment is simple.

A piece of paper soaked
in a very bitter chemical.

I don't really taste anything.

You don't taste it? Very little. OK.

Well, for some, it is.

It's very bitter.

This sort of test has shown
over and over again

that different people
do have different reactions
to the same taste.

Linda wanted to see if there was
an anatomical reason for this.

Her task was daunting.

She had to take an extremely close
look at thousands of tongues.

Taste buds are buried in what
are called fungiform papillae.

They will stand out
when you stain the surface.

But you still have to count them.

Counting papillae is not
the most fun in the world

but the best thing to do
is take a picture.

And if you've got a picture,
you can go back,

look at it, count
and that's what we did.

And indeed the group of people
who were intensely sensitive

actually had more fungiform
papillae.

Those with fewer, tasted less.

Five per six millimetres,
it's that precise,

and you're at the bottom
of the scale.

60 and she has a new name for you -

supertaster.

The people at the end with five

are really having pastel experiences
with taste in food.

The people at the end with 60,

taste in food are neon to them,

they're extremely intense.

Today, Linda's comparing
the tongues of Jenny,

who's thinks she has a very strong
sense of taste,

with Derek, who's thinks he hasn't.

If Jenny is a supertaster, she
should be anatomically different.

I look at this screen
and I can tell right away

this is a supertaster tongue,
this is not.

We see many, many more fungiform
papillae here,

many fewer here,
larger here than these.

And that's typical
of these two groups.

We already know that Jennifer

tastes things more intensely
than Derek,

so I expected her tongue to show that
she's a supertaster and it does.

In fact, around 15% of the people
she studied are supertasters.

But the question is whether
how intensely you taste

affects what you eat.

You know, you might ask, is it better
or worse to be a supertaster?

Well, the truth is, it depends
on what you're asking about.

Supertasters are better off
in some circumstances

and worse off in others.

A supertaster is going to experience
at least three times

the burn from a chilli pepper
as another person.

Smoking and drinking have rather
unpleasant characteristics
to supertasters

and they don't do as much of that.

Bitter is going to be more intense

and bitter is something
we don't like,

so vegetables tend to be bitter,

supertasters don't eat
as many vegetables.

So what about Linda?

I hate to admit,
as a person working in this area,

that I am about as far away from
a supertaster as you can get.

And I know it's true,

my taste world is pastel,
nothing is terribly strong.

Never in my life have I perceived
anything to be too sweet,

most people can't say that.

So think again
of your favourite meal.

Bread and butter pudding
with a smooth, creamy custard.

That's just divine!

What you like,
you like for good reasons.

Partly, it's because of the
instincts you were born with.

Chocolate, I love chocolate.

Anything sweet.

That's my thing, really.
Sweet things.

Your tastes will be partly
what you ate as a child.

The earliest memory of food
I have in childhood is cake.

They could be partly
because of what your mother ate

before you were even born.

I love my chilli.

I like it so that I'm actually
breaking out a bit of a sweat.

I don't know why anyone would like
something that made them cry,
but I do.

But there is something
that shapes your taste

even more than what you're putting
into your mouths.

Molly Birnbaum's has had a lifetime
fascination with food.

In 2005, she was determined

that this interest was something
she wanted to pursue.

When I was in college, I fell in love
with food, with cooking,

with being by the stove,

with bringing people together
into my kitchen and feeding them.

I read more cookbooks than I did
textbooks, I was obsessed.

I knew that's what I wanted to be -
a chef.

Molly got her first job as a trainee
and was in her element.

I would get home,
in the wee hours of the morning,

smelling like veal stock and butter

and the fat from the deep fryer,

but I loved it.

I knew I wanted to spend the rest
of my life doing it.

She had found her purpose.

And was about to enrol in the
Culinary Institute of America.

This is what I wanted to do,

this was the first of many steps
towards becoming a chef,

something that I loved

and knew I wanted to spend
the rest of my life doing.

But then, one morning in August,
I went for a jog.

It was a drizzly morning, it was an
early morning and I was hit by a car.

Molly had multiple injuries,

including a broken pelvis
and a fractured skull.

Slowly, her body began to heal.

But the head trauma she had suffered
started to reveal other damage.

It was a month before I realised
that something else was wrong.

And that happened when my stepmother,
Cindy, baked an apple crisp.

It's one of my favourite desserts.

The scent of that dessert is just

one of the most beautiful things,
I think, that exists,

with the cinnamon and the butter
and the fruit.

But when she pulled it out
of the oven,

everyone in the room was oohing
and ahing over this smell

and she held it underneath my face
so I could inhale

and I could feel the steam in my
nose, which was warm and thick,

but there was no smell whatsoever.

In that moment, she realised
she had lost her sense of smell.

I could feel the texture
of the crisp berry topping,

I could feel the temperature,

and I could just feel them in my
mouth, this mush, sweet mush.

But everything that made it
apple crisp,

the flavour that I loved and
recognised and remembered, was gone.

It was just nothingness.

In fact, her sense of taste
was not damaged.

So she could taste sweet and sour,
for instance.

But because she couldn't smell,

there was no flavour to enjoy.

I relied on texture, on temperature,
on the visuals of food.

Two bowls of ice cream,
chocolate and vanilla,

without looking at the colour, they
would taste exactly the same to me.

Eating meat was flavourless,
texture blob,

some of it felt like
eating cardboard.

I put hot sauce on anything
and everything,

because it at least gave me tingles,

which was better than nothing.

But I was uninterested in all of it.

When Molly lost the ability
to make the connection

between the worlds of her senses

and the memories that had gone
with them, she felt lost.

I missed the smells of food

that my mother cooked
when I was a child.

I missed the smells of foods
and dishes, and places and people

that reminded me of my past,

because smell, I very quickly
realised, is so tied to our memory,

our emotional memories,

and I wondered who I would be

if I could no longer make
those memories for the future.

The simple truth is that what
most of us think of as taste

is, in fact, smell.

How taste and aroma come together
to become the flavours we enjoy

is at the forefront of research.

Your system of smell
is actually made of two parts.

Both operate whenever you eat,
say, a strawberry.

The first thing I do when I'm going
to eat this strawberry -

smell it, you get a wonderful
strawberry bouquet,

put it in my mouth.

When something is in your mouth
and you start chewing,

compounds called volatiles
are released.

I'm chewing...

..and swallowing forces the volatiles
up behind my palette

and into my nose.

The aroma that comes through
our nose is called orthonasal smell.

The smell system in your throat
and mouth - retronasal.

Finally, all these signals
come together in your brain.

It's a brain construction.

The brain sends it to an area
that also gets taste.

They interact and that's flavour.

The flavours we experience
are unique to us,

they are subjective,
we can't share them.

I can't experience a strawberry
through your senses,

only through my own.

So your sense of flavour
doesn't really happen

in your tongue or your nose,

but in your brain.

And that's why it connects
to your emotion and your memory.

When Molly lost that connection,
it was to Linda that she had turned.

You really have to understand
that this loss that Molly suffered

is devastating to your life.

And it happens...it makes people
miserable when it happens.

But Linda could only offer sympathy,

she had no remedy.

No-one was expecting what happened
to Molly some months later.

I was alone in the kitchen,

I had a bunch of fresh rosemary,
the herb, and I was chopping it.

Then, all of a sudden,
there was this scent.

And it just took over my entire
head, it took over my brain,

it was earthy and herby,

and, immediately, it reminded me
of a moment in my childhood

when I had gone horseback riding
out west

and there must have been
rosemary bushes.

But it just this incredibly
powerful rosemary scent.

And I remember I looked around,
I was just like,

"Oh, my God, it's back, it's here,
it's this!"

No-one's quite sure
how this happened.

But, somehow, the olfactory nerves

linking her smell to her brain
became active again.

And slowly, she started to recover
her smell and her memories.

Some of the first ones to come back
after rosemary

were ones that meant a lot to me.

Chocolate was one of the first
things that I could smell.

The sweet grape scent of wine,
I could smell.

Foods that I gained
most pleasure from

and they were related
to emotion, to my past,

to happy moments in my life.

I felt that my nose was doing the
good fight to get those back first.

Molly's experience of regaining
a rich and deep sense of taste

also underlies how, for each of us,

our sense of taste is connected
to our emotional experiences.

Emotions and memories
reinforce taste pathways

and connections in our brains.

Memories from childhood
are often the strongest.

I was about five or six, watching my
mum prepare stuffed vine leaves.

You could smell the lamb
wafting through the house

and sometimes, I used to go down and
sneak one when she wasn't looking.

There was five of us,
all sat round the table

and my mum used to put this big dish
in the middle

and we all used to have
a bit of Yorkshire pudding.

But for some of us, that pleasure
has started to control us.

I'm a bit of a chocoholic, you see.

So I enjoy chocolate,
milk chocolate,

chocolate with nuts in,
everything like that.

Once you eat it, you get these
brain waves and you think,

"Oh, this is really nice.
Go and get another one."

You know, "I want more of this."

It's quite pathetic, really,

that a grown woman, who can hold down
a job and look after two children,

can't go to bed if there's a bar
of chocolate in the fridge,

but that's just the way it is,
I can't.

Now, a growing number of researchers
are starting to wonder

if our understanding of taste
could have a practical use.

If we could use it
to trick ourselves

into liking less unhealthy foods.

And at the forefront of this work
is one substance - sugar.

In downtown Chicago, something
rather bizarre is happening.

It's taking place
in a gourmet kitchen.

The man behind the vision is
award-winning chef Homaro Cantu,

who is taking a rather unexpected
approach to food.

What we'll never get rid of

is the demand for sweets,
for fatty foods,

for foods that, you know,
degrade our health.

We need to make food that tastes
good, that's healthy for us,

that tastes like junk food.

When I grew up, we were homeless
for three years

and we went from homeless shelter
to homeless shelter.

And the food that we had there
was leftover junk food

and, even to this day, I still love
that food, it's delicious.

Inspired by his childhood memories,

Homaro has a mission -

to find a way of reducing
the amount of sugar we eat,

but without giving up sweet foods.

We're attacking just one small part
of the obesity epidemic,

we are just trying to get desserts
to be made without sugar

and we want them to taste better
than the real thing.

At the heart of his plan
is one small African berry.

Its potential to turn
sour into sweet

has been known about for centuries,

but there's a snag.

This is freeze-dried miracle berry.

This has a value
of probably around $400.

This little thing right here,

it's more expensive than truffles.

And this is where he has a secret.

What we do is we have
to turn it into this.

It's basically hundreds of times
cheaper than that.

But it does the same exact thing.

We add secret ingredients to it

and what we are going to do here
is just, you know,

tell you basically what this does.

The power of the berry powder is
that within minutes of eating it,

foods containing acid
will taste really sweet.

So first, you eat the powder, pause

and then any bitter citric
flavour you eat afterwards

will be transformed
into a sweet one.

I like to describe it like this -

not only is it the sweetest lemon
that you've ever had,

it's the tastiest lemon
you've ever had.

Each evening,
the miracle berry sensation

will be part of the guests'
experience.

But when they arrive,
they know nothing of this.

This is the real deal -
you are going to eat something

and then the flavours change
while it's in your mouth.

That's a whole new world
in gastronomy

that's never been tapped into.

It's like the real Willy Wonka
part of food.

You know, we've heard a lot about
Willy Wonka and science and food,

but that's all child play

compared to what happens when
you flavour trip at iNG Restaurant.

Tonight, the dessert
is course number six.

This is when the guests are
introduced to the star of the show -

the berry.

Basically, what we give
to the diners,

we'll just give them a little spoon
of this,

they will eat that,
it'll take about 60 seconds.

Once the lemon tastes sweet,

then they keep eating whatever
they're eating.

The dessert is sugar-free and bland,

but after eating the miracle
berry powder,

the hope is it will taste sweet
and interesting.

In the centre here, you have the
miracle berry in its powdered form.

What you do, you take the powder,
put all of it onto your tongue,

let it soak into your palate.
Once it's completely dissolved,

take a bite of the lemon
and if it tastes like lemonade,

that means it's working.

Once the powder is sitting
on the tongue,

it needs to be combined with acid.

Acid makes the sweet receptors
pucker up

and our perception of sweetness
explode.

It's sweeter now!

The berries contain a chemical,

a glycoprotein that's been called
miraculin.

This changes shape with acid,

enhancing the sweet receptors
so powerfully

that it drowns out the sour.

Oh, wow!

It just... Boom!
It just wakes you up.

Oh, that's nice.

This feels good,

it doesn't, like, roll me off
the back of the chair.

It's good! I like it.

Clearly, the berry gets a reaction,

but there's the problem of the gap.

You have to eat the powder
before the food.

If you combine them,

the science suggests
that you'll lose the effect.

The problem here is that you
have to eat this berry

and then you drink your soda
or you eat your cookie.

You know, that's for a small group
of people,

like, diabetics would do that.

But what about, you know,
a six-year-old kid?

They don't care what's going on
on their tongue,

they just want their cookie.

So what we're going to solve
is just that.

We're going to put the berry
in the cookie,

so, that way, when you eat it,
it tastes sweet,

but there's no glucose in this cookie
whatsoever.

Do you think you're going to be able
to do that? It is quite a difficult
thing to do, isn't it?

Uh... We've already done it.
We've done it on a small scale,

and now we need to take it
to the next level.

Just because I can make something
in a lab,

it doesn't mean that it's ready
for prime time.

So that's our next step.

This challenge of tricking
our taste,

luring us away from the seduction
of sugar, is being taken up.

Working in a quiet corner
of Florida,

Professor Harry Klee had come up
with his own plan.

A plan that was to have implications
that he could not have imagined.

He began his quest
not in the present,

but by delving back into our past.

It's kind of the reverse
of what we normally do in science.

We're going back 150 years
to recapture what was lost.

Harry was casting back
to a bygone age

to help with our contemporary
problem with eating.

There's no doubt there's a problem
with obesity in the developed world.

We are eating junk foods,

because we don't have foods that are
healthy for us that taste as good.

He started by looking at
the fruit we eat -

crops, he believes, are increasingly
grown for shelf life,

not for flavour.

He decided to focus on one plant.

There are people who are
growing up today

who have never tasted
a really good tomato,

that don't even know
what a good tomato is

and we need to fix that.

What inspired him to choose tomatoes

was a chance finding
in an old bookstore.

I found this reference in a very old
book from 1906 to these varieties

that kind of stirred my interest

and I said, "Well,
it'd be really neat

"if we could find these varieties,

"and grow them and see
what they taste like."

Harry set off on a massive
tomato trail.

He sent off to seed banks,

he even followed up on people's
personal preferences.

We got large, round, red ones,

we got oblong yellow ones,

we got green and black ones.

We knocked on every door we could

and checked every website

and collected several hundred
of these varieties

from all different sources
around the world.

Logistically, this has been
an absolute nightmare,

trying to grow these plants up.

Some of the plants do really well,
some of them do really badly,

some of the really good plants
give lousy fruit and you just wonder,

"What did people see in this
tomato that they actually saved it?"

After two of years of research,

they'd recovered 200 lost varieties.

They then set out to understand
the chemistry

that made the good ones
taste the way they did.

We knew that sugars were going
to be important

and we knew that acids
were going to be important

and we knew that the gaseous
compounds that you smell,

what we call volatiles,

some of them were going
to be important.

But we really didn't have an idea

which ones would really drive people
to like or dislike a tomato.

Harry's quest began.

Understanding the role of the sugars
and acids

would be the straightforward part.

Finding out whether the volatiles
would be important

and, if so, which, would be tricky.

As it turned out,
this knowledge of volatiles

was going to have implications
way beyond tomatoes.

But by the end of the process,

what Harry noticed was
the sheer wealth of detail

that he was collecting.

There was incredible variation
from tomato to tomato.

Far, far greater than we ever
expected for the different varieties.

We'd see a hundred or a thousand
fold differences sometimes

between different varieties,
in some of these chemicals.

Armed with this new knowledge,
Harry set up trials.

100 volunteers were recruited
and asked to rate the tomatoes.

Which ones did they like best

and what was it about the tomatoes
that they liked or disliked?

One of the things that we learned
early on was that

sweetness is a huge component
of a good-tasting tomato.

People like sweet.

Harry then looked at the chemistry
of these favoured tomatoes,

chosen largely
because of their sweetness.

And a pattern started to emerge.

What was really surprising to us

was that certain volatile chemicals

were actually making
those fruits taste sweeter

than the amount of sugar
that was in them.

What we found was
things that we smell

were enhancing the perception
on our tongue.

And that was unexpected.

In other words - our sense of smell
means that two tomatoes

with the same amount of sugar
could taste very different to us.

If one of those tomatoes
has more volatiles,

it could taste much sweeter.

These volatiles were intriguing.

I have a few of them right here.

This first one - geranial.

To me, it smells like flowers,
perfume...

It's not a bad smell, it doesn't
smell anything like a tomato.

It doesn't smell sweet.

One of the volatiles that was a huge
surprise was this one here -

isovaleric acid.

This is a really nasty chemical,

most of the people in my lab
describe it

as the smell of dirty socks
or a locker room.

It's really terrible

and you smell this
and you can think of...

..men running around naked
with their underwear

and yet, this turns out to be
a really important chemical

that's contributing
to the perception of sweetness.

Not a single one of them
smells like tomato,

not a single one of them
particularly smells...

anything like a food product even

and yet, it's the combination
of all of those chemicals

that make the tomato smell
the way it smells

and make it taste the way it tastes.

Harry now knew which
of the ancient, heirloom tomatoes
were the sweet ones.

He knew they were the ones
with extra volatiles.

But they were really hard to grow.

What he wondered was,

could he cross-breed
these old, sweet favourites

with the hardy modern tomato
to get the best of both worlds?

Can we take those varieties
that people really like

but are just horrible to grow?

Can we very quickly turn those into
something that still tastes great,

but actually has some performance
of a modern variety.

Two years later, he had the result.

It was hardy
and, he thought, delicious.

Now, it was all down
to the consumers.

Much to our shock, people said,

"Hey, we like these just as much.

"They're just as good
as the heirlooms."

And we're thinking, "This is great!"

Because these things make
five times as much fruit

and the fruit are so much healthier

and the plants are so much healthier
and they taste just as good.

But now, Harry's success with
tomatoes gave him another idea.

Something that he had never
set out to do.

What if he could take
these volatiles,

nature's natural sweeteners,

and use them in cakes or desserts?

The next logical step is,

"Well, what happens if we take a food

"that has sugar, that's desirable
because it's sweet,

"what if we take some
of that sugar out

"and replace it with these volatiles

"that synergize to make it taste
just as sweet,

"with less sugar in it?"

And if we do that,

then we have the potential
to take foods and improve them.

Harry's work on tomatoes could lead

to a natural, calorie-free,
sweet alternative to sugar.

It's a bold idea,
but he has been developing it

with the most pre-eminent scientist
in taste.

We found a lot of volatiles

that were adding to the sweetness
of the tomato

and had nothing to do with the sugar
content of the tomato.

So, all of a sudden,
we've got volatiles creating sweet.

Together, they've been
preparing tests

to see how they can apply this
to other sugary foods.

So far, it looks like
it's going to work.

We have to do all the experiments
indicated -

take it out, put it in something
else and see if it has an effect.

But the truth is,

I think the chances are that
this is going to work broadly

in a lot of different foods
and beverages.

It's possible that
what started out as a mission

to promote the humble tomato,

could actually help our troubled
relationship with sugar.

In theory, the things
that we're doing

with the volatile enhancement
of sweetness

could apply to fruit juices,
could apply to desserts,

could apply to almost any food
where you are combining products.

There's no reason that we can't make
something taste just as sweet

with less sugar in it.

You could see that very soon.

That could impact some of the
products that are sold today.

Our brains tell us to eat sugar,

they tell us to go after sweet.

It's hardwired in the brain.

Now, can you fool the brain?

Can you provide it with sweet
that's safe and that isn't sugar?

I think that's the Holy Grail.

Looking for different ways
to trick our sense of taste

has become an active area
of scientific research.

Although the very idea
of manipulating what we eat,

even to make us healthy,
raises obvious concerns.

But even if it can be done,

there's another hurdle to cross

and that leads us
into a different science -

the science of us.

It's 6am at the Smithsonian Zoo,
in Washington.

And time for breakfast.

Preparing and delivering
the right meal for each animal

for the day ahead.

Good morning, lion, tiger.
Your diets have been delivered.

Have a good day.

Nutrition to wolf keeper.
Your diets have been dropped off.

Have a good day.

Animal scientist and nutritionist
Michael Power

knows exactly what each animal
receives.

Animals with their food preference

have evolved over long periods
of time.

When you bring animals
into captivity,

you have a responsibility to them.

We have to give them
a selection and choice,

while we also make sure
the nutrition is right.

This means they have
to put together a diet

that resembles what
they've evolved to eat.

We too were once
on the same evolutionary path,

but we've branched off.

We, as a species, have actually
changed the fact

that we're capable of manipulating
our environment and changing things

and actually, making our external
environment more like we want it,

as opposed to the way it is.

We know we've evolved to prefer
high-fat and high-sugar foods,

but, in nature, they never occur
together in one food.

Bananas are high in sugar
but are fat-free,

avocadoes are the opposite.

We can now put those all together
in the same thing.

You come up with a candy bar

with, like, salty nuts in it
and nice fat in there

and lots of sugar and chocolate
all over and everything.

We only have to think about it.
We simply say,

"Well, what do we want?"
That's all we have to worry about.

What do we want
and what's easy to get.

Also, the speed at which we have
changed our environment

means that we have not evolved
to deal with the endless supply.

Our ancestors never needed
to know when to stop,

because there were always times
when food was scarce.

We never evolved a protective
barrier against too much,

because there never was
too much before.

The external environment
put the barrier on

and now, though, we can produce
too much and we love it.

And so would all the animals
in the zoo.

Given a chance,
they'd choose a diet like ours,

only the zoo doesn't let them.

In a sense, what you look at is
the animals in the zoo are probably
in general getting a better diet

than most of the people
who come to watch them.

And this is the puzzle.

Why do we willingly eat too much
of the food we know is bad for us?

There's been years and years
of study, trying to figure out

what controls our appetite,
how can we control what we eat.

And all of it basically revolves
around looking at it

from a nutritional basis.

The problem with human beings is that

that's not what food
means only to us any more.

We eat in meals,
we eat with other people.

So now, a meal, sitting and eating,

has more to do than with just
the food, with just the nutrition,

it has to do with
the whole social context.

Very, very different scenario
from what a chimpanzee does

or an orang-utan does
or a gorilla does.

It could be a pleasurable one,

it could have politics involved,
it could have sex involved.

It could be dating,
it could be meeting new people.

The business lunch.

A meal is something we use
to accomplish purposes

besides filling our bellies.

We are the ultimate social animal.

It's what has made us
the dominant species.

Yet, this asset comes
with a potential weakness.

If the social group has come to be
eating too much of the wrong food,

it's hard to be the one who doesn't.

If the people in your social group
are eating a certain kind of food,

well, that's the kind of food that
you're also going to want to eat.

So if you're determined to diet,
it makes it difficult for you.

You have one part of your biology,
the social part,

telling you to go this way

and the part that's listened to maybe
the nutritionist and the scientist

saying, "No, no, no, I should be
eating this for my health."

And then, your stomach is trying to
tell you whether it's full or not,

but that isn't necessarily
what you're listening to,

depending on the circumstances.

If you're sitting there happily
chatting away

or everybody else orders dessert,

you say, "Well, yes, I could eat
a little bit more.

"Yes, I'll have that dessert too."

We all know that meals
are about much more than food.

You kind of just keep going.

As long as there's conversation,
you're still eating

and that will probably be more
than you actually need.

If food was just about nutrition,

there wouldn't be so many
overweight people.

But, to me, it's about feeling safe

and feeling needed and wanted.

SHE CHUCKLES

It gives you a nice sensation
that you're looking after them.

I've put on about two stone in the
last year since I met my boyfriend,

because we both love food.

You can justify it
to yourself better

if you've got someone else sitting,
doing it there with you.

It's an easy trap to fall into.

I don't want my children to grow up

with an attitude to food
like I've got,

and I will do everything in my power
to make sure that they're healthy.

We're pulled in different directions

between our desire to be healthy

and our basic human nature.

With our understanding of taste,

we may have created a technology
that can help us deal with this.

We're a clever species,
we got ourselves into this mess.

It's possible that there are
technological ways out of it,

but there is decent evidence
out there that says

that just because you give someone
a sweet taste with no calories,

that may actually increase
their food intake.

It may not actually allow them
to eat less food.

So it's a very difficult,
a very difficult problem.

In Florida, the scientists think

their technology can make
some contribution,

if we use it wisely.

Humans just, by our genetic make-up,

like sweet and there's no way
around that.

So let's give sweet in a package

that's a little healthier for you.

I don't think that
that's a bad thing.

I think it's a very good thing.

I think what we're doing
is applying knowledge that we got,

that we didn't expect to find,

this was serendipitous, but let's
take it and use it to our advantage,

to improve the human diet.

I see no problem at all with that,

I'm very excited about that.

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