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Almost two-thirds (about 66%) of U.S. adults age 20 or older are overweight -- about 62% of women and around 71% of men. Nearly one-third (about 31%) of American adults are so overweight that they are considered obese. |
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For years I wondered why I was fat. I lost weight, gained it back,
and lost it again – over and over and over. I owned suits in every
size. As a former commissioner of the FDA
(the US Food and Drug Administration), surely I should have the answer
to my problems. Yet food held remarkable sway over my behaviour.
The
latest science seemed to suggest being overweight was my destiny. I was
fat because my body's "thermostat" was set high. If I lost weight, my
body would try to get it back, slowing down my metabolism till I
returned to my predetermined set point.
But this theory didn't
explain why so many people, in the US and UK in particular, were
getting significantly fatter. For thousands of years, human body weight
had stayed remarkably stable. Millions of calories passed through our
bodies, yet with rare exceptions our weight neither rose nor fell.
A perfect biological system seemed to be at work. Then, in the 80s,
something changed.
Three decades ago, fewer than one Briton in 10 was obese. One in four is today. It is projected that by 2050,
Britain could be a "mainly obese society". Similar, and even more
pronounced, changes were taking place in the US, where researchers
found that not only were Americans entering their adult years at a
significantly higher weight but, while on average everyone was getting
heavier, the heaviest people were gaining disproportionately more
weight than others. The spread between those at the upper end of the
weight curve and those at the lower end was widening. Overweight people
were becoming more overweight.
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During the past 20 years there has been a dramatic increase in obesity in the United States. |
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What had happened to add so many
millions of pounds to so many millions of people? Certainly food had
become more readily available, with larger portion sizes, more chain
restaurants and a culture that promotes out-of-home eating. But having
food available doesn't mean we have to eat it. What has been driving us
to overeat?
It is certainly not a want born of fear of food
shortages. Nor is it a want rooted in hunger or the love of exceptional
food. We know, too, that overeating is not the sole province of those
who are overweight. Even people who remain slim often feel embattled by
their drive for food. It takes serious restraint to resist an almost
overpowering urge to eat. Yet many, including doctors and healthcare
professionals, still think that weight gainers merely lack willpower,
or perhaps self-esteem. Few have recognised the distinctive pattern of
overeating that has become widespread in the population. No one has
seen loss of control as its most defining characteristic.
"Higher
sugar, fat and salt make you want to eat more." I had read this in
scientific literature, and heard it in conversations with
neuroscientists and psychologists. But here was a leading food
designer, a Henry Ford of mass-produced food, revealing how his industry operates. To protect
his business, he did not want to be identified, but he was remarkably
candid, explaining how the food industry creates dishes to hit what he
called the "three points of the compass".
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The ultra-high levels of fat make food easier to chew, whereby faster bypasses normal feelings of satiation. People addicted to the such foods tend to gorge. |
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Sugar, fat and salt
make a food compelling. They stimulate neurons, cells that trigger the
brain's reward system and release dopamine, a chemical that motivates
our behaviour and makes us want to eat more. Many of us have what's
called a "bliss point", at which we get the greatest pleasure from
sugar, fat or salt. Combined in the right way, they make a product
indulgent, high in "hedonic value".
During the past two decades,
there has been an explosion in our ability to access and afford what
scientists call highly "palatable" foods. By palatability, they don't
just mean it tastes good: they are referring primarily to its capacity
to stimulate the appetite. Restaurants sit at the epicentre of this
explosion, along with an ever-expanding range of dishes that hit these
three compass points. Sugar, fat and salt are either loaded into a core
ingredient (such as meat, vegetables, potato or bread), layered on top
of it, or both. Deep-fried tortilla chips are an example of loading –
the fat is contained in the chip itself. When it is smothered in
cheese, sour cream and sauce, that's layering.
It is not just
that fast food chains serve food with more fat, sugar and salt, or that
intensive processing virtually eliminates our need to chew before
swallowing, or that snacks are now available at any time. It is the
combination of all that, and more.
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Combined in the right way, sugar, fat and salt act like a drug.
They stimulate neurons, cells that trigger the brain's reward system and release dopamine, a chemical that makes us want to eat more. |
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Take Kentucky Fried Chicken.
My source called it "a premier example" of putting more fat on our
plate. KFC's approach to battering its food results in "an optimised
fat pick-up system". With its flour, salt, MSG, maltodextrin, sugar,
corn syrup and spice, the fried coating imparts flavour that touches on
all three points of the compass while giving the consumer the
perception of a bargain – a big plate of food at a good price.
Initially,
KFC meals were built around a whole chicken, with a pick-up surface
that contained "an enormous amount of breading, crispiness and
brownness on the surface. That makes the chicken look like more and
gives it this wonderful oily flavour." Over time, the company began to
realise there was less meat in a chicken nugget compared with a whole
chicken, and a greater percentage of fried batter. But the real
breakthrough was popcorn chicken. "The smaller the piece of meat, the
greater the percentage of fat pick-up," said the food designer. "Now,
we have lots of pieces of a cheaper part of the chicken." The product
has been "optimised on every dimension", with the fat, sugar and salt
combining with the perception of good value virtually to guarantee
consumer appeal.
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The original Whopper was already explosively rich in fat, sugar and salt, even before the addition of more beef, extra cheese, fried onion rings, and a layer of bacon. Perhaps they should change the name to "The Heart Stopper". |
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He walked me through some offerings at other popular food chains. Burger King's Whopper
touched on the three points of the compass – then was altered for
further effect. In its first, stripped-down form, the burger was
explosively rich in fat, sugar and salt. Then the chain began adding
more beef, extra cheese or a layer of bacon.
McDonald's
broke new ground in another way – by making food available on a whim.
"The great growth has been the snacking occasion. You get hungry, you
want something, your mind pushes off the reality of what you ought to
eat, and you end up picking up a hamburger and a giant soda or french
fries."
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A McDonald's Double Sausage McMuffin contains 575 calories, which is 28% of the RDV. The popular sandwich also contains 36 grams of fat- a whopping 55% of the RDV! |
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Next they introduced a high-fat, high-salt morning meal.
"They took what they learned from the core lunch and dinner menu, and
applied it to breakfast. The sausage McMuffin and the egg McMuffin are
stand-ins for the hamburger. In effect, you are eating a morning
hamburger."
This kind of food disappears down our throats so
quickly after the first bite that it readily overrides the body's
signals that should tell us, "I'm full." The food designer offered
coleslaw as an example. When its ingredients are chopped roughly, it
requires time and energy to chew. But when cabbage and carrots are
softened in a high-fat dressing, coleslaw ceases to be "something with
a lot of innate ability to satisfy".
This isn't to say that the
food industry wants us to stop chewing altogether. It knows we want to
eat a doughnut, not drink it. "The key is to create foods with just
enough chew – but not too much. When you're eating these things, you've
had 500, 600, 800, 900 calories before you know it." Foods that slip
down don't leave us with a sense of being well fed. In making food
disappear so swiftly, fat and sugar only leave us wanting more.
According to food consultant Gail Vance Civille, of management consultants Sensory Spectrum,
fat is crucial to this process of lubrication, ensuring that a product
melts in the mouth. In the past, she says, Americans typically chewed
food up to 25 times before it was swallowed; now the average American
chews 10 times. "If I have fat in there, I just chew it up and whoosh!
Away it goes," she says. "You have a 'quick getaway', a quick melt."
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A deep fried Snickers bar, another popular American treat. |
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The Snickers
bar, Civille says, is "extraordinarily well engineered". Unlike many
products whose nuts become annoyingly lodged between your teeth, the
genius of Snickers is that as we chew, the sugar dissolves, the fat
melts and the caramel picks up the peanut pieces, so the entire candy
is carried out of the mouth at the same time. "You're not getting a
build-up of stuff in your mouth."
Kettle chips
are another success story. Made of sugar-rich russet potatoes, they
have a slightly bitter background note and brown irregularly, which
gives them a complex flavour. High levels of fat generate easy
mouth-melt, and surface variations add a level of interest beyond that
found in mass-produced chips. Heightened complexity is the key to
modern food design.
Not so many decades ago, a single flavour of
ice-cream was a special treat. Our options ran to vanilla, chocolate
and strawberry – and when we could buy all three in a single carton, we
saw that as a great innovation. Now ice-cream has countless flavours
and varieties; it comes mixed with M&M's or topped with caramel sauce.
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The complexity of the stimulus increases its association to a reward. Elements of that complexity include tastes that are familiar and well liked, and the learning associated with having had a pleasurable experience with the same food in the past. |
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When
layers of complexity are built into food, the effect becomes more
powerful. Sweetness alone does not account for the full impact of a
fizzy drink – its temperature and tingle, resulting from the
stimulation of the trigeminal nerve by carbonation and acid, are essential contributors as well.
"The complexity of the stimulus increases its association to a reward," says Gaetano Di Chiara, an expert in neuroscience and pharmacology at the University of Cagliari in Italy. Elements of
that complexity include tastes that are familiar and well liked,
especially if not always readily available, and the learning associated
with having had a pleasurable experience with the same food in the past.
Take
a bowl of M&M's. If I've eaten them in the past, I'm stimulated by
the sight of them, because I know they'll be rewarding. I eat one, and
experience that reward. The visual cue gains power and stimulates the
urge we call "wanting". The more potent and complex foods become, the
greater the rewards they may offer. The excitement in the brain
increases our desire for further stimulation.
In theory there's a
limit to how much stimulation rewarding foods can generate. We are
supposed to habituate – to neuroadapt. When Di Chiara gave animals a
cheesy snack called Fonzies, the levels of dopamine in their brains
increased. Over time, habituation set in, dopamine levels fell and the
food lost its capacity to activate their behaviour.
But if the
stimulus is powerful enough, novel enough or administered
intermittently enough, the brain may not curb its dopamine response.
Desire remains high. We see this with cocaine use, which does not
result in habituation. Hyperpalatable foods alter the landscape of the
brain in much the same way.
I asked Di Chiara to study what
happens after an animal is repeatedly exposed to a high-sugar, high-fat
chocolate drink. When he'd completed his experiment, he sent me an
email with "Important results!!!!" in the subject line. He had shown
that dopamine response did not diminish over time with the chocolate drink. There was no habituation.
Novelty
also impedes habituation, and intermittency is another driver. Give an
animal enough sugar-laden food, withdraw it for the right amount of
time, then provide it again in sufficient quantities, and dopamine
levels may not diminish.
"The industry
has jacked up what works for it. The learning is
evolutionary.
Practical experience has been its guide – it does not
need lab rats when it can try out its ideas on humans. Its
decision-makers do not have to analyse human brain circuitry to
discover what sells." |
There's still a lot we don't know about
the relationship between the dopamine-driven motivational system and
our behaviour in the presence of rewarding foods. But we do know that
foods high in sugar, fat and salt are altering the biological circuitry
of our brains. We have scientific techniques that demonstrate how
these foods – and the cues associated with them – change the
connections between the neural circuits and their response patterns.
Rewarding
foods are rewiring our brains. As they do, we become more sensitive to
the cues that lead us to anticipate the reward. In that circularity
lies a trap: we can no longer control our responses to highly palatable
foods because our brains have been changed by the foods we eat.
I
wanted to know how much the industry understood about how the food we
eat affects us; about what I have termed "conditioned hypereating" –
"conditioned" because it becomes an automatic response to widely
available food, "hyper" because the eating is excessive and hard to
control. I turned to Joseph Stiglitz, a Nobel laureate in economics.
"Does the industry know that what it feeds us gets us to eat more?" I asked.
"The industry
has jacked up what works for it," Stiglitz said. "The learning is
evolutionary." Practical experience has been its guide – it does not
need lab rats when it can try out its ideas on humans. Its
decision-makers do not have to analyse human brain circuitry to
discover what sells.
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This tasty treat contains 18 tablespoons of sugar- and that's for the smaller sized serving. |
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A venture capitalist who knows the business intimately cited Starbucks
as a company that has recognised and responded brilliantly to a
cultural need. The caffeine and sugar in the coffee, with their
energising effects, are certainly part of the equation, but the chain
also offers something much more primal. "It's about warm milk and a
bottle," he says. "One of my colleagues said, 'If I could put a nipple
on it, I'd be a multimillionaire'."
But it was thinking creatively about how to attract more consumers that led Starbucks to the Frappuccino,
the venture capitalist told me. Although its stores were crowded early
in the day, by afternoon "they were so empty you could roll a bowling
ball through them". The creation of a rich, sweet and comforting
milkshake-like concoction utterly transformed the business. A Starbucks
Strawberries & Crème Frappuccino comes with whipped cream and 18
teaspoons of sugar: all in all, this "drink" contains more calories
than a personal-size pepperoni pizza, and more sweetness than six
scoops of ice-cream. By encouraging us to consider any occasion for
food an opportunity for pleasure and reward, the industry invites us to
indulge a lot more often.
Starbucks learned a basic lesson: make
enticing food easily and constantly available, keep it novel, and
people will keep coming back for more. With food available in almost
any setting, "the number of cues, the number of opportunities" to eat
have increased, while the barriers to consumption have fallen, says David Mela, senior scientist of weight management at the Unilever Health Institute. "The environmental stimulus has changed."
Of
course, when food is offered to us, we're not obliged to eat it. When
it's on the menu, we don't have to order it. But this takes more than
willpower. As an individual, you can practise eating the food you want
in a controlled way. As a society, we can identify the forces that
drive overeating and find ways to diminish their power. That's what
happened with the tobacco industry: attitudes to smoking shifted.
Similar changes could be brought about in our attitudes to food – by
making it mandatory for restaurants to list calorie counts on their
menus; by clear labelling on food products; by monitoring food
marketing. But until then few of us are immune to the ubiquitous
presence of food, the incessant marketing and the cultural assumption
that it's acceptable to eat anywhere, at any time.
Call it the
"taco chip challenge" – the challenge of controlled eating in the face
of constant food availability. "Forty years ago, you might face the
social equivalent of that taco chip challenge once a month. Now you
face it every single day," Mela said. "Every single day and every
single place you go, those foods are there, those foods are cheap,
those foods are readily available for you to engage in. There is
constant, constant opportunity."
This is an edited extract from The End Of Overeating: Taking Control Of Our Insatiable Appetite, by David A Kessler, published by Penguin on 1 April at £9.99. To order a copy with free UK p&p, go to guardian.co.uk/bookshop.
The Guardian.uk