Very interesting, here is a repeat post I made a couple of days ago which
discusses another aspect of our food/eating culture which affects our
overeating:
The perception effect of variety described is one thing some
thinks help a low carb diet work,ie. less variety in it
curbs hunger more quickly.
CONCORD, N.H. (AP) - Ed Glomb admits he gets a little
carried away when faced with the more than 150 all-you-can-
eat options on the Red Apple Buffet's Italian-American-Chinese-
Japanese menu.
"Everybody has a tendency to eat with their eyes," he
said recently, adding that he'd already eaten soup,
shrimp and crab legs - starters to be followed by
roast beef, potatoes and dessert. "It's a little bit
of this and a little bit of that."
But Glomb's tendency to pile it on at his favorite
restaurant - and his rotund size - may have as much to
do with the number of choices on the buffet table as
the unlimited portions being offered.
Call it the "salad bar effect." Studies suggest that
variety increases consumption. With monotonous meals,
people eat until they are full. Add variety, even
something as subtle as different shapes of pasta, and
they eat more.
Studies dating back to the 1960s have shown that
variety can increase calorie consumption an average of
25 percent, according to Megan McCrory, a nutrition
scientist at Tufts University.
That has some researchers grappling with the global
obesity epidemic considering what role an often
dizzying array of food choices might play in expanding
the collective waistline.
"Nutritionists have been wrong. We've been telling you
for years variety is important, but it's that variety
that really helps to make you fat," said Judith S.
Stern, vice president of the American Obesity
Association.
The science may not be familiar to most people, but
its effects probably are.
It plays out "in restaurants when you're really
stuffed to the brim and you just can't have
another bite," McCrory said. "Then the waiter
brings around the dessert cart. ... There's always
room for dessert."
Blame it on so-called sensory specific satiety, a
mental process that makes food taste better at first
but progressively less interesting as a person
continues to eat it. Switch to a new food and, even if
the person is full, it will be appealing.
Marketers know this. Coca-Cola sells nearly 400
different drinks, Frito-Lay offers about 150 different
chips and pretzels in the United States alone, and
Campbell's produces 170 soups.
"If all you have is chicken soup, you probably won't
eat soup night after night," said John Faulkner, a
spokesman for the Campbell Soup Company. "But the more
varieties you have, the more of it you'll eat."
Barbara Rolls, a professor of nutrition at Penn State
University, said this dietary trigger dates back to
humanity's early days, when survival was best served
by a natural inclination to eat a variety of foods.
"It encourages you to switch from food to food," she
said. "As omnivores with a variety of nutrient
requirements, we need to switch from food to food and
take in a lot of different nutrients. This is actually
an adaptive response."
Most researchers agree on the science behind sensory
specific satiety. Where they differ is on how it
affects overall eating patterns and how significantly
it contributes to obesity.
Rolls and McCrory, two of the leading researchers in
the field, think it does.
"There's so much variety that especially when the
variety tastes really good we're more apt to go ahead
and eat it, especially when it's everywhere you turn,"
McCrory said.
The problem isn't just that people seek variety, but
also that the foods they are eating are high in
calories, Rolls said. People learn as children to
prefer high-calorie foods because they satisfy
cravings quickly.
Rolls said it's a prescription for obesity - easy
access to a growing variety of high-calorie foods
paired with a natural inclination to eat more of them.
And though obesity long has been considered an
American problem, the rest of the world is catching
up. McCrory thinks that might be due to a greater
variety of foods becoming available in other nations,
especially calorie-dense items.
Availability of such foods overseas has increased
dramatically. Since 1989, U.S. exports of snack foods
have quadrupled to more than $1.5 billion last year,
according to the U.S. Department of Commerce.
An influx of variety has had a dramatic effect on the
people of the Solomon Islands in the South Pacific,
said Gary Miller, a professor of nutrition and obesity
at Wake Forest University.
He said 30 year ago the islanders' diet was limited
mostly to what could be produced locally. Trade has
since introduced a torrent of variety, especially calorie-
dense foods previously absent from this nation of
340,000 people.
The country now has one of the highest obesity rates
in the world.
Richard Mattes, a nutrition professor at Purdue
University, said it isn't that simple. Though he
agrees that variety prompts people to eat more, he
said studies have yet to prove the effect of sensory
specific satiety lasts beyond a particular meal.
In fact, some studies suggest that after a meal of
variety-induced excess, people compensate and eat
less later, he said.
But Dr. Terry Maratos-Flier, head of obesity research
at the Joslin Diabetes Center in Boston, said that's
generally only true with lean people. Overweight
people - roughly two-thirds of Americans - often don't
compensate.
Mattes also questions whether variety is responsible
for the global spread of obesity. He said that more
likely is due to sedentary lifestyles and an overall
increased consumption of calorie-dense foods.
"Has variety really increased over say the last 20, 25
years? Yes, there have been many new products
introduced into the market place. But that's not the
measure," he said.
"The measure is what are the number of unique foods
Americans ate during the 1970s and what is the number
of unique foods Americans are eating today?"
Maratos-Flier thinks people are eating a greater
variety, but not because there are more foods. She
said low costs and ease of transportation have made it
easier for more people to eat more food, and more
types of food.
Consumers are surrounded by a staggering array of
food: The typical American grocer has 35,000 products,
up from 10,000 in 1983, according to Walter Heller,
research director for Progressive Grocer magazine.
During the 1930s, it was around 800 items.
Researchers don't think food variety alone dooms
people to being overweight, but it doesn't hurt.
Sensory specific satiety can help people lose weight.
Obesity experts agree that the most successful diets
are the most restrictive - the more people eat of one
food, the less they want it. As a result, they eat
less and lose weight.
"Even if you went on a doughnut diet, if that's all
you had you would undoubtedly lose weight because of
monotony and lack of variety. Obviously that's not a
good idea," Rolls said.
But since human nature is working against it, such
diets also are the hardest to stick with.
Giving in to the urge for variety also can be good, as
long as the food choices are sound. Filling up on a
variety of low-calorie foods leaves less room for
calorie dense-foods.
"You can't get rid of variety. People want 100
channels. They wants thousands of CDs and books.
There's no policy that's going to get rid of variety
in foods," Maratos-Flier said. "What you need is
education" about good food choices.
As Glomb's wife has found, human nature is hard to
fight. The urge doesn't diminish even in the face of
absurd variety.
"This is good but it would be nice to have something
different for a change," Marilynn Glomb said after
mulling the options at the Red Apple Buffet, where the
Merrimack couple eats twice a week. "It's the same
thing every time you come."
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On the Web:
Tufts University Human Nutrition Research Center on
Aging:
hnrc.tufts.eduhnrc.tufts.eduOpen ↗
Penn State University: psu.edupsu.eduOpen ↗
American Obesity Association: obesity.orgobesity.orgOpen ↗
