targeted in fight against obesity
Low-fat, low-cal, low-carb.
Atkins, South Beach, The Zone. Food
fads may be distracting attention
from something more insidiously
piling on pounds: beverages.
One of every five calories in the
American diet is liquid. The
nation's single biggest "food" is
soda, and nutrition experts have
long demonized it.
Now they are escalating the
In reports to be published in
science journals this week, two
groups of researchers hope to add
evidence to the theory that soda and
other sugar-sweetened drinks don't
just go hand-in-hand with obesity,
but actually cause it. Not that
these drinks are the only cause -
genetics, exercise and other factors
are involved - but that they are one
cause, perhaps the leading cause.
A small point? In reality,
proving this would be a scientific
leap that could help make the case
for higher taxes on soda,
restrictions on how and where it is
sold - maybe even a surgeon
general's warning on labels.
"We've done it with cigarettes,"
said one scientist advocating this,
Barry Popkin at the University of
North Carolina in Chapel Hill.
Comparing soda and obesity to
tobacco and lung cancer is a
baseless crusade, industry spokesmen
"I think that's laughable," said
Richard Adamson, a senior science
consultant to the American Beverage
Association. Lack of exercise and
poor eating habits are far bigger
contributors to America's weight
woes, he said.
"The science is being stretched,"
said Adam Drewnowski, director of
nutritional sciences at the
University of Washington in Seattle.
He owns stock in beverage companies
and has done extensive research in
the field, much of it financed by
industry but also some by
However, those making the case
against soda include some of the
nation's top obesity researchers at
prestigious institutions like
Harvard and Yale.
"There are many different lines
of evidence, just like smoking,"
said Dr. David Ludwig, a Harvard
pediatrician who wants a "fat tax"
on fast food and drinks.
Beverage companies seem worried.
Some are making sodas "healthier" by
adding calcium and vitamins, and
pushing fortified but sugary sports
drinks in schools that ban soda.
This could help them duck any
regulations aimed at "empty calorie"
drinks, said Jennifer Follett, a
USDA nutritionist at the University
of California in Davis.
"Even defining 'milk' is getting
tough these days," with so many
flavored varieties and sweetened
liquid yogurts, she complained. "It
tastes like you're sucking on ice
Proving that something causes
disease is not easy. It took decades
with tobacco, asbestos and other
substances now known to cause
cancer, and met strong industry
opposition. It would be especially
tough for a disease as complex as
Diet is hard to study. Most
people drink at least some sweetened
beverages and also get calories from
other drinks like milk and orange
juice, diluting the strength of any
observations about excess weight
from soda alone.
Children are growing and gaining
weight naturally, "so we have this
added complication" of trying to
determine how much extra gain is due
to sweet-drink consumption, said
Alison Field, a nutrition expert at
Hospital in Boston.
"Given these caveats, it's
amazing the association we do see,"
She was among hundreds of
scientists who packed a "mock trial"
of such drinks at a conference of
the Obesity Society last year in
Vancouver, British Columbia.
Here is the "food police"
indictment of soda and its
sugar-sweetened co-conspirators. You
be the judge:
-Count One: Guilt by association.
Soft drink consumption rose more
than 60 percent among adults and
more than doubled in kids from
1977-97. The prevalence of obesity
roughly doubled in that time.
Scientists say these parallel trends
are one criterion for proving
Numerous studies link sugary
drink consumption with weight gain
or obesity. One by Ludwig of 548
Massachusetts schoolchildren found
that for each additional sweet drink
consumed per day, the odds of
obesity increased 60 percent.
Another at Harvard of 51,603
nurses compared two periods, 1991-95
and 1995-99, and found that women
whose soda drinking increased had
bigger rises in body-mass index than
those who drank less or the same.
-Count Two: Physical evidence.
Biologically, the calories from
sugar-sweetened beverages are
fundamentally different in the body
than those from food.
The main sweetener in soda -
high-fructose corn syrup - can
increase fats in the blood called
triglycerides, which raises the risk
of heart problems, diabetes and
other health woes.
This sweetener also doesn't spur
production of insulin to make the
body "process" calories, nor does it
spur leptin, a substance that tamps
down appetite, as other
carbohydrates do, explained Dr.
George Bray of the Pennington
Biomedical Research Center in Baton
"There's a lack of fullness or
satiety. The brain just seems to add
it on," said Dr. Louis Aronne, a
Weill-Cornell Medical College doctor
who is president of the Obesity
Two studies by Penn State
nutritionist Barbara Rolls
illustrate this. One gave 14 men
lemonade, diet lemonade, water or no
drink and then allowed them to eat
as much as they wanted at lunch.
Food intake didn't vary, no matter
what they drank.
The second study gave 44 women
water, diet soda, regular soda,
orange juice, milk or no drink
before lunch. Total intake was 104
calories greater for those given
caloric beverages than those given
diet soda, water or no beverage.
Caloric drinks didn't help women
feel any fuller either.
Then there is the "jelly bean
study." Purdue University
researchers gave 15 men and women
450 calories a day of either soda or
jelly beans for a month, then
switched them for the next month and
kept track of total consumption.
Candy eaters ate less food to
compensate for the extra calories.
Soda drinkers did not.
-Count Three: Bad influence on
Sugar-sweetened beverages affect
the intake of other foods, such as
lowering milk consumption. Popkin
contends they also may be
psychological triggers of poor
eating habits and cravings for fast
He examined dietary patterns of
9,500 American adults in a federal
study from 1999-2002. Those who
drank healthier beverages - water,
low-fat milk, unsweetened coffee or
tea - were more likely to eat
vegetables and less likely to eat
consumption was doubled if they were
high soda consumers and vegetable
consumption was halved," he said.
Harvard epidemiologist Eric Rimm
saw a similar effect in a different
federally funded study of more than
5,000 young adults. With high soda
consumption, "you see this pattern
of less healthy intake across the
board," he said at the obesity
-Count Four: Consistency of
Many studies of different types
link sugary drinks and weight gain
or obesity. Some even show a
"dose-response" relationship - as
consumption rises, so does weight.
Collectively, they meet many
criteria for proving cause and
effect, Dr. William Dietz, director
of nutrition at the federal Centers
for Disease Control and Prevention
wrote in an editorial accompanying a
study in February's Journal of
In rebuttal, Adamson, the
beverage industry spokesman, sees no
such consistency. He cites a 2004
Harvard study of more than 10,000
children and teens. Consumption of
sugar-added beverages was tied to
body-mass index gain in boys but not
girls, a gender difference that
warrants a "jaundiced eye" to claims
that soda is at fault, he said.
He also points to a Harvard study
finding no link between weight
changes and soda consumption among
1,345 North Dakota children ages 2
to 5 - a group that arguably drinks
far less soda than teens and adults.
"Whatever association there is
doesn't seem to be large," said
Richard Forshee, deputy director of
the Center for Food, Nutrition and
Agriculture Policy at the University
of Maryland who has received
research funding from the beverage
industry and global sugar producers.
As for soda being linked to poor
eating patterns, "you don't know
which is cause and which is effect,"
People who consume lots of
fresh-squeezed juice, vegetables and
fruits are fundamentally not the
same as those who subsist on colas
and bologna sandwiches, he contends.
"There is a difference: The first
group is rich," Drewnowski said. He
thinks government subsidies of
fruits and vegetables would be
better public policy than taxing a
cheap source of calories.
He also disputes the claim that
soda calories are not satisfying. He
did a study in which 32 men and
women were given either colas or
fat-free Raspberry Newtons before
lunch on four separate occasions.
"There was absolutely no
difference in satiety" as measured
by how much they ate or how hungry
they said they were, he said.
That research was paid for by
industry, a factor that can affect
study outcomes, said Kelly Brownell,
a psychologist and food policy
researcher at Yale University and a
vocal advocate for curbs on soda and
When you look at studies
according to who footed the bill,
"the literature parts like Moses
parting the ocean," he said,
referring to the biblical parting of
the Red Sea.
Does the evidence add up to a
conviction of soda?
One of the nation's leading
epidemiologists who has no firm
stake in the debate, the American
Cancer Society's Dr. Michael Thun,
thinks it does.
"Caloric imbalance causes
obesity, so in the sense that any
one part of the diet is contributing
excess calories, it's contributing
causally to the obesity," Thun said.
"It doesn't mean that something is
the only cause. It means that in the
absence of that factor there would
be less of that condition."
Does it merit a warning on soda
"I think it would be a good
candidate for a warning," Thun said.
"It's something that should be