By Shari Rudavsky, The Indianapolis Star
Diet soda, it turns out, may not be the panacea for weight loss that we all thought - and many of us hoped - it was.
In fact, a Purdue University
study has found that diet sodas may be linked to a number of health
problems from obesity to diabetes to heart disease, just like their more
Susie Swithers, a professor of psychological sciences and a behavioral neuroscientist, reviewed a number of recent studies
looking at whether drinking diet soft drinks over the long-term
increases the likelihood that a person will overeat, gain weight and
then develop other health problems.
One large study found that
people who drank artificially sweetened soda were more likely to
experience weight gain than those who drank non-diet soda. Others found
those who drank diet soda had twice the risk of developing metabolic
syndrome, often a precursor to cardiovascular disease, than those who
Surprisingly, some of the studies suggested diet soda may be just as bad for our health as non-diet.
diet sodas worse for you than regular sodas? I think that's the wrong
question," said Swithers, who is also a member of Purdue's Ingestive Behavior Research Center. "It's, 'What good are sodas for you in the first place?' "
studies included drinks containing aspartame, sucralose and saccharin.
About 30 percent of American adults regularly consume these sweeteners.
research indicating that diet soda might not be a health food has been
around a few decades, in the past 25 years, Americans' consumption of
these drinks have skyrocketed, among a proliferation of options and
concerns over obesity.
Such thinking has driven many schools and
hospitals to stop offering sugary sodas in their cafeterias and vending
machines in an effort to improve the health of their patrons.
research, such as that done by Swithers, suggests that tactic could
backfire and that there could be serious long-term health consequences
to regular consumption of diet sodas.
In scientific terms, Swithers' piece is a review study, one that looks at many different studies to reach a conclusion.
The American Beverage Association, the trade association for the non-alcoholic drinks industry, described it a different way.
is an opinion piece not a scientific study," the organization said in
an emailed statement. "Low-calorie sweeteners are some of the most
studied and reviewed ingredients in the food supply today. They are a
safe and an effective tool in weight loss and weight management,
according to decades of scientific research and regulatory agencies
around the globe."
Many organizations, including the American Diabetes Associationand the Academy of Nutrition and Dietetics,
support the use of low- and no-calorie sweeteners to help maintain a
healthy weight, the trade industry statement pointed out. In addition,
it cited a number of studies that showed that drinking diet beverages
will not lead to weight gain or increase a person's desire for sweet
Swithers, whose laboratory research is funded by the National Institutes of Health, disputes that. Her paper appears in Wednesday's issue of the journal "Trends in Endocrinology & Metabolism."
studies have shown that when people drink diet soda, they engage in
what's known as "cognitive distortion," deciding that since they saved
on liquid calories they can splurge elsewhere - the "diet coke and
However, something else may be going on. Studies in animals note a
link between consuming artificial sweeteners and overeating that leads
to weight gain, said Swithers, whose own research relies on animal
models. Somehow artificial sweeteners throw off the body's ability to
know how many calories it needs.
"We think there's a much more basic fundamental learning process that's getting interrupted," she said.
when someone consumes something sweet, the body expects calories and
sugar to follow. But when a person drinks diet soda the payoff never
"You get this kind of confusion and that can lead to
overeating, and at least in the animal model that can lead to an
increase in blood sugar spikes," Swithers said.
Of course, diet
sodas are not the only places that artificial sweeteners creep into our
diets. Some yogurts and baked goods incorporate the no-cal sweet stuff.
Still, there's enough data on diet soda here, she added, for people to act.
take-home message is for people to be much mindful of how much
sweetener, whether artificial or sugar, they're actually consuming," she
said. "We're talking about a health issue here. We're not talking
necessarily just about weight gain or weight loss. ... Science suggests
that people who drink soda regularly end up with worse outcomes."