Artificial Sweeteners May Damage Diet Efforts
Sugar Substitutes May Distort the Body's Natural Calorie Counter
June 30, 2004 -- Sugar substitutes may offer sweet treats for
calorie-conscious dieters, but a new study shows that they may also play tricks
on the body and sabotage weight-loss efforts.
Researchers say artificial sweeteners may interfere with the
body's natural ability to count calories based on a food's sweetness and make
people prone to overindulging in other sweet foods and beverages.
For example, drinking a diet soft drink rather than a sugary
one at lunch may reduce the calorie count of the meal, but it may trick the
body into thinking that other sweet items don't have as many calories
Researchers say the findings show that losing the ability to
judge a food's calorie content based on its sweetness may be contributing to
the dramatic rise in overweight and obesity rates in the U.S.
But don't ditch your diet drink yet.
"The message is not to give up your diet soda and go drink
a regular soda," says researcher Susan Swithers, PhD, associate professor
of psychological sciences at Purdue University. "But when you do drink
beverages you probably need to pay a little more attention to whether they have
calories or not and what the consequences of that fact will be on the rest of
Sweetness Provides Calorie-Counting Clues
Swithers says that in the past, a food's sweetness provided
valuable clues about its caloric content, and something sweet was usually a
good source of energy.
"Before things like artificial sweeteners, these
relationships would be very reliable," says Swithers. "Animals needed
to find good sources of calories and needed to know whether eating something
provided them with lots of calories."
"It's only been relatively recently that foods have been
introduced that violate those kind of relationships, such as something very
sweet that has no calories," Swithers tells WebMD.
According to researchers, the number of Americans who consume
sugar-free, artificially sweetened products has grown from less than 70 million
in 1987 to more than 160 million in 2000.
At the same time that more people are drinking and eating foods
sweetened with low-calorie sweeteners, such as aspartame and saccharin, they're
not getting any thinner. In contrast, more people are becoming overweight or
That prompted researchers to test whether not being able to use
sensory clues to predict the calorie content of foods might contribute to
overeating and weight gain.
Artificial Sweeteners May Trick the Brain
In the study, published in the July issue of the
International Journal of Obesity, two groups of rats were fed either a
mix of high-calorie, sugar-sweetened, and low-calorie, artificially sweetened
liquids; or sugar-sweetened liquids alone. This was fed to the rats in addition
their regular diet. After 10 days, they were offered a high-calorie,
The study showed that rats fed the mixed liquids ate more of
their regular chow after the sweet snack than those who had been fed
sugar-sweetened liquids alone.
Researchers say the results show that the experience of
drinking artificially sweetened, low-calorie liquids had damaged the rats'
natural ability to compensate for the calories in the snack.