Is diet soda making you fat?

Seven's On Call with Dr. Jay Adlersberg
February 11, 2008 7:20:27 PM PST
There is some new, not-so-sweet news about diet soda Monday.A study finds it could actually trick your body into putting on weight.

Seven's On Call with Dr. Jay Adlersberg.

A big chink in the armor of weight control today. Scientists say the foods we think are helping us keep our weight down might actually be helping us putting our weight on.

This is a study that is sure to generate a lot of controversy amongst weight loss experts. It came from scientists at Purdue University, who studied rats on a diet that included artificial sweeteners.

The study suggests that the sweeteners could be sabotaging our attempts at weight control.

Foods with zero and low calories are plentiful. Among the most popular, diet yogurts and diet sodas.

"I try to keep away from all the sugar in regular sodas," one diet soda drinker said.

"I don't want the calories of a regular soda," said another.

But a new study suggests foods with artificial sweeteners could actually be tricking the brain into eating more.

The study found that rats given food with artificial sweeteners and zero calories actually ate more calories and gained more weight than rats who got sugar and calories.

The sweetener apparently fooled the brain.

"It seemed that it revved up their metabolism in a way normally such that they then blunted it when they started eating the diet food," Dr. Mari Savard said. "There's something about diet foods that changes your metabolism, changes your brain chemistry."

Fifty-nine percent of Americans drink diet soda. While the rat study suggests what might be happening in humans, previous studies seem to support the link between the consumption of artificial sweeteners and added calorie intake.

"There are two large studies recently, over 18,000 people followed from five to nine years where they found healthy adult people consuming as little as one diet drink a day could increase their risk of metabolic syndome, pre-heart disease and weight gain by 30 to 40 percent or more."

The Calorie Control Council, an industry group of foods with artificial sweeteners, disputes the study and says the causes of obesity are many.

But it's already making some diet soda drinkers stop and think.

"I"ll stop drinking it, because if it's going to add wait to me, it defeats the purpose," one diet soda drinker told us.

Now, we are very careful when we report rat studies because they might not apply to humans. And what most scientists are sure to agree on is that the effect of artificial sweeteners on weight is something that bears studying more closely.