On July 8, 2004, the Health News of the Associated Press reported on the results of a study done at Purdue University where rats fed artificial sweeteners ate three times the calories of rats given sugar. The study published in the July 2004 issue of International Journal of Obesity suggests that sugar-free foods may play a role in the current obesity epidemic.
Researchers in this study fed two groups of rats sweet-flavored liquids for 10 days. One group got only sugar-sweetened liquids, while the other was fed liquids sweetened by both sugar and saccharin. After the 10 days, both groups of rats were given a sugary, chocolate-flavored snack and regular rat chow. The results were that both groups of rats ate about the same amount of the chocolate snack. But the rats fed both sugar and saccharin ate three times the calories of the rat chow than the rats fed only the sugar-sweetened drink.
To explain these results the scientists suggest that artificial sweeteners could be interfering with people's natural ability to regulate how much they eat therefore interfering with the ability to distinguish between high and low calorie sweets. They suggest that this could help explain why Americans have grown fatter over the past two decades even as the nation's consumption of artificially sweetened sodas and snack foods has soared.
Not everyone agrees with the conclusions of this study. Some scientists dismiss the conclusions, saying that studies on people don't indicate that. Adam Drewnowski, director of nutritional sciences at the University of Washington in Seattle, said, "They're extrapolating and saying that humans may not be adjusting to the artificial sweeteners because they're expecting calories and the calories are not coming in. I just think this is nonsense."
However, Susan Swithers, an associate professor of psychological sciences at Purdue and co-author of the study, said the study findings suggest the rats given the saccharin-sweetened drink ate more rat chow because they experienced an inconsistent relationship between sweet taste and calories. She stated "Consuming artificially sweetened products may interfere with one of the automatic processes our bodies use to regulate calorie intake."