The Research Part 1: The Rat Studies continued...
“Frankly, we were stunned,” Swithers tells WebMD. “It really was a small study.”
In the first study, two groups of rats were fed sweet, flavored, cola-like liquids. For one group, the liquid was always sweetened with sugar so there was a consistent relationship between the sweet taste and calories. In the second group, the sugar-sweetened liquids were alternated with liquids sweetened with the artificial sweetener saccharin, so that the relationship between the sweet taste and calories was inconsistent.
After 10 days, the rats were given a sweet, high-calorie chocolate pudding. Those exposed to the caloric and non-caloric sweet beverages ate more of the pudding.
In another study, rats were fed high-calorie chocolate pudding or chocolate milk with their regular food. At the end of the month, the chocolate milk group had gained significantly more weight.
The first experiment suggested that by breaking the connection between sweet taste and calories, artificial sweeteners interfere with the body’s natural ability to judge calorie content, Swithers says. The second, that the body is less able to recognize energy delivered in liquid form.
In a later set of studies the researchers fed rats yogurt sweetened with sugar or saccharine in addition to their regular chow and found that the rats that ate the no-calorie sweetener took in more calories overall and gained more weight.