Time has an interesting article summarizing a study done at Perdue University on animals and how their bodies responded to artificial sweeteners. More specifically, how their metabolism responded. The results are a bit surprising:
When an animal eats a saccharin-flavored food with no calories, however — disrupting the sweetness and calorie link — the animal tends to eat more and gain more weight, the new study shows. The study was even able to document at the physiological level that animals given artificial sweeteners responded differently to their food than those eating high-calorie sweetened foods. The sugar-fed rats, for example, showed the expected uptick in core body temperature at mealtime, corresponding to their anticipation of a bolus of calories that they would need to start burning off — a sort of metabolic revving of the energy engines. The saccharin-fed animals, on the other hand, showed no such rise in temperature. "The animals that had the artificial sweetener appear to have a different anticipatory response," says Susan Swithers, a professor of psychological sciences at Purdue University and a co-author of the study. "They don't anticipate as many calories arriving." The net result is a more sluggish metabolism that stores, rather than burns, incoming excess calories.
So does that mean you should ditch the artificial sweeteners and welcome sugar back into your life? Not exactly. Excess sugar in the diet can lead to diabetes and heart disease, even independent of its effect on weight. But it's worth remembering that when it comes to counting calories, it's not just the ones you eat that you have to worry about. The calories you give up matter too, and they may very well reappear in that extra helping of pasta or dessert that your body demands. Your body may actually be keeping better count than you are.