"What we saw was that the more diet sodas a person drinks, the more weight they were likely to gain," she says.
That finding was a big surprise, but it reflected what nutritionist Melainie Rogers saw in her work with obese patients in New York. "When we would switch them on to diet soda off regular soda, we weren't seeing weight loss necessarily, and that was confusing to us," Rogers says. But why would diet soda make some people gain weight? There are only theories at this point but it may be as simple as people consciously eating more because they think they can. Khristianne Corro says, "If I'm having one of those pig out days, then yeah, I figure maybe it'll balance it out a little bit." And Tomczak says, "I'm drinking the diet soda and you know let me have that hamburger and fries, instead of just the hamburger alone." Researchers say physiology may also play a role. "When I put anything to my stomach that's not water then my stomach responds by increasing the gastric acid secretion," Fowler says. "Does that increase my sense of hunger and does that drive me to eat more?" If diet soda really doesn't take the weight off, it wouldn't be the first time a diet product failed to perform as expected.
