"I think there are multiple things that are contributing to this," Swithers said. "Psychology is a factor, but physiology can also be altered."
Based on her research, she said, water is the best bet for people who are trying to lose weight or improve other measures of health.
"The downside to drinking the diet sodas is that they may undermine these unconscious processes that could help us regulate our weight and other things like blood sugar," she said.
For more about the dietary impacts of drinks, head to the U.S. Centers for Disease Control and Prevention.
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