Type “diet soda” and “weight” into your favorite search engine and you may be surprised by what you find.

“Drink More Diet Soda, Gain More Weight?” asks one headline. “Diet Soda: Doorway to Weight Gain” shouts another.

In a recent search of a popular Web browser, 49 of the first 50 hits were for stories warning diet soda drinkers that the beverages might make them pack on the pounds.

The sole exception was the Wikipedia entry for "diet soda," which also cited the weight gain concerns.

If you believe what you read on the Internet, it’s clear that drinking diet sodas causes weight gain, right?

Maybe, but probably not, obesity researcher Barry Popkin, PhD, tells WebMD. What is clear is that the science is far from conclusive.