I don't get it, both groups of teens continued to gain weight and they called it a win, nothing improved, the kids were still on the road to obesity and sickness. Depending on who you talk to, because of the chemicals in diet soda the kids that are drinking diet soda have accelerated their journey to sickness. Maybe they think using diet soda to help kids get off regular soda is like using methadone to help get someone off heroine. I don't know, but I'm not buying it. If I were a conspiracy theorist, I'd say a soda company funded this study.
If you swap out consuming a chemical laden sugary substance for a chemically laden non-sugary substance then(in my small mind) it is the equivalent of swapping cow poop for horse poop. It's still poop! I get how hard it is to stop drinking soda entirely, I've done it and so have lots of other folks. We didn't slow weight gain, we lost weight and gained health! So, c'mon kids drop the soda ENTIRELY.