[Kirby]

I think this nails it. If you're part of a conscious diet and watching calories, diet soda can be a good choice, because you're _explicitly_ controlling for the effect the study is about - the false sweet causing cravings and ultimately more calorie consumption. It might follow, though, that the diet soda makes the rest of the diet more difficult.

If you're just subbing in diet soda for regular and not paying particular attention to overall diet, though, this study argues that you'll overall lose, as the diet soda increases your cravings for sweet and, left unchecked, you'll gain weight. Seems plausible.

(I don't worry too much personally, since I'm part of the population to which artificial sweeteners are not palatable. I'd rather drink water, and I do quite often.)