If you're going to conclude that diet soda consumption is linked to weight gain and increased abdominal circumference you'd damn well better control for diet as a whole given that diet beverage consumption may simply be a marker for people who eat more indulgent foods and think, erroneously, that choosing the diet pop with their mega combo will somehow protect their weights and waists, and because there is no known plausible mechanism for a direct link. This study didn't.
This new paper has made international news, and as you might imagine, that critical methodological shortcoming up above, is missing from much of the coverage and certainly all of the headlines including this Dr. Sanjay Gupta tweet which included a graphic and a teaser and was sent out to his nearly 2 million followers:
Honestly, that researchers would feel comfortable publishing a study with the end points of weights and waists, and not control for diet and caloric intake, is just mind boggling. Seeing the study published also makes me wish for more transparency in peer review. Would love to know who thought this was publishable as is.
(and for the conspiracists out there, I don't consult for, or own shares in, any artificial sweetener or soda company, and I think we should be striving for less sweet as a whole, including from artificial sweeteners, but I'm also for evidence based recommendations, peer review, and media coverage)