Here’s a good read on the science (and politics) of soda and sugar. For researchers, a key point is:

“If you looked at the secondary endpoints in these studies, said Allison, then yes, each of the studies found one statistically significant result: but they were all for different things and so provided no evidence of consistency that might adduce causality. What was troubling—what the field of obesity research had to avoid—was spinning these secondary endpoints into major findings. You just can’t do this when they weren’t the endpoints you built your study to examine.”