In "Fed Up," a documentary film that probes the supposed causes of America's obesity epidemic, you hear the alarming statistic that "One soda a day increases a child's chance of obesity by 60%."

Authors of the study this statistic comes from note their findings "cannot prove causality" — but that's not what sugar-shaming movie producers would have you think.

Drinking too much calorie-loaded soda is likely unhealthy, but it's not the sole factor driving a rise in childhood obesity.

The CDC advises parents to do what they can to protect against obesity by encouraging healthy lifestyle habits that include healthy eating and exercise, both of which will likely do more for a child's waistline than trying to completely cut sugar.