Registered dietitians are talking about high fructose corn syrup.
"No single food or ingredient is the cause of obesity or overweight children. Eating too many calories and getting too little exercise causes it."
"There’s no one reason why we’ve seen the escalating rates of childhood obesity -- it all comes down to calorie balance. Kids are eating too many calories and not burning off those calories by being active. It’s a reality that kids are going to have some sugar in their diets, whether that’s table sugar, honey, pancake syrup or high-fructose corn syrup. Just be sure the majority of the added sugars they consume are from a nutrient-rich food or beverage, and practice moderation with concentrated sweets like candy and desserts."
"It is tempting to blame HFCS for the increase in the prevalence of obesity in the US since the increased use of HFCS temporally coincides with the increase in the prevalence of obesity. It is important to emphasize that the simultaneous occurrence of two events does not necessarily mean that one caused the other. The prevalence of obesity and diabetes is increasing even more rapidly in parts of the world where HFCS is not used in any significant amounts."