Completely agree with the above posts. Soft drinks are cheap, easy, and they taste good. It's hard to convince people they should drink water instead, when there's a convenient can of sugar water next to them. Of course, soft drink companies would also like you to believe that they hydrate the body, by using the argument that all liquids hydrate. But due to the large amounts of sugar, soft drinks can actually dehydrate you.
Also, unless it’s sugar-free, most soft drinks contain high fructose corn syrup. High fructose corn syrup has been associated with an increased risk of metabolic syndrome, a condition associated with an elevated risk of both diabetes and heart disease. HFCS is also believed to be a major contributor to the obesity epidemic among children and teens. Although similar in calorie content to table sugar, the danger of high fructose corn syrup arises from the way it’s is metabolized by the liver. By being broken down more rapidly than other sugars, it can lead to alterations in triglyceride and lipid metabolism, thereby increasing the risk of heart disease and fatty liver, not to mention diabetes. Although the soft drink industry has tried to underplay the risks, evidence supporting the dangers of high fructose corn syrup is mounting.
The amount of caffeine, while less than say coffee or energy drinks, still contributes to caffeine dependence in children. It can lead to headaches, crankiness, stomachaches, and fatigue when not consumed. Also, soft drink consumption has been linked to the development of cellulite in the body....the dreaded "cottage-cheese thighs".