Yes, they are. Studies have shown that people who drink soda everyday gain around 15 pounds a year just from drinking soda. Carbonated Beverages tend to be high in sugar as well which can corrode teeth.
It is not the carbonation that is necessarily "bad" for you. Overconsumption of anything is a poor choice for one's digestive system and overall health, but the magnitude of calories and artificial sweeteners in these drinks are things people need to be wary of.
