As someone who has been paying a lot of attention to healthy foods in recent days, I have to disagree with this assertion. Soft drinks generally do contain less calories per ounce than an equal amount of fruit juice, but as you show, the difference is about 50-100 calories. This amount can easily be compensated for with about 20 minutes of moderate exercise.
Also, soft drinks provide no nutritional benefit, carbonated drinks can make acid reflux and fluid retention worse, and their added caffeine has been linked to bone loss (possibly by not allowing calcium absorption). Juices, although stripped of a majority of the fruit’s nutritional content, still contain vitamins and aren’t going to bloat you like the Goodyear Blimp. I’m not saying skip the fruit for a juice, but if I have a choice between Coke and orange juice, I’ll take the juice.
It is true that fruit juices contain nutrients that soft drinks don’t, but these nutrients come with problems. If you eat reasonably, you already get “enough” nutrients and do not need supplements. So by adding fruit juices to your diet, you may be getting “too many” nutrients. I have yet to see convincing data suggesting that the average person benefits from more than “enough.” In fact, studies pop up here and there saying that more than “enough” can harm you.
Trilia suggested you can exercise an extra “20 minutes” (a day?) to counteract the fruit juices. Suppose you normally exercise 30 minutes a day, every day. That mean the first 20 minutes has no net benefit; it just counteracts fruit juice. Why not quit drinking fruit juices, thereby making all 30 minutes of exercise a productive effort?
I guess I wasn’t clear on one point. The absolute best hydrating substance for almost every situation is plain water. My point in comparing fruit juices to soft drinks is to show that fruit juices make you fatter than a form of junk food.