Many dieting books advise against juice. Not because of the calories, but because it bypasses some parts of the digestive system (you don't chew juice or soup, for example).

I have heard that fructose -- as present in fruits and juice -- can suppress the body's sensation of fullness, causing people to eat more. Some people advance this theory as a reason to not eat or drink anything containing high-fructose corn syrup. I was able to find studies both supporting and refuting the theory, though, so I'm not sure if it is true. Both sites obviously have their own agendas:

http://www.naturalnews.com/022836.html

http://www.hfcsfacts.com/UofWResearchAJCN.html

Even still, drinking a glass of orange juice delivers fewer nutrients than eating an orange, and of course you don't get any of the fiber, either.

Pretty much every drink other than water is empty calories.

I'm not saying people shouldn't drink juice. Juice tastes great and is a gentle morning eye-opener. That's why I drink it.