There's afaik a rather big difference between freshly squeezed orange juice, and fruit juices that have been pasteurised. I'm not sure there's that big a difference between eating an orange and drinking the juice - other than the simple fact that the orange will contain "more stuff" that is "not sugar" than the juice - hence it'll be easier to increase sugar intake by drinking, say a litre of orange juice a day, and eating some food - rather than eating six(?) large oranges and being reasonably full.