Is juice good or bad for you? When I say juice I dont mean with all the preservatives.
Generally speaking, bad. When I think juice I'm not thinking store baught commercial juice, but homemade fresh natural juice. If that's the case, how can it be bad you might be thinking. In a word: unnatural. Or if you like, incomplete. In fact at times, natural juices can be more than bad, they can even be harmful, by adding to your already unready gut flora. What do I mean by unready? I mean a microbiome environment that is not as powerful as it should be due to the processed foods one eats these days.
So when can some freshly homemade juice be good for you then? When you're hungry and thirsty, and post some exercise. Why is that? Because at these times, the sugar, make that the concentrated sugar of the fresh juice, won't be lingering around in your system going off fermenting and causing / adding to an already not so great internal environment. When one is hungry, thirsty, and post workout; the body is in a much more receptive state than when one's tummy is already full with other food, or when one is just sitting down watching a movie etc.
I've tried veganism, raw, juicing etc...and found none could meet the power of a single egg yolk.
Some people don't tolerate the rise and fall of the hormone insulin like others can, and would suffer all the ill consequences of either a high blood sugar level, or a high and lingering insulin level. Both are not great, as your aim is to have a stable level of blood sugar, and not something that might add to its yo-yoing effect, such as that that can be created by consuming juice. Have an apple instead of apple juice whenever possible, otherwise, enjoy some juice at the most appropriate of times (as I've already mentioned above).