I've read you have to be careful with fruit juices because of the sugar content. You should be sure and dilute them at least 50/50 if you do try it. And just sip a little to see how you tolerate it.
My plan doesn't allow any fruit juices because of the sugar content and high calorie count. Crystal Light is delicious and zero calories. I'd suggest that over fruit juice.
Can I ask you how long did you have to do clear liquids before your surgery and I read that someone said that while she was on a diet before the surgery if she gained even one pound they would postpone did they tell you the same thing?