I need your expertise. is a fruit smoothie, with nothing but fruit added, healthy?

Sure: If blood sugar problems - watch over all sugar intake.

Healthy smoothie.: I don't like your having just the fruit in there. I'd like to see a source of protein to help with overall absorption and balance. Perhaps protein powder to keep the calories down. Maybe blend it in skim milk. And I usually recommend adding some psyllium husk to get back some of the fiber benefit.