Fruit _juice_ is more problematic. Drinks release a large amount of sugar very quickly into your system, they also don't "fill you up" and it is hard to quantify exactly how much you have consumed, meaning that people consume more sugar than they intended to. Drinks are directly absorbed into your gut without requiring digestion, and you can also drink fruit much faster than you could ever chew the same amount of whole fruit.

So yes, do avoid fruit juice, soda, smoothies, alcoholic beverages, ice cream, etc; but avoiding whole fruit is probably premature optimisation.

I like the rough guideline to change from eating vegetables/juicing fruit to juicing vegetables/eating fruit.