Fruit juice today, is basically sugar water with some fruit flavor. Even if there is no added sugar.

Fruit itself has much, much, much more sugar than it did in pre-agricultural times. Humankind had taken the sweetest fruit, planted seeds from it, chose the sweetest of those to replant, and over the period of time have developed fruit that has many times the sugar content of the historic wild variety.

In a way, fruit today is genetically modified. Most of it has way too many carbs for me to eat without getting out of ketosis.

Bob