Really, it’s the idea that you’ve got free rein to eat tons of fruit because it’s “healthy” that’s the problem. It’s natural, but it’s not that healthy. Any diet suggesting you eat a bunch of fruit is outdated
Avoid juice unless it’s juice you’re making yourself. Store bought juice is bad for you as in the processes they use to make it, fiber is taken away, so then the sugar just hits you like a ton of bricks.