I really don't understand what you're not getting about this. No one's confused about sugar in apples versus juice. No one is confused about serving sizes. Move past that.

The question was are there exact standards. Is it based upon sugar content? Is it just all liquids? What's your criteria? You said what's healthy but that is so incredibly subjective I don't know why you'd even bother writing it. You could find a dietitian to say you shouldn't eat basically everything. Absolutely grapes. I'm not saying that. It seems like you're not saying that. Which is why I'm confused because earlier your criteria, high sugar low fiber, would seem to exclude them.