if you wait to eat fruit when it's ripe, the cell wall converts into sugars and the issue i'm exploring with carrots & mushrooms (and exists with virtually any vegetable) is much less pronounced.
and, it's easy to tell when a fruit is ripe - it's soft, because the cellulose has degraded.
it's for that reason that vegetables may often have higher nutrient contents in theory, but fruits are actually better for you - vegetables (especially "leafy greens") often just end up as useless fibre.
in my diet, bananas, strawberries, avocados, kiwis & red peppers are all fruit. tomatoes are also fruit. only the carrots are difficult to digest.