Sugar.
What’s unhealthy off the bike might be fine on the bike.
Sugar is perfectly fine when fueling a hard workout. Specifically talking about the frequently discussed 1:1 blend of fructose to glucose.
Fruits and veggies are just going to give you a bunch of fiber that you don’t need on the bike. Fruit is good, but != rocket fuel.
Now if you’re talking about pre or post ride fueling, that’s a different story…