Fruits aren't bad. Yes, fruits have sugar, but many fruits have a decent amount of fiber, as well. Fiber helps slow down sugar absorption. It's not that shouldn't have any sugar in their diet, ever. Natural sugars, eaten at the right time, in the right combination are better than processed garbage which will spike your blood sugars instantly. A good rule of thumb is whenever you're having anything that has fruit in it, it's a good idea to have protein right along with it. Even if it's just a few almonds or walnuts alongside that piece of fruit.

Nah, most fruit is not energy-dense enough to cause you that kind of trouble. There's not enough room in your stomach to become obese on fruit.

If you're eating a ton of fruit a day, keep doing it! It's probably the healthiest thing you can put in your mouth.