You guys are always talking about insulin spikes. Remember, there's a difference between eating a piece of fruit (or even a spoonful of sugar) on an empty stomach, or having it when you've got a bellyful of meat and fat to dilute the effects.
Excessive Fruit Intake Can Cause Diabetes?
While this is one individuals response to a high fruit diet, it does call to question what sort of vulnerabilities were in place in his body to make him react to fruit in such a way. And I think it is cautionary.
If you're worried about fruit consumption, maybe pick up a blood glucose monitor and check your levels after you eat a piece of fruit. If your blood sugar is spiking, it's probably best to limit your fruit intake. If not, it's probably still a good idea to cut back to maybe 3 pieces a day.
And like dragonmamma mentioned, eating the fruit with something more hearty, almond butter, cheese, meat, would likely offset any spikes you might experience.