I think that most pet ekkie owners tend to feed a heavy veggie diet rather than fruit is because our birds are pets. In the wild they are breeding year round, raising young year round, defending their nests year round, looking for food year round, etc. All of this activity takes a tremendous amount of energy, which translates in a need for a calorie dense diet (heavy fuit (sugar) diet). In our homes, as pets, our ekkies just dont need all those calories..which translates into increased energy. When pet ekkies have a high sugar (high energy diet), they display even more hormonal behaviors (which we are always trying to keep to a minimum). Pumping a ekkie full of fruit (sugar) can be likened to giving a human toddler a ton of sugar and then wondering why that toddler is so hyper, crabby, difficult, etc.
I feed a veggie, grain, legume chop. So far it seems to be working pretty well but i do give fruit as a treat and i also give nuts and seeds as training treats and foraging treats.