Most informed people will feed some combination of vegetables, fruits, seeds, pellets, fresh sprouts, homemade mash with veggies and grains, a few nuts, etc. Not everyone feels ALL those things. Some people do, some people feed some sort of a combination of a couple or few items above.
I could see where it can get confusing when you hear about it varying. It's confusing because birds can have such a variety, unlike maybe some exotic pets (or even cats) who need a pretty narrowed down specific diet.
As far as what vegetables or fruit, you just have to experiment what he likes. Veggies are more nutritious than fruit and have a longer life against spoilage in the bowl. No avocado or onion. Having these fresh foods around gives the humans plenty of nutritious foods to eat too! Especially if the bird doesn't like it. Some days they will love a certain veggie, the next day or week, they'll not be in the mood for it, so that means lots of waste. We hate that, but there's no way around it.
Some people supplement the dry portion of the diet with pellets. Some people prefer only seed and no pellets. Some people use both seed and pellets. As far as pellets go, I'd say the two nutritionally superior brands are two organic types - Harrison's, and TOP's.
Many people, especially people who love to cook or create in the kitchen, like to create their own mash. Made of any variety of finely chopped veggies, different cooked grains such as quinoa, brown rice, buckwheat, lentils, wheat or wheat berries, beans, etc. You can even mix eggshells, and millet in. Be creative. People who make this type of mash usually put into ice cube trays because it's a perfectly convenient shape and size to freeze and store in nice individual portions. Just pop one out and thaw when ready.
Also common, many people give their parrot a small portion of what the humans are eating for dinner. Though MOST foods are safe in small quantities, you really might want to go super small when giving food not made for birds, depending on what you're having, unless you eat really healthy. Your dinner might have lots of salt, sugar, fat, dairy, etc. A little should be fine though.
I think I remembered just about everything... If not, more members will be around to chime in with more ideas
Also you can look under the search feature to find older threads about diet which might give you new ideas, and a better understanding.
I hope that helps get you started.
Weren't you saying you don't have a bird yet, but are interested in Pionus? Pionus are said to get overweight fairly easily, so watch the fat content in human food you give, and not too many nuts on a regular basis. Also Pi's are sensitive to too much protein. Over time it can lead to Gout and kidney issues. Discuss these concerns in more depth with an avian vet. Good luck!
