When thinking about what to give your parrot to eat, think of what he ate in the wild. He ate fruit and nuts. You may think all fruits are fine to give him to eat and most fruits are safe. However, avocado is not good for parrots neither are the seeds of fruit. Most seeds contain cyanide and although it does not contain enough to kill a human, your parrot is a lot smaller than you are and therefore it will cause a lot of damage.
You should give your parrot organic pellets as a main food source. Fruits, nuts and vegetables, cooked or raw are given more as a supplementary food source. Birds in general need a lot of calcium, vitamin A, better known as beta-carotene, and leafy greens and mustard greens are a good source of the two. Broccoli is the best source of both.
By giving your parrot fresh fruit and vegetables, you will boost his immune system as fresh vegetables and fruit contain phyto-nutrients. This is known to help speed up healing and is thought to help prevent diseases. You can also give your parrot cooked rice and a very small amount of cooked (never raw) meat and fish for protein. This must not be given on a daily basis as in the wild parrots do not eat meat. Some parrots have been known to enjoy a bone with tit bits of meat on it.
Apples, berries (all berries that you can eat) banana, oranges, seedless grapes, melons, kiwi, mango, papaya (remove the skin off the mango and papaya), almonds and unsalted peanut or other nuts, are good for your parrot.
Spinach, beans, sweet potato, peppers (red, green and chili), peas, lettuce (not ice-berg or head) celery, collard, kale (excellent source of calcium), butternut, zucchini and cucumber are the right vegetables for your parrot.
Boiled eggs with the shell still on is a good source of protein and calcium.
DO NOT give your parrot coffee or chocolate: as it contains theobromine, this is an alkaloid that is poisonous for your parrot. Alcohol and salty foods must not be given to your parrot. Birds do not have sweat glands and therefore cannot get rid of the salt in their bodies.
Furthermore, if you provide pellets, fruit and vegetables you do not have to supplement your birds diet with other supplements. Too much vitamins can cause a lot of problems. Before supplementing his food, go see an avian specialist, they will be able to tell you if it is needed.