When it gets the change, the parrot will namely select the most tasty seeds. It can do this when the bowl contains more feed than the bird needs. If the right amount of food is given, the bird will finish its bowl.
An example of a balanced diet for parrots is a vegetarian mix of fruit, vegetables, nuts, and beans (like apple, carrot, walnut, and soy beans). The downside of such a fresh diet is that it spoils faster and takes longer to prepare.
Another way to make sure the bird gets all nutrients it needs is to offer feed in a set composition, a pellet. The preferred diet consists of 80% pellet, with some pieces of vegetable and fruit on the side. Peanuts and sunflower seeds can then be used as a reward.