Cats cannot eat egg whites because egg whites contain a large amount of avidin. If the cat eats it, it will affect the absorption of vitamin B and cause skin and hair problems. Moreover, egg whites also contain some bacteria that may cause cat diseases. Gastrointestinal discomfort. It is best to feed the cat egg yolk directly, which makes it easier for the cat to absorb nutrients and does not increase the burden on the gastrointestinal tract.