What impact would improper feeding have on a cat’s health?

There are many things that can go wrong if you feed a cat improperly. It should go without saying that the risk of constipation and diarrhea is higher with an improper diet. Skin and hair problems are common. The kidneys and liver may also have to work overtime, so problems could develop with them also. Your cat is a carnivore. It needs a meat-based diet. It's best to provide protein from meat-based sources as opposed to plant-based sources.