A cat's diet is a major concern for many pet owners, as the quality of food directly impacts their health. Providing nutritious and healthy food for your cat is something every owner should do, and it's essential to understand what foods cats can and cannot eat. 
I. Dietary Considerations for Cats
1. Canned food
These foods contain meat, fish, salt, gelling agents, vitamins, artificial colorings, water, and grains. Most are made from fish, chicken, beef, rabbit, or animal offal. They contain 25%–30% protein and can be a primary source of nutrition for cats. Canned food can be used to feed cats because it is sterilized and easy to store. However, due to its high water content, the canning process and storage can lower the vitamin content.
2. Dried foods
These biscuits contain cereals, fish, meat, yeast, vitamins, fat, and coloring. They are cheaper than canned or semi-moist foods and are easier to store and carry. However, they have the following disadvantages: they are low in fat and protein; and some people suspect they may cause cystitis in cats. If you feed your cat dry food, be sure to make sure it drinks water frequently.
3. Soft and moist foods
These pellets contain meat, soy, fat, vitamins, preservatives, artificial colorings, and often thickeners and sugar. They contain over 33% water. Their nutritional value is not very high. Soft, moist food is used as cat food because it contains just over 25% protein and is low in fat. This type of food is packaged in foil bags and can be stored, but not for as long as the other two types.
4. Meat
To prevent cats from contracting toxoplasmosis, all meat should be thoroughly cooked.
Because of the structure of their teeth, cats cannot chew their food. Therefore, you should chop or finely cut cat food into minced meat, or feed them large pieces of meat so they can easily tear it apart themselves. If you are using chicken as cat food, be sure to remove all the bones, as cats can easily get chicken bones stuck in their throats.
5. Grass
If your cat insists on eating grass or weeds, don't panic. Grass is beneficial for cats; it contains certain vitamins and can act as an effective emetic, helping them expel unwanted substances like hairballs. However, if your cat frequently eats grass, make sure the fertilizer used is non-toxic. 
II. Things cats should not eat
1. Cats fed liver and carrots are prone to rickets and may also be poisoned.
Studies have shown that the ideal calcium-to-phosphorus ratio in cat food is approximately 1:1. However, liver is low in calcium and high in phosphorus, with a ratio of 1:36 in fresh liver. If cats consume liver long-term, it can lead to calcium deficiency. External symptoms of calcium deficiency include: 1. Weakened stomach function, loss of appetite, and gradual weight loss. 2. Decreased activity, fear of heights, and reluctance to jump from heights. Severely calcium-deficient kittens may develop sunken shoulders and a narrowed pelvis, leading to constipation. In cold weather, kittens are also prone to hind limb weakness, which can lead to paralysis in severe cases. This is what we commonly call rickets.
Liver itself contains a large amount of vitamin A, and carrots contain beta-carotene. One molecule of beta-carotene can be broken down into two molecules of vitamin A in a cat's body. If a cat is fed liver and carrots for a long time, its vitamin A levels will be severely excessive, and the cat will be prone to vitamin A poisoning.
If your cat already enjoys eating liver, you can mix the new cat food with liver and feed it to your cat for about 10 days. After that, increase the amount of new food and decrease the amount of liver each day until your cat is fully adapted to the new food.
2. Raw fish and raw meat should not be eaten.
Feeding cats uncooked fish can cause vitamin B1 deficiency because raw fish produces an enzyme that destroys vitamin B1. A lack of vitamin B1 in cats can lead to seizures, heart disease, and intermittent shock.
Furthermore, feeding cats raw fish can introduce unnecessary parasite problems, causing difficulties for both you and your cat. The Agricultural University Animal Hospital has treated many cats with liver disease caused by parasites contracted from eating raw fish, leading to jaundice and hepatitis. Liver disease can also cause ascites and kidney disease, which are practically incurable illnesses for cats.
Cats are quite picky eaters and can be said to love meat, so meat must be a part of their diet. This is very important for their health, so don't assume that cats are vegetarians.
