Cat food is food specifically formulated and designed for consumption by cats. During the 19th and early 20th centuries, cats in London were often fed horse meat sold by traders known as Cats' Meat Men or Women, who traveled designated routes serving households. The idea of specialized cat food came later than dog food, as cats were believed to be self-sufficient hunters. French writers in the 1800s criticized this notion, arguing that well-fed cats were more effective hunters. By the late 19th century, commercial cat food emerged, with companies like Spratt's producing ready-made products to replace boiled horse meat. Cats, as obligate carnivores, require animal protein for essential nutrients like taurine and arginine, which they cannot synthesize from plant-based sources.

Modern cat food is available in various forms, including dry kibble, wet canned food, raw diets, and specialized formulations for different health conditions. Regulations, such as those set by the Association of American Feed Control Officials (AAFCO), ensure that commercially available foods meet specific nutritional standards. Specialized diets cater to cats with conditions like chronic kidney disease, obesity, and gastrointestinal disorders, adjusting protein, fat, and fiber levels accordingly. Weight control diets often include fiber to promote satiety, while high-energy diets are formulated for kittens, pregnant cats, and recovering felines.

Alternative diets, such as grain-free, vegetarian, and raw food, have gained popularity, though they remain controversial. Grain-free diets replace traditional carbohydrates with ingredients like potatoes and peas but do not necessarily have lower carbohydrate content. Vegan and vegetarian diets have limited studies demonstrating their safety. Raw feeding mimics a natural prey diet but carries risks of bacterial contamination and nutritional imbalances. The pet food industry also has environmental implications, as high meat consumption increases pressure on livestock farming and fish stocks.

Nutritionally, cats require proteins, essential fatty acids, vitamins, and minerals to maintain their health. Deficiencies in nutrients like taurine, vitamin A, or arginine can lead to severe health problems. The inclusion of probiotics, fiber, and antioxidants supports digestive health, while certain vitamins like E and C help counteract oxidative stress. The pet food industry continues to evolve, balancing nutrition, sustainability, and consumer preferences while addressing emerging health concerns related to commercial diets.

During the 19th century and early 20th centuries, meat for cats and dogs in London, frequently horse meat, was sold from barrows (hand–carts) by traders known as Cats' Meat Men or Women. Henry Mayhew estimated in London Labour and the London Poor (1851) that the total number of cats in London might be 300,000. Each cats' meat seller had a particular route and served a few hundred households, their approach marked by mewing cats.

The idea of preparing specialized food for cats came later than dog food and dog biscuits. This was likely due to the idea that cats could readily fend for themselves. In 1837, a French writer Mauny de Mornay critiqued this idea:

It is... thought wrongly that the cat, ill-fed, hunts better and takes more mice; this too is a grave error. The cat who is not given food is feeble and sickly; as soon as he has bitten into a mouse, he lies down to rest and sleep; while well fed, he is wide awake and satisfies his natural taste in chasing all that belongs to the rat family.

In 1844, another French writer, Nicolas Jean-Baptiste Boyard, expanded on this idea: