An adult cat has nutritional needs that must be met to keep them healthy. Their food must above all be:
Rich in quality animal proteins. To maintain lean body mass (muscle, tone, immunity, coat, skin, healthy digestion...), the food consumed must provide between 5.2 and 6 grams per kg of optimal body weight per day. It can be more, but not less than 5 grams per kg of adult cat weight. Beyond quantity, protein quality also matters. Quality proteins have two characteristics: they are highly digestible and provide all the amino acids a cat needs. Since a cat's natural diet consists of small prey, we try to replicate their amino acid profile in ready-made food. For dry food, several protein sources must be combined, partly for technical reasons. For wet food, a mouse-like profile can be mimicked using noble offal proteins (muscle proteins such as heart, an excellent protein source), with liver or lung in smaller proportions (without cartilaginous parts). Proteins from carcasses and cartilage are less interesting in terms of amino acid content (high in collagen, characterised by its typical hydroxyproline content) and mineral content.
Balanced in minerals. Their food must contain minerals, but not too many, as these are excreted in urine. Cats have concentrated urine and are sensitive to urinary crystals. High levels of phosphorus are toxic to the kidneys!
Low in carbohydrates. When there is an excess of NFE (starch and sugars) relative to the cat's energy needs, glucose is stored as glycogen or converted into fat by insulin. A diet too rich in carbohydrates, beyond being poorly digested by many cats, could have consequences for their health: overweight, obesity, and diabetes.
Balanced in fibre. Fibres are carbohydrates that cats cannot digest. They support healthy digestion and good stool consistency.
Balanced in fats. Fats or lipids are also essential for all cats: a highly efficient calorie source, they serve as fuel. Lipids are a major component of cell membranes, nerves, and the brain. They also provide thermal and mechanical protection for vital organs, contribute to the skin's barrier function, and keep the coat lubricated and shiny. Although essential, fats are calorie-dense and their content should remain reasonable to allow a satisfying quantity of food without excessive caloric intake.
Rich in essential fatty acids. Fats are made up of small units called fatty acids. There are several families of fatty acids: some that cats can produce themselves, and two that they cannot but which have vital functions. Cats must therefore obtain these from their diet, in particular omega-6 and omega-3.