A study on the macronutrient regulation of petfood was conducted to determine how adult domesticated cats select what to eat, when given a choice of petfoods with different ingredient amounts.

The study, "Geometric analysis of macronutrient selection in adult domestic cats, Felis catus," looked at whether adult domesticated cats, given a choice of three foods with variable amounts of protein, carbohydrate and fat, would deliberately select a food that is biologically appropriate for them.

The study found that when the cats were restricted to a high-carbohydrate food, they did not eat enough of it to get the targeted amount of protein. The cats who were more experienced in eating dry foods increased their protein intake and ate a smaller amount of carbohydrates than cats with little experience who were offered the same choices in the study.

According to study authors, when given a choice, cats learn to avoid eating an excessive amount of carbohydrates because they do not produce the enzymes required to digest high amounts of carbohydrates. Authors also said that results indicated that strong nutritional regulation of petfood is important for proper formulation of cats' diets to account for macronutritional differences between wet and dry commercial cat foods