Cat foods labeled as 'complete and balanced' must meet standards established by the Association of American Feed Control Officials (AAFCO) either by meeting a nutrient
profile or by passing a feeding trial. In 1995 the AAFCO's Feline Nutrition Expert Subcommittee revised their Cat Food Nutrient Profiles.
There are now two separate nutrient profiles for cats - one for growth (kittens) and one for adult maintenance. Maximum levels of intake of some nutrients have been established for the first time because of concern that overnutrition, rather than undernutrition, is a bigger problem with many pet foods today. The standards include recommendations on protein, fat, fat soluble vitamins, water soluble vitamins, and mineral content of foods.
The levels of nutrients in the table below are expressed on a 'dry matter' (DM) basis. On most pet food labels, the levels listed in the guaranteed analysis are expressed on an 'as fed' basis. To convert 'as fed' to 'dry matter' a simple conversion is necessary. If a dry food has 10% moisture we know that it has 90% dry matter. So we look at the label and check the protein level. That reads 20%. Next, we divide the 20 percent protein by the 90% dry matter and we get 22%, which is the amount of protein on a dry matter basis. Does this make sense so far? Good. Now let us compare this to canned food that has 80% moisture. We know that with 80% moisture we have 20% dry matter. The label shows 5% protein. So we take the 5% and divide it by 20% and we get 25% protein on a dry matter basis. So the canned food has more protein per pound on a dry matter basis after all the water is taken out. We can do the same for fat, fiber, etc.
AAFCO Cat Food Nutrient Profiles Published in 2008a