Animal fats are often claimed to be unhealthy owing to their association with high cholesterol levels in the blood. Animal fat contains some cholesterol and saturated fat. Elevated blood cholesterol levels have been linked to heart disease, there is not necessarily a relationship between cholesterol intake and blood cholesterol level.
In pet nutrition it is the source of animal fat that has concerned food manufacturers. AAFCO states that animal fat is "obtained from the tissues of mammals and/or poultry in the commercial processes of rendering or extracting. It consists predominantly of glyceride esters of fatty acids and contains no additions of free fatty acids. If an antioxidant is used, the common name or names must be indicated, followed by the words "used as a preservative". In actuality the animal source is not specified or required to give the origin of slaughtered animals. The rendered animals can be obtained from any source. There is no control over quality or contamination and any animal can be used including dead, diseased, disabled, or dying prior to slaughter.