Metabolisable energy (kcal ME)

Metabolisable energy is the energy actually available to the animal after faecal and urinary losses, expressed in kilocalories per kilogram of food or per serving, and it underpins ration calculation. For processed pet foods, manufacturers commonly apply modified Atwater factors, which FEDIAF bases on average digestibilities of roughly 90 percent for fat, 85 percent for carbohydrate and 80 percent for protein, assigning 3.5 kcal per gram of protein, 3.5 kcal per gram of digestible carbohydrate and 8.5 kcal per gram of fat (FEDIAF Nutritional Guidelines). A more accurate figure comes from in vivo digestibility trials. A nuance worth knowing: modified Atwater factors tend to underestimate energy in low-fibre diets and overestimate it in high-fibre ones, so two foods can be compared more fairly when this is borne in mind. Complete food labels must state energy content, which lets owners compare two products at equal weight and adjust portions to prevent excess weight gain over time, linking metabolisable energy directly to [overweight](/glossary/overweight) and [obesity](/glossary/obesity) prevention. The marker: metabolisable energy is the practical currency of feeding, the figure that turns a recipe into a portion, and reading it on the label is the simplest defence against gradual weight gain, a habit encouraged throughout the [Petipedia glossary](/glossary). It also helps interpret the calorie density of [wet food](/glossary/wet-food) versus dry.

Petipedia · Editorial team

General documentary information. For an individual animal, a veterinarian's advice takes precedence over any online content.