*1 Calorie =1 kilocalorie =1,000 calories. The term Calorie that is used on food nutrition labels is really a “food calorie” sometimes called a “large calorie.” It is equivalent to 1,000 calories (or 1 kilocalorie) as calories are defined scientifically (the amount of energy needed to warm 1 gram of water 1°C). In Nutrient Requirements of Dogs and Cats, energy needs are expressed in terms of kilocalories, which are equivalent to Calories in this document.