A kilocalorie is the amount of heat required to raise the temperature of 1 kilogram of water to one degree Celsius. In nutrition and exercise, the terms "calories" and "kcal" are used interchangeably and refer to the same amount of energy. Therefore, if a heart rate monitor reads that you have burned 250 kilocalories while working out, it would be the same as burning the 250 calories you consumed from drinking a 16-ounce bottle of regular soda. The number of calories in a food item represents the potential amount of energy from that food. It is important to note that the term "calorie" is often used to refer to the small unit of energy, while "kilocalorie" is used to refer to the large unit. However, in nutrition, the terms "calories" and "kcal" are used interchangeably and refer to the same amount of energy. To convert from calories to kilojoules, multiply calories by 4.18. Conversely, to convert from kilojoules to calories, divide kilojoules by 4.18.