CALORIES - 1. This refers to the energy that is supplied by energy nutrients (foods). Activity will "burn" calories resulting in the need for additional calories from food. 2. A small calorie is the amount of heat required to raise the temperature of 1 gram of water 1 degree Celsius. A large calorie (kilocalorie) is the amount of heat required to raise the temperature of 1 kilogram of water 1 degree Celsius.