Calories (Kilogram,thermoc.)
The kilogram calorie (also known as the large calorie, food calorie, or kilocalorie) is the energy to raise the temperature of one kilogram of water by one degree Celsius at a pressure of one atmosphere. This unit is widely used in nutrition to quantify the energy content of foods.
Btu
The British Thermal Unit (Btu) is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. It is primarily used in the United States to describe the energy content of fuels and the power of heating and cooling systems.