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Transcript of FOOD and the FIRST LAW OF THERMODYNAMICS
FOOD 
and the
FIRST LAW OF THERMODYNAMICS 
500 Calories Per Serving 
What exactly is meant when it says under the nutrition facts that one serving contains 500 calories? 
It is referring to the enthalpy of combustion of your food. The amount of calories tells you how many kilocalories (1kcal/4184J) you are consuming and how many kilocal will be able to use. The amount of energy is found by measuring heat combustion of waste products excreted by an organism on a controlled diet.