An erg is a unit of energy equal to one 10 millionth of a joule. On the surface of the Earth, it takes about 0.98 ergs to lift a 1 milligram object by 1 centimeter.
A nutritional Calorie, or kilocalorie, is commonly used in food labeling. It is equal to 4.184 kilojoules. The average American consumes about 2,700 kilocalories per day.