Calorie 09 : One energy calorie is equivalent to 4.2 joules. Thus, it takes 500,000 calories of energy to boil a pot of coffee. One food calorie equals 1,000 energy calories
United States Department of Agriculture USDA, Glossary of Terms, Washington, DC, USA 2014. http://www.usda.gov/energy/matrix/FindTerms, (Oil - Amer) {780}