Kcal, or kilocalories, is a measurement that is interchangeable with the calories that you use to evaluate the nutritional content of your food. Technically, food calories each represent 1,000 of the unit of heat energy scientists refer to as a calorie. In scientific writing, the nutritional calorie, or kilocalorie, is capitalized to differentiate it from the smaller calorie unit. However, popular writing and reporting tends not to follow this convention, so in nutritional concerns, you can be confident that even lowercase calories are the equivalent of kilocalories. There are a variety of methods for estimating your daily caloric expenditure, including predictive equations, indirect calorimetry and metabolic equivalent estimations. However, dietitians often use a quick calculation of 25 kcal per kilogram of body weight per day for individuals who want to maintain their weight.
Step 1
Divide your body weight, in pounds, by 2.2 to convert it to kilograms. For example, a 160-lb. person weighs 72.7 kg because 160 divided by 2.2 equals 72.7.
Step 2
Multiply your weight, in kilograms, by 25 kcal to an estimated daily caloric expenditure based on your weight. For example, a 72.7-kg person burns about 1,800 kcal per day because 72.7 times 25 equals 1,818.
Step 3
Divide your estimated caloric expenditure by 24 to calculate your average caloric expenditure per hour.
Tips and Warnings
- For more exact calculations of daily and hourly caloric expenditure, you will need to take an indirect calorimetry test to establish your resting metabolism and then calculate the time you spend on exercise and other daily activities as well as the relative intensity of those activities. For overweight individuals who wish to lose weight, dietitians recommend 20 kcal per kilogram of body weight per day. For underweight individuals who wish to gain weight, they recommend 30 kcal per kilogram per day.
References
- "Krause's Food and Nutrition Therapy: 12th Edition"; L. Kathleen Mahan, et al.; Escott-Stump; 2008
- Surgisphere Corporation; "Clinical Review for the USMLE Step 3"; 2008
- The Pocket Doctor; Nutrition Equations; 2001
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