Assuming your macro-nutrients are relatively balanced, your caloric maintenance level will determine the range of calories you’ll need to ingest each day to facilitate your body composition objectives. To gain weight, you should eat above it, and to lose weight, you should eat below it. Groundbreaking stuff so far, right? Yeah, you’re welcome.
To calculate caloric maintenance, first you’ll need to calculate your basal metabolic rate. This reflects the number of calories you’ll need to take in to maintain weight if you spend a period of twenty-four hours being completely sedentary. Get ready, we’re about to do math.
Male: basal metabolic rate = 66 + (6.23 x weight in pounds) + (12.7 x height in inches) – (6.8 x age in year)
Female: basal metabolic rate = 655 + (4.35 x weight in pounds) + (4.7 x height in inches) – (4.7 x age in years)
This calculation method is called the Harris Benedict Formula. Multiply your basal metabolic rate by the appropriate factor below:
- Sedentary: BMR x 1.2
- Lightly active: BMR x 1.375
- Moderately active: BMR x 1.55
- Very active: BMR x 1.725
- Extra active: BMR x 1.9
The figure you arrive at is the calculation for the total number of calories needed by the body to maintain current weight. Of course, the figure isn’t exact, but it will serve as a guideline for you to base your nutritional intake on.
I suggest that you be conservative in adjusting your caloric intake relative to your caloric maintenance figure. For example, let’s assume you want to lose weight and you calculate your maintenance level at 2,600 calories per day. Don’t make the mistake of dropping your daily calorie intake radically, let’s say to 1,200, hypothetically. That’s a bad idea for numerous reasons, foremost of which are: (1) your body will adjust to the much lower number and do its best to slow your metabolism, and (2) you’ll feel like crap all day and have no energy. What you should do instead is drop from 2,600 calories to about 2,450. If it’s ineffective after a week or two, it’s easy to drop another 150 calories down to 2,200. Incremental progression allows you to maintain higher levels of energy and lends itself to easy adjustment. As always, keep detailed records of what you’ve eaten so you know what’s effective and/or ineffective.
National Institutes of Health Heart, Blood and Lung Institute. “Balance Food and Activity.” http://www.nhlbi.nih.gov/health/public/heart/obesity/wecan/healthy-weight-basics/balance.htm
Harris, Arthur & Benedict, Francis. “A Biometric Study of Human Basal Metabolism.” Nutrition Laboratory and Station for Experimental Evolution, Carnegie Institute of Washington. 1918.
Roza, AM. “The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass.” The American Journal of Clinical Nutrition. 1984.