Caloric needs are based on your metabolic rate, or the rate at which your body uses energy in the form of calories. Basal metabolic rate, or BMR, is a good foundation for determining caloric intake, but it does not account for exercise or activity. Coupling BMR with the Harris Benedict equation, a formula that uses your BMR, then applies an activity factor to determine your total daily caloric expenditure, accounts for activity and exercise for a more accurate quantification of your daily caloric needs. Body fat percentage is used by personal trainers and health professionals to get a more accurate look at your overall body composition. Because muscle weighs more than fat, regular weight measurements may create confusing conclusions about a person's body health.
Formula for Calculating Caloric Needs
Step 1
Enter information about your age, height and weight into one of the following gender-specific equations to calculate your BMR, using a calculator. For men, BMR = 66 + (6.23 x weight in pounds) + (12.7 x height in inches) - (6.8 x age in years). For women, BMR = 655 + (4.35 x weight in pounds) + (4.7 x height in inches) - ( 4.7 x age in years ).
Step 2
Multiply your BMR by one of the following activity level values from the Harris Benedict equation. For no exercise to light exercise 1 day per week, multiply by 1.2. For light exercise 1 to 3 days per week, multiply by 1.375. For moderate exercise 3 to 5 days per week, multiply by 1.55. For heavy exercise 6 to 7 days per week, multiply by 1.725 and for heavy exercise 7 days per week in addition to a physically demanding job, multiply by 1.9. The result is equal to the number of calories you need to consume each day to maintain your current weight.
Step 3
Adjust your total caloric requirements, found in Step 2, to meet your weight management goals. Or, use your body fat percentage to calculate your ideal caloric intake.
Body Fat Percentage
Step 1
Subtract your ideal body fat percentage from your current body fat percentage value to find your net change. For example, if you are at 30 percent and want to reach 25 percent, your body fat percentage change would be to drop 5 percent body fat.
Step 2
Multiply your answer from the previous step by your overall body weight to find how many pounds you need to lose. For example, if you weigh 200 lbs. and want to drop body fat by 5 percent, your goal for weight loss would equal 10 lbs.
Step 3
Set a realistic weight loss goal based on your rate of weight loss. MedlinePlus.com recommends consuming 500 fewer calories than you need, each day, to lose 1 lb. per week. To lose 2 lbs. per week, consume 1,000 calories fewer than you need, per day. For example, if you want to lose 20 lbs. at 2 lbs. per week, alter your diet and set a goal for achieving that loss in 10 weeks.
Tips and Warnings
- According to the American Council on Exercise, normal body fat for women is between 14 and 31 percent. For men, normal body fat is between 6 and 25 percent. Talk to your doctor about any significant weight management or dietary changes you are considering.
Things You'll Need
- Calculator
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