What Is The Suggested Calorie Intake For A Daily Diet?

The number of calories your body requires each day to maintain its current weight is a result of both your basal metabolic rate, or the amount of energy your body expends performing its basic vital functions, and your physical activity level. Your basal metabolic rate, in turn, is a result of your body composition, age and sex. While numerous health organizations provide estimates of caloric needs for males and females across all age groups, the most accurate way to determine your caloric needs is to calculate your BMR yourself.

BMR for Men

Men should calculate their BMR by multiplying their weight in lbs. by the number 6.23, height in inches by the number 12.7 and age in years by the number 6.8. Add the products of the first two calculations and then subtract the third from this sum. Add this outcome to the number 66 to obtain your BMR, or the number of calories you need to perform your basic vital functions. For example, a 45-year-old man who weighs 175 lbs. and measures 72 inches in height would have a BMR of about 1,765 calories.

BMR for Women

Women should calculate their BMR by multiplying their weight in lbs. by the number 4.35, their height in inches by the number 4.7 and their age in years by the number 4.7. Add the products of the first two calculations together, and then subtract the third from the sum. Add the result to the number 655 to obtain your BMR. For example, a 32-year-old-woman who weights 160 lbs. and measures 66 inches in height would have a BMR of about 1,511 calories.

Harris Benedict Equation

To determine your total caloric needs, you must account for your physical activity level using the Harris Benedict Equation. If you get little or no exercise, multiply your BMR by the number 1.2. If you get light exercise about one to three days per week, multiply your BMR by 1.375. If you get moderate exercise about three to five days per week, multiply your BMR by 1.55. If you get hard exercise about six to seven days a week, multiply your BMR by 1.725. If you exercise very hard seven days a week and are very active through your job, multiply your BMR by 1.9. For example, if the man above has a very active lifestyle, he would need about 3,350 calories each day to support his energy needs.

Macronutrient Calorie Intake

While it's important to know how many calories you need each day, you also need to obtain an optimal balance of the three macronutrients. According to the Food and Nutrition Board of the Institute of Medicine, about 45 to 65 percent of your calories should come from carbohydrates, 20 to 35 percent from fat and 10 to 35 percent from protein. The man described above would then need about 1,850 calories from carbohydrates, 1,000 from fat and 700 from protein each day.