Dieting For Dummies
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Determining your body’s total dietary energy needs takes a bit of math — so grab a calculator. This method of determining your calorie needs is easier and almost as accurate as checking into a research lab and submitting yourself to scientific scrutiny by a white-coated nerd with a clipboard and a stopwatch.

  1. Estimate your basic energy needs.

    Multiply your current weight (in pounds) by 10 if you’re a woman or 11 if you’re a man. Or use the formula in table below, which factors in your age in addition to your sex.

    For example: Sue is a 45-year-old female who weighs 155 pounds. She calculates her BMR like this:

    155 pounds ÷ 2.2 = 70.45 kilograms

    70.45 kilograms x 8.7 = 612.92 calories

    612.92 calories + 829 calories = 1,441.92 calories

    So Sue’s BMR — or the number of calories that her body needs at complete rest to function — is roughly 1,442 calories.

    If you figure Sue’s BMR by using the shortcut method, her needs are about 1,550 (155 pounds x 10 = 1,550) — a bit higher than the full calculation, but still in the same ballpark.

How Many Calories Your Body Needs Per Day for Basic Energy Needs
Age Use This Equation to Calculate Your BMR
* Men
18 to 30 [15.3 x weight (in kilograms)] + 679
30 to 60 [11.6 x weight (in kilograms)] + 879
Older than 60 [13.5 x weight (in kilograms)] + 487
* Women
18 to 30 [14.7 x weight (in kilograms)] + 496
30 to 60 [8.7 x weight (in kilograms)] + 829
Older than 60 [10.5 x weight (in kilograms)] + 596
  1. Determine your activity factor value.

    How active are you? Find the description in the following table that best matches your lifestyle. If you have a desk job but fit in a dose of daily exercise (at least 30 minutes), consider yourself in the light or moderate category.

How Active Are You?
If, Throughout Most of Your Day, Your Activities Include Your Activity Level Is Your Activity Factor Is
Sitting or standing; driving; painting; doing laboratory work; sewing, ironing, or cooking; playing cards or a musical instrument; sleeping or lying down; reading; typing Very light 0.2
Doing garage, electrical, carpentry, or restaurant work; house-cleaning; caring for children; playing golf; sailing; light exercise, such as walking, for no more than 2 miles Light 0.3
Heavy gardening or housework, cycling, playing tennis, skiing, or dancing; very little sitting Moderate 0.4
Heavy manual labor such as construction work or digging; playing sports such as basketball, football, or soccer; climbing Heavy 0.5
  1. Multiply your basic energy needs by the activity factor value that you determined in Step

    Using Sue as an example, she multiplies her BMR of 1,442 by 0.3 because her activity level is light — running around after her kids, taking care of the house, and fitting in a 2-mile morning walk with her neighbors every other day. Sue needs 432.6 calories for her activity level.

    1,442 x 0.3 = 432.6 calories

  2. Determine the number of calories that you need for digestion and absorption of nutrients.

    Eating food actually burns calories. Digesting food and absorbing nutrients uses about 10 percent of your daily energy needs. Add together your BMR and activity calories and then multiply the total by 10 percent.

    The calculation for Sue’s calorie needs for digestion and absorption looks like this:

    1,442 calories + 432.6 calories = 1874.6 x 10% = 187.5 calories

  3. Total your calorie needs.

    Add together your BMR, activity, and digestion/absorption calorie needs to get your total calorie needs — that is, the number of calories that you need to maintain your current weight.

    To maintain her current weight of 155 pounds, Sue calculates her total calorie needs like this:

    1,442 calories + 432.6 calories + 187.5 calories = 2,062 total calories

About This Article

This article is from the book:

About the book authors:

Jane Kirby, RD is a registered dietitian and member of the American Dietetic Association. She is the food and nutrition editor of Real Simple magazine and owner of The Vermont Cooking School, IncTM in Charlotte, Vermont. Jane is the former editor of Eating Well magazine and the food and nuitrition editor for Glamour. She served on the dietetics staff of the Massachusettes General Hospital in Boston, where she  completed graduate work in nutrition. She holds a Bachelor of Science degree from Marymount College.

The American Dietetic Association is the world’s largest group of nutrition and health professionals. As an advocate of the profession, the ADA serves the public by promoting optimal nutrition, health, and well-being.

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