1. Estimate your basic energy needs.
You can use one of two methods: Multiply your current weight (in pounds) by 10 if you're a woman or lilt you're a man. Or use the formula in Table, which factors in your age in addition to your sex.
In the formula, weight represents your weight in kilograms, so translate your weight into kilograms by dividing the number of pounds you weigh by 2.2.
| Age | Use This Equation to Calculate Your BMR |
| Men | |
| 18 to 30 | |
| 30 to 60 | |
| Older than 60 | |
| |
| 18 to 30 | |
| 30 to 60 | |
| Older than 60 | |
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 + 8'l9 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 BMX 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.
2. Determine your activity factor value.
How active are you? Find the description in Table 8-2 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?
Sitting or standing; driving; painting; doing laboratory work; sewing, ironing, or cooking; playing cards or a musical instrument; sleeping or lying down; reading; typing
Your Activity Level: Very Light
Your Activity Factor: 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
Your Activity Level: Light
Your Activity Factor: 0.3
Heavy gardening or housework, cycling, playing tennis, skiing, or dancing; very little sitting
Your Activity Level: Moderate
Your Activity Factor: 0.4
Heavy manual labor such as construction work or digging; playing sports such as basketball, football, or soccer; climbing
Your Activity Level: Heavy
Your Activity Factor: 0.5
3. Multiply your basic energy needs by the activity factor value
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
4. 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.
1,442 calories + 432.6 calories = 1874.6 x 10% = 187.5 calories
5. 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
