Essentials of Anatomy and Physiology

Body Temperature and Metabolism 411

BOX17–4 METABOLIC RATE

Example:A 160-pound man:

1. 160 lb at 2.2 lb/kg = 73 kg


2. 73 kg x 1.0 kcal/kg/hr = 73 kcal/hr


3. 73 kcal/hr x 24 = 1752 kcal/day
   To approximate the amount of energy actually
   expended during an average day (24 hours), the
   following percentages may be used:
   Sedentary activity: add 40% to 50% of the BMR to
   the BMR
   Light activity: add 50% to 65% of the BMR to the
   BMR
   Moderate activity: add 65% to 75% of the BMR to
   the BMR
   Strenuous activity: add 75% to 100% of the BMR to
   the BMR
   Using our example of the 120-pound woman
   with a BMR of 1200 kcal/day:
   Sedentary: 1680 to 1800 kcal/day
   Light: 1800 to 1980 kcal/day
   Moderate: 1980 to 2100 kcal/day
   Strenuous: 2100 to 2400 kcal/day

To estimate your own basal metabolic rate

(BMR), calculate kilocalories (kcal) used per hour as

follows:

For women: use the factor of 0.9 kcal per kilogram

(kg) of body weight

For men: use the factor of 1.0 kcal per kg of body

weight

Then multiply kcal/hour by 24 hours to determine

kcal per day.

Example:A 120-pound woman:

1. Change pounds to kilograms:
   120 lb at 2.2 lb/kg = 55 kg


2. Multiply kg weight by the BMR factor:
   55 kg x 0.9 kcal/kg/hr = 49.5 kcal/hr


3. Multiply kcal/hr by 24:
   49.5 kcal/hr x 24 = 1188 kcal/day
   (An approximate BMR, about 1200
   kcal/day)

BOX17–5 WEIGHT LOSS

food. Keeping track of daily caloric intake is an

important part of a decision to try to lose weight. It

is also important to remember that sustained loss of

fat usually does not exceed 1 to 2 pounds per week.

In part this is so because as calorie intake decreases,

the metabolic rate decreases. There will also be loss

of some body protein so that amino acids can be

converted to carbohydrates to supply the brain.

A sensible weight-loss diet will include carbohy-

drate to supply energy needs, will have sufficient

protein (40 to 45 grams per day), and will be low in

animal fat. Including vegetables and fruits will sup-

ply vitamins, minerals, and fiber.

Although diet books are often found on the best-
seller lists, there is no magic method that will result
in weight loss. Losing weight depends on one sim-
ple fact: calorie expenditure in activity must exceed
calorie intake in food (the term caloriehere will be
used to mean kilocalorie).
To lose 1 pound of body fat, which consists of fat,
water, and protein, 3500 calories of energy must be
expended. Although any form of exercise requires
calories, the more strenuous the exercise, the more
calories expended. Some examples are shown in the
accompanying table.
Most food packaging contains nutritional infor-
mation, including the calories per serving of the
Calories per 10 Calories per 10
minutes(average minutes(average
Activity for a 150-lb person) Activity for a 150-lb person)

Walking slowly

Walking briskly

Walking up stairs

Dancing (slow)

Dancing (fast)

30

45

170

40

65

Running (8 mph)

Cycling (10 mph)

Cycling (15 mph)

Swimming

120

70

115

100