Assignment #3—Energy
Due by April 3, 2007
(45 points)
Answer the following questions regarding energy intakes (from your food diary)
and energy requirements. The tables in Appendix F may help you estimate your
physical activity level, etc.
1. Calculate your BMR using the equations in the table on the attached page. (Be sure to
indicate your age). (4 points)
2. Estimate your daily energy expenditure for 1 day. Look at the example
estimation/calculation on the attached page and follow it when calculating your own.
(8 points)
3. A) What was your average energy intake from your 3 day diet record? Compare this
to your energy expenditure as determined with the activity log. Are you in positive
energy balance, negative energy balance or in energy equilibrium? (3 points)
B) What is your RDA (EER) for energy? See the table on the front inside cover of
the text. (2 points)
C) The RDA for energy assumes average body weights shown below. Adjust your
energy RDA to your actual weight. (Remember 1 kg = 2.2 lbs) (5 points)
Men
Women
14-18 yr
61 kg
54 kg
19-30 yr
70 kg
57 kg
31-50 yr
77 kg
62 kg
D) Estimate your energy requirements by using the “How To” table on page 260 in
your text. First select a level of activity that is a good estimate for your average
daily level of physical activity and make the appropriate calculations. (5 points)
E) For this question, assume the following: all excess calories are stored as fat or
that all calories expended in excess of caloric intake come from the oxidation of
fat. Remember that fat contains 3500 kcal/pound. Using your energy expenditure
estimate from part (D) and your average caloric intake, determine how much
weight you would gain or lose in 60 days. (5 points)
F) Looking at all three estimates of your energy expenditure (2, 3c, 3d) which do
you think is most accurate and why? (5 points)
G) If someone was typically sedentary and decided to increase their regular physical
activity to a moderate level, how many additional kcals would they expend per
day? If their weight had been stable and they did not increase food consumption,
how much of a weight loss would this translate into over 30 days? Use the table
on page 260 again. (5 points)
4. A) Calculate your body mass index. BMI = mass in kg/height2. The units for height
are in meters2. (1 ft = .305 meters) (2 points)
B) What is the recommended range for BMI? (1 point)
Equations for Estimating BMR from Body Weight
Males
(Age in yrs)
Equations for deriving
BMR in kcal/day
Females
(age in years)
Equations for deriving
BMR in kcal/day
10-18
(17.5 x weight) + 651
10-18
(12.2 x weight) + 746
18-30
(15.3 x weight) + 679
18-30
(14.7 x weight) + 496
30-60
(11.6 x weight) + 879
30-60
(8.7 x weight) + 829
Sample calculations for estimating daily energy expenditure
First calculate your BMR. In general a good estimate for BMR is your weight in
kilograms * 24. Of course your hourly BMR would simply be your weight in kg. In the
book you will also find equations for estimating BMR. Regardless of which equation
you use to determine your BMR, divide it by 24 hours to determine your hourly BMR.
Example: if BMR = 1440 kcal/day, dividing by 24 hours gives an hourly BMR of 60
kcal/hr. Also, if you work out on a cardiovascular machine that calculates kcaloric
expenditure, you may use that value.
Activity
Category
Activity
Duration
(hours)
Resting
Sleeping/reclining
10
10 hr x 1.0 (from table) x
60 kcal/hr (BMR/hr)
600 kcal
Very light
Studying, watching TV, class,
cooking
10
10 * 1.5 * 60
900 kcal
Light
Cleaning house
1
1 * 3 * 60
180 kcal
Moderate
Walking
1
1 * 5 *60
300 kcal
Heavy
Aerobics/weights
1.5
1.5 * 7 * 60
630 kcal
Extremely
heavy
Running
.5
.5 * 15 *60
450 kcal
TOTAL
24
Calculation
Energy
expended
3060 kcal