[You can find other parts of the Obesity simplex 'series' further down or alternatively you can click on the painting in the top right hand corner]

1. BMR (basal metabolic rate)
Another useful quantity for your data base is your BMR. The BMR refers to the daily energy (caloric) expenditure resulting from all the involuntary activities that keep the body alive and warm.
About two thirds (say 67%) of an average person’s daily energy expenditure is linked to their basal metabolic rate (BMR).
The total daily energy expenditure can be derived from the BMR (see below)

You can estimate your BMR by making use of the Harris-Benedict equations for males and females respectively:

Males: BMR = 66 + (13.7 x weight in kg) + (5 x height in cm) – (6.8 x age in yr)

Females: BMR = 655 + (9.6 x weight in kg) + (1.8 x height in cm) – (4.7 x age in yr)

Example: Estimating Miss C. Green’s BMR

Weight = 79 kilograms (kg) – Height = 167.5 cm (1.675 metres) – Age = 28 yr

BMR= 655 + (9.6 x wt) + (1.8 x ht) – (4.7 x age)
= 655+ (9.6 x 79) + (1.8 x 167.5) – (4.7 x 28)
= 655 + 758.4 + 301.5 – 131.6
= 1583.3 = 1583 Calories (rounded off)

BMR per hour = 1583 divided by 24 = 65.95 Calories = 66 Calories

2. Total daily energy expenditure

We can estimate daily total energy expenditure from BMR thus:

Daily total energy expenditure = (BMR x 100) divided by 67

For Miss C. Green, total daily energy expenditure = (1583 x 100) divided by 67
= 2362 Calories
3. Total daily energy intake
Provided there is no change in the daily energy expenditure, there are 3 possibilities:
-If weight is more or less constant:
(a) energy intake = energy expenditure = 2362 Calories

-If weight changes (in practical terms from one week to the next):
(b) each pound gained represents a surplus intake of 3500 Calories
(c) each pound lost represents a reduced intake of 3500 Calories

For example a gain of 2 pounds in a week = a surplus of 7000 Calories (2 x 3500)
= a daily average surplus of 1000 Calories (7000 divided by 7)

Note that many women gain weight through water retention around the time of their menstrual period. Oral contraceptives may also have the same effect.