BASAL METABOLIC RATE (BMR) and BASAL METABOLIC INDEX (BMI) All energy is provided by three classes of nutrients: Macronutrients Fats Carbohydrates Protein Ethanol provide energy in some diets Energy production can be measured Heat output from the body Amount of O2 consumed It is calculated from the heat released by the total combustion of food in a calorimeter It is expressed in kilocalories (kcal, or Cal) The energy generated by metabolism is used for three energy-requiring processes: Resting metabolic rate (RMR) Physical activity Thermic effect of food Total Energy Expenditure (TEE): The number of calories expended by these processes in a 24-hour period

1. BASAL METABOLIC RATE (BMR)
and
BASAL METABOLIC INDEX (BMI)
Maryam Fida (o-1827)

2. Energy Production in body
 All energy is provided by three classes of nutrients:
Macronutrients
Fats
Carbohydrates
Protein
Ethanol provide energy in some diets
Energy production can be measured
1. Heat output from the body
2. Amount of O2 consumed

4. Energy content of food
It is calculated from the heat released
by the total combustion of food in a
calorimeter
It is expressed in kilocalories (kcal, or
Cal)

5. Calorimeter

6. Use of food energy in the body
The energy generated by metabolism is
used for three energy-requiring
processes:
1. Resting metabolic rate (RMR)
2. Physical activity
3. Thermic effect of food
 Total Energy Expenditure (TEE): The
number of calories expended by these
processes in a 24-hour period

7. Resting Metabolic Rate (RMR) or
Basal Metabolic Rate (BMR)
It is the energy expenditure by the body
At rest, Awake, Under controlled condition
In terms of O2 consumed or CO2 produced
Measured at post-absorptive state (12
hours after meal)
Measured in Kcal/hr/m2

8. Normal BMR values
Age BMR Value
New born baby 25 Kcal/hr/m2
Premature baby 20-22 Kcal/hr/m2
Upto 6 years 45 Kcal/hr/m2
Adult male 40 Kcal/hr/m2
Adult Female 37 Kcal/hr/m2

9. Factors affecting BMR
1. Weight
 More weight  more tissues  more metabolism More BMR
2. Age
 Decreases with age, in old age less active
3. Gender
 Women have lower BMR than Men
 Reason is Hormonal differences, body composition difference
4. Level of physical activity
 More activity High BMR
 Less Activity  Less BMR
5. Weather conditions
 High Temperature  More BMR
 Low Temperature  Less BMR
6. Fever
 High BMR

10. BMR
If there is a 5-10 % change from standard
BMR values, then it is ignored
But if more change  Dangerous
For example, A male has BMR= 51.5 Kcal/hr
Normal BMR= 40Kcal/hr
Difference is more than 5-10 % (11.5 Kcal)
Thyroxin is the hormone responsible for
High BMR

11. Hyperthyroidism
Thyroxin Secretion is more
So more metabolic activity
More O2 consumption
High BMR
People with high BMR never gain weight
They have high BP, high respiration
rate, high heart beat

12. Hypothyroidism
Less Thyroxin secretion
Less metabolic activity
Less O2 consumption
Low BMR
People with hypothyroidism are usually
obese (fat)
Have less BP, Less HR, less RR

13. Basal Metabolic Index (BMI)
Used for the assessment of obesity
An indirect measure, the body mass
index (BMI)
Measuring the waist size
In men, waist size ≤ 40 inches
In women, Waist size ≤ 35 inches
If more than 40 and 35, risk factor for
CHD

14. BMI
BMI = (weight in kg)/(height in meters)2
The healthy range for the BMI is
between 18.5 and 24.9
Overweight= 25 and 29.9 BMI
Obese= more than 30 BMI
Extremely Obese =more than 40 BMI
Severely obese = More than 100 pounds

17. Anatomic differences in fat deposition