ENERGY COST OF PHYSICAL ACTIVITIES
Next to Basal Metabolism it is the physical activity, which accounts for the largest energy expenditure.
There is a wide variation from individual to individual in occupational activity.
The energy required for the actual physical activity varies depending on the type of occupation of an individual.
For computing energy requirements, the occupations have been classified as sedentary, moderate and heavy.
The ICMR classification of activities based on occupation is given in table-20C.
The energy cost of physical activities is expressed in terms of BMR units.
BMR Unit :
The energy cost of rest and physical activity is expressed as multiples of BMR which is called the physical activity ratio (PAR).
The physical activity ratio expresses the energy cost of an individual activity per minute as ratio of the cost of BMR per minute. Hence it is advantageous to express the energy expenditure in terms of BMR units.
THERMIC EFFECT OF FOOD
Food ingestion stimulates metabolism and requires energy to meet the multiple activities of digestion, absorption and
transport of nutrients. This overall stimulating effect of food is called dietary thermogenesis or thermic effect of food (formerly called as specific dynamic action (SDA). The increase in energy cost because of thermogenesis is 10%.