ENERGY
Food
is the fuel sources of body. The ingested food under goes metabolism to
librate energy required for the vital activities of the body.
Unit
of the energy :-
The
energy value of food has long been expressed in terms of Kcal. The kilo calori
is generally expressed as calorie (c).this has been accepted inter nationally.
The dietary sources of energy protein, fat and
carbohydrate. They supply energy at the following rates:-
v
Protein -4kcal/gm
v
Fat – 9kcal/gm
v
Carbohydrates-4kcal/gm.
Energy requirements :-
The energy requirement of an
individual may be defined as that level of energy intake in relation to
expenditure which is least rightly to result in obesity or heart diseases.
Actually the total energy requirement of an individual is made of three components:-
v
Energy require for basal metabolism
v
Energy require for daily activities
v
Energy expenditure occupational works.
Factor affecting energy
requirement
v
Gender :- male needs more energy
v
Age
v
Weight
v
Body temperature
v
External temperature
v
Hormones
v
Pregnancy and lactation
v
Disease condition
v
Physical activities
v
Fear and nervous system.
Measurements of energy
The amount of energy released from foods and
the amount of energy expended by an individual can be obtained by direct and
indirect calorimetry .
Direct
:-
The chemical change is that occurs when CHO or
fat oxidized during respiration in the
body or when this chemicals are burnt in the air is the underline principal on
which direct calorimetry. The amount of energy released or expended is measured
by heat produced. Indirect
method :-
It
is based on the principal that when an organic substances is completely from
combusted in the human body, oxygen is consumed in amount directly related to
energy liberated as heat.
Body
mass index (BMI) and basic metabolism :-
Body mass index is a simple index of weight
for height, that is commonly used to the classify under weight ,over weight or
obesity in adults. It is defined as the weight in kilograms derived by square
of height in meters(kg/m2)
Body mass index = W/H(M2).
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