We all enjoy the variety of food that
tantalizes our taste-buds. However, food performs other important
functions in our body besides pampering our tongue. It is essential for
survival, growth , cell reproduction and maintaining good health. Food
is the fuel which supplies chemical energy to our body to support daily
activities and growth. Apart from energy, food provides us with
proteins, carbohydrates, fats, vitamins, minerals and fiber. All these
nutrients are required by our body in certain specific amounts and a
deficiency or excess of any of these can have adverse effects on our
What Is A “Calorie”?
A “Calorie” is a unit of measurement of energy. Physically, a
calorie is that amount of heat which is required to raise the
temperature of one gram of water by one degree Celsius. However,
“Joule” is also taken as a measuring unit for heat. The conversions
in relation to calorie are given below-
Practically, the term “calorie” is taken for measuring energy
contents of food stuffs. Not only this, but it is also used for
calculating the energy requirements of our body. Calories are needed to
sustain the basic operations of human body, while working as well as at
How Much Do You Need? The calorific requirement of an individual per day is
determined by these basic factors:
1. The Basal Metabolic Rate (BMR)- It is that amount of energy
which is required by the body to support vital bodily activities when we
are at rest like- respiration, blood circulation, digestion, absorption,
secretion of fluids, filtration, thought processes etc. The BMR
constitutes the majority of our calorie expense in a day.
2. The Thermic Effect of Food (TEF)- It is that amount of energy
which is required by the body to digest the eaten food and absorb its
3. The Active Metabolic Rate (AMR)- It is the energy required by
the body for performing a particular activity or a group of activities.
For any given activity, the number of calories that you expend depends
upon your body weight. Higher the body weight, the more calories are
expended. For e.g. while a 70 Kg. human being spends 20 cal. Per minute
pacing at about 6 mph. an 80 Kg. individual spends about 40 cal. Per
minute running at 6 mph.
Not only the body weight, the intensity with which an activity is
performed also makes a world of difference. You can thus obviously see
the difference between the energy needs of a person who walks relatively
fast than a person who just carries himself/herself around. Even two
athletes performing the same exercise require different amounts of
energy depending upon the intensity with which they are doing it.
4. The Life Cycle Stage of an individual- The daily calorific
requirement varies greatly with the age, gender, state of sickness or
well-being etc. For e.g. a lactating mother needs higher energy and so
does a growing child. While an aged person having no work to do at all
needs less of calories and so is the variation with sex where men need a
bit more energy than women do.
In the next part of the article we’ll discuss the sources of calories
and their individual effect on the human body.