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When the energy expenditure by our
body is exceeded by food energy intake, fat cells and at a
lesser degree muscle and liver cells throughout the body
absorb the energy and store it as fat. In our bodies, the
excess energy which is used to generate fat reserves is very
small when compared to total number of calories consumed. What
this means is that very minute changes in the energy balance
could lead to great fluctuations in weight over time.
In anatomical terms, fatty tissue is defined as adipose tissue
which are loose connective tissues composed of adipocytes.
Their main function is to store energy in the form of fat and
also cushion and insulate the body.
Obesity is a becoming a major concern in developed countries
like America where cheap fast food and sedentary lifestyles
are taking a serious toll and people’s health. Recent data
suggests that the situation is worsening and nearly 30% of
people 20 years and above i.e. nearly 60 million people are
obese.
Being obese puts one at great risk from many life threatening
health conditions such as Hypertension, Dyslipidemia, type 2
Diabetes, Coronary heart disease, Stroke, Gallbladder disease,
Osteoarthritis, Sleep apnea and respiratory problems, and
cancers like endometrial, breast and colon. The presence of
one or more of these diseases in a patient are also factors
taken into account when making a clinical diagnosis if a
person is overweight.
Being overweight and being obese are identified as ranges of
weight which are more than what is considered healthy for a
certain height. Weight and height are used to calculate a
number called “Body mass index” or “BMI” which will determine
if an individual is obese or just overweight. Therefore an
adult who has a BMI between 25 and 29.9 is considered
overweight and an adult who has a BMI of 30 or higher is
considered obese.
An important point to remember is that though BMI correlates
to body weight, it does not directly measure body fat.
Therefore, for e.g. athletes may have a BMI which suggests
that they are overweight though they may not have any excess
body fat.
Waist to hip ratio (≥0.9 for men and ≥0.85 for women) and
absolute waist circumference are also used to calculate
central obesity. Another method used to determine whether a
person is obese is to assess percent body fat. There is
general agreement among experts that men with more than 25%
body fat and women with more than 30% body fat are considered
obese. Other methods used to determine excess body fat are the
skinfold test where a pinch of kin is precisely measured in
order to determine the thickness of the subcutaneous fat layer
and the bioelectrical impedance analysis which is carried out
only in specialized clinics. Weighing a person underwater is
another method used though it is limited to laboratories with
special equipment.
Though it must be stressed that it difficult to precisely
measure body fat.
Researchers have found that there are various factors which
can cause a person to become overweight namely diet and level
of physical activity which in turn are influenced by the
personal characteristics of the individual, the environment
around him, cultural attitudes of his community and of course
his financial situation.
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