What Is Obesity?
Weight gain and obesity develops when the energy supplied
from the food and drink you consume is greater than the energy your
body needs for physical activity and other metabolic processes.
For example, in Australia a recent report estimated that approximately 60% of adults, aged 25 years and
over, are overweight or obese.
Severe or "Morbid" Obesity
Obesity becomes "morbid" when it reaches the point of significantly
increasing the risk of one or more obesity-related health conditions or serious
diseases (also known as co-morbidities) that result either in significant physical
disability or even death. Morbid obesity, also called "very severe obesity", is
typically defined as being 45 kg or more over ideal body weight or having a Body
Mass Index (BMI) of 40 or higher.
You can check your BMI using the chart below or use our
BMI
Calculator.
Health Risks of Morbid Obesity
Overweight and obesity is a serious, chronic medical condition, which
is associated with a wide range of chronic and debilitating illnesses such as diabetes, heart
disease, some cancers, sleep apnoea and osteoarthritis.
Morbid obesity brings with it an increased risk for a shorter
life expectancy. For individuals whose weight exceeds 50% above their ideal body
weight, the risk of an early death is doubled compared to non-obese individuals.
Causes of Overweight and Obesity
The following have been identified as important factors in the
development of overweight or obesity:
- Energy intake from food exceeds energy expenditure - but obesity is not simply a result of overeating
- Biological factors such as age, sex, hormonal and genetics
- Behavioural influences such as learnt habits, emotions, attitudes, beliefs and thought processes
- Environmental/societal influences such as social, political and economic environment
- Metabolism and the potential effects of a 'set point'
- Some medical conditions such as hypothyroidism
It is very important to understand that all current medical
interventions, including weight loss surgery,
should not be considered medical cures. Rather
they are attempts to reduce the effects of
excessive weight and alleviate the serious
physical, emotional and social consequences of morbid obesity.
Contributing Factors of Morbid Obesity
There are many factors that contribute to the development of
obesity including genetic, hereditary, environmental, metabolic and eating disorders.
There are also certain medical conditions that
may result in obesity like intake of steroids and hypothyroidism.
Biological Factors
Genetic factors, hormone factors, age and sex are all biological factors that have been identified to influence
body fat levels.
- Research conducted on Danish adoptees showed a strong relationship
between the Body Mass Index of their biological
parents and little, if any, correlation with
adopted parents. The authors concluded
that human obesity is under genetic control,
whereas the family environment had little
influence on obesity in adults.
- Identical twins, with the same genes, show a much higher similarity
of body weights than do fraternal twins, who have different genes.
- Certain groups of people, such as the Pima Indian tribe in Arizona,
have a very high incidence of severe obesity.
They also have significantly higher rates of
diabetes and heart disease than other ethnic groups.
We probably have a number of genes directly related to weight. Just
as some genes determine eye color or height,
others affect our appetite, our ability to feel
full or satisfied, our metabolism, our fat-storing
ability, and even our natural activity levels.
The Pima Paradox
The Pima Indians are known in scientific circles as one of the
groups of heaviest people in the world. In fact,
American researchers have been studying them for
more than 35 years. Some adults weigh more than 225
kg, and many obese teenagers are suffering from
diabetes, the disease most frequently associated
with morbid obesity.
But here's a really interesting fact - a group of Pima Indians
living in Sierra Madre, Mexico, does not have a
problem with obesity and its related diseases. Why not?
The leading theory states that after many generations of living in
the desert, often confronting famine, the most
successful Pima were those with genes that
helped them store as much fat as possible during
times when food was available. Now those fat-storing
genes work against them.
Though both populations consume a similar number of calories
each day, the Mexican Pima still live much like
their ancestors did. They put in 23 hours of
physical labor each week and eat a traditional
diet that's very low in fat. The Arizona Pima
live like most other modern Americans, eating a
diet consisting of around 40 percent fat and
engaging in physical activity for only two hours
a week.
The Pima apparently have a genetic predisposition to gain weight.
And the environment in which they live - the environment in which most of us live - makes it
nearly impossible for the Arizona Pima to maintain a normal, healthy body weight.
Environmental Factors
Environmental and genetic factors are obviously closely
intertwined. If you have a genetic
predisposition toward morbid obesity, then the
modern lifestyle and environment may
make controlling weight more difficult.
Fast food, long days sitting at a desk, and suburban
neighborhoods that require cars all magnify
hereditary factors such as metabolism and
efficient fat storage.
For those suffering from morbid obesity, anything less than a total
change in environment usually results in failure
to reach and maintain a healthy body weight.
Metabolism
We used to think of weight gain or loss as only a function of
calories ingested and then burned. Take in more
calories than you burn, gain weight; burn more
calories than you ingest, lose weight. But now
we know the equation isn't that simple.
Obesity researchers now talk about a theory called the "set
point", a sort of thermostat in the brain
that makes people resistant to either weight
gain or loss. If you try to override
the set point by drastically cutting your
calorie intake, your brain responds by lowering
metabolism and slowing activity. You then gain
back any weight you lost.
Eating Disorders & Medical Conditions
Weight loss surgery is not a cure for
eating disorders or morbid obesity. And there
are medical conditions, such as hypothyroidism,
that can also cause weight gain. That's why it's
important that you work with your doctor to make
sure you do not have a condition that should be
treated with medication and counseling. |
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