| Obesity Causes |
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| Obesity is considered a
long-term complex disease. Many factors are involved in
determining why some people are heavier than others and how
much risk they have for developing other medical problems. |
| Science
continues to search for answers. But until the disease is better
understood, the control of excess weight is something patients
must work at for their entire lives. That is why 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 adverse effects
of excessive weight and alleviate the serious physical,
emotional and social consequences of the disease. |
| You
gain weight when you consume more calories from food than your
body uses through its normal functions (basal metabolic rate
[BMR]) and physical activity. The unused calories are stored as
fat. You become obese if you consistently consume excess
calories over a long period of time. For example, eating an
extra 100 calories per day can lead to a gain of about 10 lbs
(4.5 kgs) in a year. Gaining 10 pounds a year eventually will
result in a BMI of 30 or higher. |
| Your activity level is
also important. Activity uses calories, which helps balance the
calories you get through food. If you are inactive, it may be
easier to gain weight. |
| However, calories alone do not
explain weight gain and why some people gain (or lose) weight
more easily than others. Other factors that play a major role in
weight gain and obesity include: |
| Genetic or
Hereditary Factors |
Research has shown that in many
cases a significant underlying cause of morbid obesity is
genetic - you inherit the tendency to gain weight. Numerous
scientific studies have established that your genes play an
important role in your tendency to gain excess weight. The body
weight of adopted children shows no correlation with the body
weight of their adoptive parents who feed them and teach them
how to eat. Their weight does have an 80 percent correlation
with their genetic parents whom they have never met. 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. |
| Environmental
Factors |
| Environmental and genetic factors are
obviously closely intertwined. If you have a genetic
predisposition toward obesity, then the modern lifestyle and
environment that has readily available inexpensive food high in
fat and low in fruits and vegetables may lead to weight gain and
obesity. 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 by nonoperative measures. |
| Metabolism |
We
used to think of weight gain or loss as only a function of
calories ingested and then burnt. Take in more calories than you
burn and gain weight; burn more calories than you ingest and
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.
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