Overview
of Obesity
Overweight
and obesity together represent the second leading
preventable cause of death in the United States.
Obesity is a serious, chronic disease that can
inflict substantial harm to a person’s health.
Over weight and obesity are not the same; rather,
they are different points on a continuum of weight
ranging from being underweight to being morbidly
obese. The percentage of people who fit into these
two categories, overweight and obese, is determined
by Body Mass Index (BMI).
The
US Surgeon General has declared that overweight
and obesity have reached epidemic proportions
in this country. Fifteen percent of children between
the ages of six and 19 are overweight. Public
health officials say physical inactivity and poor
diet are catching up to tobacco as a significant
threat to health. Currently, about 33 percent
of women and 28 percent of men are considered
seriously overweight. Obesity is a serious, chronic
disease that can inflict substantial harm to a
person's health.
BMI
is a measure of weight proportionate to height.
BMI is considered a useful measurement of the
amount of body fat. Occasionally, some very muscular
people may have a BMI in the overweight range.
However, these people are not considered overweight
because muscle tissue weighs more than fat tissue.
Generally, BMI can be considered an effective
way to evaluate whether a person is overweight
or obese.
According
to the National Heart, Lung, and Blood Institute
(NHLBI), a BMI from 18.5 to 24.9 is considered
normal while a BMI of more than 25 is considered
overweight. A person is considered obese if the
BMI is greater than 30 and morbidly obese if the
BMI is 40 or greater. In general, after the age
of 50, a man's weight stabilizes and even
drops slightly between the ages of 60 and 74.
However, a woman's weight continues to increase
until age 60 and then begins to drop.
Another
measure of obesity is the waist-to-hip ratio (WHR).
The WHR is a measurement tool that looks at the
proportion of fat stored on the waist, and hips
and buttocks. The waist circumference indicates
abdominal fat. A waist circumference over 40 inches
in men and over 35 inches in women may increase
the risk for heart disease and other diseases
associated with being overweight.
Consult
your physician with questions regarding healthy
body weight.
In many
ways, obesity is a puzzling disease. How the body
regulates weight and body fat is not well understood.
On one hand, the cause appears to be simple in
that if a person consumes more calories than he
or she expends as energy, then he or she will
gain weight.
However,
the risk factors that determine obesity can be
a complex combination of genetics, socioeconomic
factors, metabolic factors, and lifestyle choices,
as well as other factors. Some endocrine disorders,
diseases, and medications may also exert a powerful
influence on an individual's weight.
Factors
which may influence the occurrence of obesity
include, but are not limited to, the following:
- genetics - Studies
have shown that a predisposition toward obesity
can be inherited. The chance of being overweight
increases by 25 percent if one or both parents
are obese. Where a person carries weight - the
hips or around the middle - is also strongly
influenced by heredity.
- metabolic factors
- How a particular person expends energy is
different from how someone else's body uses
energy. Both metabolic and hormonal factors
are not the same for everyone, but these factors
play a role in determining weight gain. Recent
studies show that levels of ghrelin, a peptide
hormone known to regulate appetite, and other
peptides in the stomach, play a role in triggering
hunger and producing a feeling of fullness (satiety).
- socioeconomic factors
- There is a strong relationship between economic
status and obesity, especially among women.
Women who are poor and of lower social status
are six times more likely to be obese than women
of higher socioeconomic status. The occurrence
of obesity is also highest among minority groups,
especially among women. Seventy seven percent
of African-American women 20 years old
or older are overweight.
- lifestyle choices
- Overeating, along with a sedentary lifestyle,
contributes to obesity. These are lifestyle
choices that can be affected by behavior change.
Eating a diet in which a high percentage of
calories come from sugary, high-fat, refined
foods promotes weight gain. And, as more US
families eat on the go, high-calorie foods and
beverages are often selected.
Lack of regular exercise contributes to obesity
in adults and makes it difficult to maintain
weight loss. In children, inactivity, such as
watching television or sitting at a computer,
contributes to obesity.
Obesity
has a far-ranging negative effect on health. Each
year obesity-related conditions cost over 100
billion dollars and cause an estimated 300,000
premature deaths in the US. The health effects
associated with obesity include, but are not limited
to, the following:
- high blood pressure
- Additional fat tissue in the body needs oxygen
and nutrients in order to live, which requires
the blood vessels to circulate more blood to
the fat tissue. This increases the workload
of the heart because it must pump more blood
through additional blood vessels. More circulating
blood also means more pressure on the artery
walls. Higher pressure on the artery walls increases
the blood pressure. In addition, extra weight
can raise the heart rate and reduce the body's
ability to transport blood through the vessels.
- diabetes - Obesity
is the major cause of type 2 diabetes. This
type of diabetes begins in adulthood. Obesity
can cause resistance to insulin, the hormone
that regulates blood sugar. When obesity causes
insulin resistance, the blood sugar becomes
elevated. Even moderate obesity dramatically
increases the risk of diabetes.
- heart disease - Atherosclerosis
(hardening of the arteries) is present 10 times
more often in obese people compared to those
who are not obese. Coronary artery disease is
also more prevalent because fatty deposits build
up in arteries that supply the heart. Narrowed
arteries and reduced blood flow to the heart
can cause chest pain (angina) or a heart attack.
Blood clots can also form in narrowed arteries
and cause a stroke.
- joint problems, including
osteoarthritis - Obesity can affect the knees
and hips because of the stress placed on the
joints by extra weight. Joint replacement surgery,
while commonly performed on damaged joints,
may not be an advisable option for an obese
person because the artificial joint has a higher
risk of loosening and causing further damage.
- sleep apnea and respiratory
problems - Sleep apnea, which causes people
to stop breathing for brief periods, interrupts
sleep throughout the night and causes sleepiness
during the day. It also causes heavy snoring.
Respiratory problems associated with obesity
occur when added weight of the chest wall squeezes
the lungs and causes restricted breathing. Sleep
apnea is also associated with high blood pressure.
- cancer - In women,
being overweight contributes to an increased
risk for a variety of cancers including breast,
colon, gallbladder, and uterus. Men who are
overweight have a higher risk of colon and prostate
cancers.
- metabolic syndrome
- The National Cholesterol Education Program
has identified metabolic syndrome as a complex
risk factor for cardiovascular disease. Metabolic
syndrome consists of six major components: abdominal
obesity, elevated blood cholesterol, elevated
blood pressure, insulin resistance with or without
glucose intolerance, elevation of certain blood
components that indicate inflammation, and elevation
of certain clotting factors in the blood. In
the US, approximately one-third of overweight
or obese persons exhibit metabolic syndrome.
- psychosocial effects
- In a culture where often the ideal of physical
attractiveness is to be overly thin, people
who are overweight or obese frequently suffer
disadvantages. Overweight and obese persons
are often blamed for their condition and may
be considered to be lazy or weak-willed. It
is not uncommon for overweight or obese conditions
to result in persons having lower incomes or
having fewer or no romantic relationships. Disapproval
of overweight persons expressed by some individuals
may progress to bias, discrimination, and even
torment.
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