Obesity results from the excessive accumulation of fat that exceeds
the body's skeletal and physical standards. Today 97 million Americans,
more than one-third of the adult population, are overweight or obese.
An estimated 5 to 10 million of those are considered morbidly obese.
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 in
significant physical disability or even death.
Causes of Obesity
In scientific terms, obesity occurs when a person consumes more
calories than he or she burns. What causes this imbalance between
calories in and calories out may differ from one person to another.
Genetic, environmental, psychological, and other factors may all
play a part.
Obesity tends to run in families, suggesting a genetic cause. Yet
families also share diet and lifestyle habits that may contribute
to obesity. Separating these from genetic factors is often difficult.
Even so, science shows that heredity is linked to obesity. In one
study, adults who were adopted as children were found to have weights
closer to their biological parents than to their adoptive parents.
In this case, the person's genetic makeup had more influence on
the development of obesity than the environment in the adoptive
Genes do not destine people to a lifetime of obesity, however. Environment
also strongly influences obesity. This includes lifestyle behaviors
such as what a person eats and his or her level of physical activity.
Americans tend to eat high-fat foods, and put taste and convenience
ahead of nutrition. Also, most Americans do not get enough physical
activity. Although you cannot change your genetic makeup, you can
change your eating habits and levels of activity. Try these techniques
that have helped some people lose weight and keep it off:
- Learn how to choose more nutritious meals that are lower in fat.
- Learn to recognize and control environmental cues (like inviting smells)
that make you want to eat when you're not hungry.
- Become more physically
- Keep records of your food intake and physical activity.
Psychological factors may also influence eating habits. Many people
eat in response to negative emotions such as boredom, sadness, or
anger. Most overweight people have no more psychological problems
than people of average weight. Still, up to 10 percent of people
who are mildly obese and try to lose weight on their own or through
commercial weight loss programs have binge eating disorder. This
disorder is even more common in people who are severely obese. During
a binge eating episode, people eat large amounts of food and feel
that they cannot control how much they are eating. Those with the
most severe binge eating problems are also likely to have symptoms
of depression and low self-esteem. These people may have more difficulty
losing weight and keeping it off than people without binge eating
problems. If you are upset by binge eating behavior and think you
might have binge eating disorder, seek help from a health professional
such as a psychiatrist, psychologist, or clinical social worker.
Other causes of obesity:
Some illnesses can lead to obesity or a tendency to gain weight.
These include hypothyroidism, Cushing's syndrome, depression, and
certain neurological problems that can lead to overeating. Also,
drugs such as steroids and some antidepressants may cause weight
gain. A doctor can tell whether there are underlying medical conditions
that are causing weight gain or making weight loss difficult.
Body Mass Index
Everyone needs a certain amount of body fat for stored energy, heat
insulation, shock absorption, and other functions. As a rule, women
have more body fat than men. Most health care providers agree that
men with more than 25 percent body fat and women with more than
30 percent body fat are obese. Because measuring a person's body
fat is difficult, health care providers often rely on other means
to diagnose obesity. Weight-for-height tables, which have been used
for decades, usually have a range of acceptable weights for a person
of a given height. One problem with these tables is that there are
many versions, all with different weight ranges. Another problem
is that they do not distinguish between excess fat and muscle. A
very muscular person may appear obese, according to the tables,
when he or she is not. In recent years, body mass index (BMI) has
become the medical standard used to measure overweight and obesity.
BMI uses a mathematical formula based on a person's height and weight.
BMI equals weight in kilograms divided by height in meters squared
(BMI = kg/m2). The BMI table that follows has already calculated
this information. Although the BMI ranges shown in the table are
not exact ranges of healthy and unhealthy weight, they are useful
guidelines. A BMI of 25 to 29.9 indicates a person is overweight.
A person with a BMI of 30 or higher is considered obese. Like the
weight-to-height table, BMI does not show the difference between
excess fat and muscle. BMI, however, is closely associated with
measures of body fat. It also predicts the development of health
problems related to excess weight. For these reasons, BMI is widely
used by health care providers.
Calculate your BMI
Consequences of Obesity
Weight loss is not a cure for eating disorders. And there are medical
conditions, such as hyperthyroidism, that can also cause weight
gain. It's important to work with your doctor to make sure that
you do not have a condition that should be treated with medication
Co-morbidities are health conditions, which whether alone or in
combination, can significantly reduce your life expectancy. A partial
list of common conditions follows.
- Diabetes: Obese individuals develop a resistance to
insulin, which regulates blood sugar levels. Over time, the resulting
high blood sugar can cause serious damage to the body.
- High blood pressure/Heart disease: Excess body weight
strains the ability of the heart to function properly. The resulting
hypertension (high blood pressure) can result in strokes, as well
as inflict significant heart and kidney damage.
- High cholesterol: Elevation of lipids and triglycerides
in the blood, which contributes to early heart disease, blood
vessel disease and stroke.
- Sleep apnea/Respiratory problems: Fat deposits in the
tongue and neck can cause intermittent obstruction of the air
passage. Because the obstruction is increased when sleeping on
your back, you may find yourself waking frequently to reposition
yourself. The resulting loss of sleep often results in daytime
drowsiness and headaches.
- Gastroesophageal reflux/Heartburn: Acid belongs in the
stomach and seldom causes any problem when it stays there. When
acid escapes into the esophagus through a weak or overloaded valve
at the top of the stomach, the result is called gastroesophageal
reflux, and heartburn and acid indigestion are common symptoms.
Approximately 10-15% of patients with even mild sporadic symptoms
of heartburn will develop a condition called Barrett's esophagus,
which is a pre-malignant change in the lining membrane of the
esophagus, a cause of esophageal cancer.
- Osteoarthritis of weight-bearing joints: The additional
weight placed on joints, particularly knees and hips, results
in rapid wear and tear, along with pain caused by inflammation.
Similarly, bones and muscles of the back are constantly strained,
resulting in disk problems, pain and decreased mobility.
- Gallbladder disease: The formation of gallstones within
the gallbladder, which can lead to symptoms of severe abdominal
pain, nausea and vomiting.
- Menstrual irregularities: Morbidly obese individuals
often experience disruptions of the menstrual cycle, abnormal
menstrual flow and increased pain associated with the menstrual
- Infertility/Pregnancy complications: The inability or
diminished ability to produce offspring or maintain a healthy
- Urinary stress incontinence: A large, heavy abdomen
and relaxation of the pelvic muscles, especially associated with
the effects of childbirth, may cause the valve on the urinary
bladder to be weakened, leading to the leakage of urine with coughing,
sneezing or laughing.
- Depression: Seriously overweight persons face constant
challenges to their emotions: repeated failure with dieting, disapproval
from family and friends, sneers and remarks from strangers. They
often experience discrimination at work, cannot fit comfortably
in theatre seats, or ride in a bus or plane.
- Increased surgical risks: Obese individuals are at high
risk for surgical complications because they may be experiencing
medical problems listed above.