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Bariatric Surgery

What is Obesity?

Obesity is a disease of excess body fat. It is a poorly understood, chronic, metabolic disease that is caused by multiple factors, such as the following:

  • excessive food and calorie intake
  • decreased physical activity
  • genetic or inherited causes
  • medical conditions
  • environmental and social conditions
  • medications (antidepressants, steroids, insulin and other medications to manage diabetes mellitus)

A person's "body mass index" or BMI determines obesity and its severity.  Calculate your BMI from your height and weight using our online BMI calculator

Severe obesity (also known as morbid obesity) is the medical term used to describe obesity and its associated health problems. The word "morbid" means causing disease or injury. Severe obesity can affect nearly every organ in the body in some way, and it can cause serious illnesses, some of which are life-threatening.

The death rate associated with excess weight increases as the degree of obesity (excess weight) increases. It is estimated that between 280,000 and 325,000 deaths could be attributed to obesity annually in the United States. Life expectancy decreases as weight increases, especially in the severely obese:

  • Young women with BMIs of 45 or more have up to an 8-year reduction in life expectancy compared with women with normal BMIs.
  • Young men with BMIs of 45 or more have up to a 20-year decrease in life expectancy compared with men with normal BMIs.

Health Effects of Severe Obesity
The health effects of severe obesity include the following:

Diabetes Mellitus - Type 2

Obesity is the greatest risk factor for development of type 2 diabetes mellitus. Obese individuals develop a resistance to insulin, which regulates blood sugar levels.

The risk of type 2 diabetes mellitus increases with adult weight gain, the degree and duration of being overweight, and with a more central (abdominal) distribution of body fat. Overweight persons are 10 times more likely to develop Type 2 diabetes than those with an ideal BMI.

Over time, elevated blood sugar leads to serious damage throughout the body: heart disease, kidney failure, stroke, blindness, and arterial blockage resulting in amputations. Type 2 diabetes used to be called adult-onset diabetes, but obese children and adolescents are now afflicted with this disease.

Heart and Blood Vessel Disease

Obesity is a risk factor for heart and blood vessel diseases. Heart diseases promoted by obesity include:

  • sudden cardiac death
  • coronary artery disease
  • myocardial infarction (heart attack)
  • angina (cardiac chest pain)
  • abnormal cardiac (heart) rhythms
  • cardiomyopathy (enlarged weak heart)
  • congestive heart failure

Excess body weight strains the ability of the heart to function properly. Severely obese persons are 6 times more likely to develop heart disease than those who are normal weight.

Increased load on the heart leads to early development of congestive heart failure.

Severely obese persons are 40 times more likely to suffer sudden death than those with a ideal BMI. Obesity is also a risk factor in the development of cerebrovascular accidents (strokes).

High Blood Pressure

Elevated blood pressure, or hypertension, is much more common in people who are obese. Blood pressure increases as weight increases. Hypertension can lead to the development, and worsening, of heart disease, kidney disease, stroke and arterial blockage.

High Cholesterol and Lipid Levels

Cholesterol and triglyceride levels are commonly elevated in the severely obese: another factor predisposing to development of heart disease, blood vessel disease, and high blood pressure.

Venous Stasis Disease

The veins of the legs carry blood back to the heart through one-way valves. The pressure and weight of a heavy abdomen may damage these veins and valves. Legs can become swollen, and the skin can become thickened, discolored, and ulcerated. This also may lead to life-threatening blood clots in the legs.

Breathing Problems

Obesity can cause patients to be “out of breath” after minor physical activity. The increased weight leads to a heavy chest wall, poor breathing motion, decreased lung expansion, and poor oxygenation. This can interfere with normal daily physical activities such as housework, shopping, yardwork, or stair climbing. The shortness of breath may prevent patients from exercising and can be completely disabling. Obesity is also a major risk factor for asthma.

Sleep Apnea
Obesity is the most common risk factor for this life-threatening problem. Obstructive sleep apnea - the stoppage of breathing during sleep - is commonly caused by fatty tissue in the tongue and neck, which blocks the breathing passages. Patients may experience multiple, even hundreds, of upper airway obstructions during sleep. Patients who have sleep apnea may be unaware of their functional deterioration. Symptoms during sleep (usually reported by a spouse) include loud snoring, gasping, and witnessed apneas (stoppage of breathing). Loss of sleep often results in daytime drowsiness and headaches. The health effects of this condition may be severe: pulmonary hypertension, high blood pressure, cardiac rhythm disturbances, and sudden death.

Obesity Hypoventilation Syndrome
Obesity hypoventilation syndrome (OHS) typically occurs in people weighing more than 350 pounds. It manifests as severe shortness of breath while awake, even while resting. It is characterized by episodes of drowsiness or falling asleep during normal waking hours. OHS is caused by abnormalities of breathing and accumulation of toxic levels of carbon dioxide in the blood. Patients with OHS often have severe sleep apnea as well. These people are unable to get enough oxygen for their organs and tissues. This condition may result in heart failure, respiratory failure, blood clots, and death.

Digestive and Liver Problems

Obesity can lead to problems with the digestive system and liver.

Gastroesophageal Reflux Disease
Obese patients commonly have symptoms of heartburn and gastroesophageal reflux disease due to increased abdominal pressure.

Gallbladder Disease
Gallbladder disease and gallstones occurs more commonly in obese patients. When stones form in the gallbladder and cause abdominal pain, infection, or jaundice, the gallbladder should be removed.

Liver Disease
Obese patients often store excess amounts of fat within the liver, which damages the liver. Nonalcoholic fatty liver disease is increasingly being recognized as an important cause of liver-related disease and death, and it can lead to cirrhosis (scarring) of the liver. More than 80% of candidates for bariatric surgery have evidence of fatty liver changes.

Degenerative Joint Disease (Osteoarthritis) of Back, Hips, Knees, and Ankles

Obesity is a risk factor in the development of both arthritis and gout.
The osteoarthritis that develops in the hips, knees, and ankles is related to the excess ‘‘wear and tear’’ on these weight-bearing joints due to the excess body weight. Bones and muscles of the back can be strained and result in back disc problems, pain, and decreased mobility. Eventually, hip and knee joint replacement surgery may be needed.

Unfortunately, joint replacement has much poorer results in obese patients and many orthopedic surgeons require severely overweight patients to lose weight prior to joint replacement surgery. Obesity also increases osteoarthritis in non-weight-bearing joints such as the hands and wrists.

Menstrual/Reproductive Problems

Morbidly obese women often experience menstrual cycle irregularities and fertility problems due to the interaction of female hormones and fat cells. Obese women who do become pregnant are at a higher risk of complicated pregnancies. Obese women are at increased risk of cesarean delivery, preeclampsia (toxemia of pregnancy), eclampsia (convulsions), difficult labor and deliveries, and abnormally large newborns. These risks increase as the body mass index rises.

Stress Urinary Incontinence

Obese women, especially after childbirth, often experience leakage of urine with coughing, sneezing, or laughing. This is due to the increased abdominal pressure of their excess abdominal weight.


Obesity has been shown to be a major risk factor for cancer. It is estimated that approximately 14% to 20% of cancer deaths are directly attributable to underlying obesity. Obese men and women are at an increased risk of death from colon cancer, rectal cancer, esophageal cancer, liver cancer, pancreatic cancer, gallbladder cancer, and renal cell (kidney) cancer. Obese women are at an increased risk of cancer of the uterus, cervix, ovary, and breast. Obese men also have an increased risk of prostate cancer compared to normal weight men. It is estimated that over 90,000 cancer deaths per year in the United States could be avoided if the adult population maintained a normal weight.

Neurological/Psychological/Social Problems

Obesity can cause neurological problems such as pseudotumor cerebri and psychological/social problems.

Pseudotumor Cerebri
Pseudotumor cerebri is a neurological disorder that is characterized by increased intracranial pressure (pressure inside the head), in the absence of a tumor or other brain disease. Pseudotumor cerebri most commonly affects overweight women who are between ages 15 and 45. Symptoms include papilledema (swelling of the optic nerves), headache, tinnitus (ear ringing), visual disturbances (e.g., seeing double), and nausea/vomiting. Without weight loss, the treatment usually involves placing a surgical drain to decompress the fluid in the spine and the brain. After weight loss surgery, patients may become free of symptoms.

Psychosocial Function
Depression and anxiety are very common in obese patients. Patients often have poor self-image and are socially isolated. People who are overweight are often stigmatized and face public disapproval of their weight. This stigma occurs in education, employment, health care, and elsewhere. On average, obese people earn half as much as normal-weight people. Obese patients often experience discrimination, both in employment opportunities and social situations (such as fitting comfortably in theatre seats or riding in a bus or plane). All of these situations can lead to decreased quality of life and low self-esteem.

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