Defining Obesity

A clear definition of morbid obesity is very important because this definition is used to guide doctors in the selection of treatment options for people who are overweight. Individuals are usually considered morbidly obese if their weight is more than 80 to 100 pounds above their ideal body weight.

A more widely accepted and more exact way to define morbid obesity is with the body mass index (BMI). The BMI is calculated as follows:

BMI = weight (kg)/height (m2)

To find out what your BMI is click here.

A BMI above 40 indicates that a person is morbidly obese and therefore a candidate for bariatric surgery. Bariatric surgery may also be an option for people with a BMI between 35 and 40 who suffer from life-threatening cardiopulmonary problems, diabetes, or other medical problems listed below. However, as in other treatments for obesity, successful results can be affected by motivation and behavior.

People who are obese have higher rates of medical problems. The chance of problems such as heart disease, high blood pressure, diabetes, and premature death increases dramatically as weight increases. Morbidly obese men between the ages of 25 and 35 have a 12-fold greater risk of dying prematurely compared to people of the same age who are of normal weight.

Medical Conditions Commonly Caused By Obesity

  • Pulmonary (related to lungs) - obstructive sleep apnea, obesity hypoventilation syndrome, asthma/reactive airway disease
  • Cardiac (related to heart) - high blood pressure, heart failure caused by pulmonary hypertension, higher risk of coronary artery disease (atherosclerosis)
  • Gastrointestinal, abdominal - gallbladder disease, GERD (recurrent heartburn), recurrent ventral hernias, fatty liver
  • Endocrine - diabetes, hirsutism, hyperlipidemia, hypercholesterolemia
  • Genito-urinary, reproductive - frequent urinary tract infections (UTIs), stress, urinary incontinence, menstrual irregularity or infertility
  • Musculoskeletal - degeneration of knees and hips, disc herniation, chronic non-surgical low back pain
  • Skin - multiple disorders, most related to diabetes and yeast infections between skin folds
  • Cancer risk - breast, uterine, prostate, renal, colon, pancreatic, gastric, gallbladder, and endometrium
  • Decreased life expectancy - morbidly obese patients live 10-15 years less than normal weight people

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Medical information made available on is not intended to be used as a substitute for professional medical advice, diagnosis, or treatment. You should not rely entirely on this information for your health care needs. Ask your own doctor or health care provider any specific medical questions that you have. Further, is not a tool to be used in the case of an emergency. If an emergency arises, you should seek appropriate emergency medical services.

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