Are You Obese?

The Doctor's Guide to Weight Loss Surgery : How to Make the Decision That Could Save Your Life
by Louis J. Flancbaum, M.D.

(Page 2 of 2)

"The first time I saw the word obese used to describe me was when I sneaked a look at my medical chart when my doctor walked out of the room. I was shocked. I knew I was fat-but it was hard to accept the fact that I was that far gone."

Maggie L., 54, 384 lbs. pre-op; 265 lbs. 3 years post-op

"I never saw the term morbidly obese until I read it in a magazine. It didn't take me long to understand what it meant. If I didn't begin to take care of my health-I was not going to live to a ripe old age."

Karen K., 38, 288 lbs. pre-op; 179 lbs. 1 year post-op

The medical, psychological, social, and economic consequences of obesity are directly related to body size. The greater the degree of obesity, the greater the health risk. In order to more accurately predict the increased health risk associated with obesity, it is necessary to accurately describe the degree of obesity.

Body Mass Index, Or Bmi

Obesity can be defined in several ways. In the past, people referred to height-weight tables (such as those published by the Metropolitan Life Insurance Company) to determine if their weight was appropriate for their height. The weights were often corrected for "frame size" (small, medium, large). In recent years, height-weight tables have fallen out of favor within the medical and scientific communities and have been replaced by a method that more accurately accounts for the relative contributions of height and weight-called the Body Mass Index, or BMI. (BMI is generally expressed as kg/m2, but for the sake of simplicity we will omit the kg/m2 notation in the remainder of the book.)

To calculate your BMI:

Multiply your weight in pounds by 705.

Divide that number by your height in inches.

Divide that number by your height in inches again.

You can also calculate your BMI by using the accompanying Table 2-1.

Ideal And Excess Body Weight

Although BMI is the preferred method for describing one's health risk as it relates to weight, the concepts of Ideal (or Desirable) Body Weight (IBW) and Excess Body Weight (EBW) are simple ones. The notion of an IBW, which is the ideal amount that a person should weigh, arose from the use of height-weight tables. Several formulas to estimate IBW exist, but the simplest is:

IBW (Women) = 100 lbs. for the first 5 ft. of height, + or

- 5 lbs. for each inch above or below. (For example, a woman 5 ft. 2 in. tall has an IBW = 110 lbs.)

IBW (Men) = 106 lbs. for the first 5 ft. of height, + or - 6 lbs. for each inch above or below. (For example, a man 5 ft. 2 in. tall has an IBW = 118 lbs.)

EBW, which is the amount that one is overweight, is calculated as follows:

EBW = Actual body weight (ABW) minus IBW

In addition to estimating how much a person "should weigh" and how much he or she is overweight, IBW and EBW are most useful in estimating how much weight an individual can reasonably expect to lose following WLS. You can reasonably expect to lose at least 50 percent of your EBW following WLS.

Assessing The Relationship Between Weight And Health Risk

A normal BMI is between 19 and 25, and beyond this level, health risks increase steadily. In 1998, the World Health Organization, in its report Obesity: Preventing and Managing the Global Epidemic, proposed a new classification for health risk related to BMI. Individuals with BMIs between 20 and 25 are considered normal. Those with BMIs between 25 and 30 are classified as overweight, with only a mild to moderate increase in health risk. The risk increases as the BMI rises above 30 (obese), 35 (severe obesity), and 40 (morbid or clinically severe obesity). Individuals with a BMI greater than 50 are often referred to as super obese and carry the greatest threat to health. There is also a health risk associated with being too thin, with a BMI less than 19. (See Table 2-2.)

People with morbid or clinically severe obesity are at greatest risk for the various associated health problems. In the past, these labels were used when someone was 100 pounds above ideal body weight or twice his or her ideal weight. With more widespread use of BMI to describe health risk, this corresponds to a BMI greater than 40 or greater than 35 in the presence of life-threatening complications. In general, co-morbid medical conditions are most common in patients with severe and clinically severe/morbid obesity.

When describing the effects of obesity treatment, it is necessary to evaluate weight loss and its impact on associated health risks. A better and more scientifically accurate approach would probably be to estimate how many BMI units one would have to lose in order to lower overall health risk and reach a "healthier weight." However, it is much more understandable to express weight loss in pounds ("I lost 100 pounds") than in BMI units ("My BMI went from 50 to 27").

Copyright © 2003 by Louis Flancbaum, M.D.

About the Author

Louis J. Flancbaum, M.D., Chief, Division of Bariatric Surgery at St. Luke's-Roosevelt Hospital Center in New York City, and Associate Professor of Clinical Surgery at the College of Physicians and Surgeons of Columbia University, is a nationally-recognized authority on the surgical treatment of obesity. Dr. Flancbaum has performed nearly 1,000 bariatric surgical procedures. He has operated successfully on patients ranging in age from 15 to 70, weighing as much as 770 pounds. He has made many international presentations and published more than 100 articles in medical journals, and is board certified in General Surgery, Surgical Critical Care and Nutrition Support. His study, with Dr. Patricia Choban, of patient satisfaction after weight loss surgery, received national attention.