How Are Overweight and Obesity Defined?

The body mass index (BMI) is the most popular tool for defining what is healthy weight, overweight and obesity today. The BMI is calculated by multiplying weight in pounds by 703 and then dividing by the height in inches squared. This approximates BMI in kg/m2. The 1998 Clinical Guidelines on the Identification, Evaluation and Treatment of Overweight and Obesity in Adults, developed by the National Heart, Lung and Blood Institute, recommend the following classifications for BMI:

• Underweight: BMI less than 18.5
• Normal weight: BMI 18.5 to 24.9
• Overweight: BMI 25 to 29.9
• Obesity (Class 1): BMI 30 to 34.9
• Obesity (Class 2): BMI 35 to 39.9
• Extreme Obesity (Class 3): BMI greater than 40

BMI does not actually measure body fat, but generally correlates well with the degree of obesity. For example, a person who is 5 feet, 7 inches tall and weighs 150 pounds would have a BMI of 23, well out of the range of obesity. A person of the same height and weighing 200 pounds would have a BMI of 31 and would be considered obese. BMI charts are widely available.

Often, a 10 to 15% reduction in an obese person's body weight can bring about a significant reduction in the person's health risk from obesity. This "healthy" weight loss does not always equate with a person's "cosmetic" weight loss goals.

How are Obesity and Health Risk Measured?

Currently, several different measures are used to evaluate a patient's weight status and potential health risk. However, a complete evaluation includes assessments of a person's age, height and weight, fat composition and distribution, and the presence or absence of other health problems and risk factors.

Height-weight tables indicating "ideal" weight have been in use since 1959 but have their shortcomings. A newer measure of obesity that is gaining in popularity among researchers and clinicians is the body mass index (BMI). BMI is the body weight in kilograms divided by the square of the height in meters ([weight in kg] ÷ [height in meters]2). BMI does not actually measure body fat, but generally correlates well with the degree of obesity. The categories of obesity developed by the World Health Organization are:

• BMI 25 to 29.9 : Grade 1 obesity (moderate overweight)
• BMI 30 to 39.9 : Grade 2 obesity (severe overweight)
• BMI > 40 : Grade 3 obesity (massive/morbid obesity)

Using a BMI table, a person 5'6" tall weighing 140 pounds would have a BMI of 23, well out of the range of risk. That same 5'6" person weighing 190 pounds would have a BMI of 31, in the range of Grade 2 obesity.

A BMI of 27 or higher is associated with increased morbidity and mortality; this is generally considered the point at which some form of treatment for obesity is required. A BMI between 25 and 27 is considered a warning sign and may warrant intervention, especially in the presence of additional risk factors. At the Nu-Living Weight Management we use the newest outpatient technology to accurately trend your body composition, which establishes your Body Mass Index (BMI).

BMI is defined as body weight (in kg) divided by height (in m2 ). You can easily calculate your BMI by multiplying your weight in pounds by 703, then dividing the result by your height in inches and dividing that result by your height in inches. Your BMI in a snap: use our Quick BMI Calculator.

In recent years, researchers and clinicians have shifted focus from "ideal" body weights as reflected in the height-weight tables, to helping patients achieve and maintain "healthy" or "healthier" body weights. Studies have shown that losing even modest amounts of weight - just 5 to 10 percent of initial body weight - and maintaining the loss improves health and well-being and decreases the risk for a variety of obesity-related health complications.

According to the ASBP, a comprehensive medical weight loss program should include the following:

1. An initial patient work-up to include medical history, physical examination, appropriate laboratory studies and an electrocardiogram if there is past or present evidence of cardiac disease or if the patient has coronary risk factors.
2. Appropriate counseling on:
   
   • Diet and nutrition, including reduced calorie diets and very low calories diets (VLCD) and dietary supplements when needed.
   • Exercise, tailored to the capabilities and limitations of the overweight patient to ensure safe and effective exercise.
   • Behavior modification (lifestyle changes), to include discussions of proper eating habits, dealing with stress-related eating, family meal planning changes, healthful snacking, etc.
   • Prescription appetite suppressants, if indicated, as an adjunct to a comprehensive medical weight loss program, and other medications.
3. If the use of appetite suppressants or other medications is indicated, the patient should be informed about the potential risks of such medication and the physician and patient should weigh the risks of the medication against the benefits, i.e., do the small risks of the medications outweigh the health risk of the patient remaining obese. (The use of appetite suppressants is not indicated for patients with only a small amount of weight to lose.) Often, the loss of only 5 to 10 percent of a patient?s initial weight can lead to significant improvements in health status.
4. Adequate periodic follow-up and counseling, to include a program to help the patient maintain the weight loss that has been achieved. At Nu-Living Weight Management we provide exactly this kind of counseling. Contact us for an appointment.