Obesity and associated health risks

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.

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 700, then dividing the result by your height in inches and dividing that result by your height in inches. For an even easier way to calculate your BMI 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.

How to measure your obesity?

Measuring Obesity

A number of tools are available to measure obesity. Most are based on height and weight ratios, body size and shape, and percent body fat. All have benefits as well as limitations. (A doctor or other health professional can perform these tests most accurately.)

Body Mass Index (BMI)Determines underweight (<18.5), normal weight (18.5-24.9), overweight (25.0-29.9), and obese (30.0 – 39.9) based on a person's height and weight. A result greater than 40 is considered morbidly obese, which can be a potentially deadly situation.

BMI is the most popular method of determining weight status by health care professionals. The BMI is limited however, because it does not account for weight from muscle versus that from fat. Below is a BMI table showing height and weight and the associated BMI units for adults.
Waist Circumference This measurement in combination with BMI has shown to be the best predictor of obesity and associated health risks.

The size of a person's waist can help predict risk of certain diseases. A waist size greater than 40 inches for men and 35 inches for women increases risk for most weight-related illnesses. Waist circumference is also used to determine a person's body shape. Body shape is based on how a person carries extra weight, and is used as an important predictor of health risk.
“Apple” versus “Pear” Shape People who carry extra weight around their bellies are considered “apple” shaped. Those who carry it around their hips and buttocks are “pear” shaped. People with “apple” shapes are at risk for developing obesity-related health problems. The pictures below illustrate the “apple” and “pear” shapes”.

Waist- to- Hip Ratio (WHR)WHR is the ratio of a person's waist circumference to their hip circumference, and is also used to determine risk for weight-related illnesses. This is calculated by dividing the person's waist measurement by their hip measurement. A WHR greater than 1.0 in men or greater than 0.8 in women is considered obese.
How to measure waist circumference-Using a tape measure, comfortably measure your waist right below the rib cage and above the belly button. How to measure hip circumference? Using a tape measure, comfortably measure your hips around the largest portion of the buttocks.

The BMI, Apple vs. Pear, and WHR are useful tools for giving a general idea of how weight might affect your health. They do not tell you how weight is affecting your health imparticular. It is always a good idea talk with your doctor about your weight and weight management strategies when you have concerns or questions.