What Is Obesity? Select below for more information
Some facts about the prevalence of obesity Measuring Obesity and Health Risk Determining Patient’s BMI-Related Health Risk Weight Reduction Treatment Options Obesity used to be understood in fairly simple terms, excess body weight resulting from eating too much and exercising too little, due in large part to a lack of willpower or self-restraint. Fortunately for the millions of American adults who are overweight, obesity is now regarded as a chronic medical disease with serious health implications caused by a complex set of factors.
Recognized since 1985 as a chronic disease, obesity is the second leading cause of preventable death, exceeded only by cigarette smoking. Obesity has been established as a major risk factor for hypertension, cardiovascular disease, diabetes mellitus and some cancers in both men and women. Obesity affects 58 million people across the nation and its prevalence is increasing. Approximately one-third of adults are estimated to be obese.
Obesity results from a complex interaction of genetic, behavioral and environmental factors causing an imbalance between energy intake and energy expenditure. According to the National Institutes of Health, an increase in body weight of 20 percent or more above desirable weight is the point at which excess weight becomes an established health hazard. Lower levels of excess weight can also constitute a health risk, particularly in the presence of other disorders like diabetes, hypertension and heart disease.
Some facts about the prevalence of obesity: * The U.S. Bureau of the Census estimates that approximately 58 million American adults (26 million men and 32 million women) are obese.
* The prevalence of obesity increased by 9 percent among women and men ages 20 to 74 between 1960 and 1991.
* Approximately one third (33.4 percent) of adults are estimated to be obese.
* Adult men and women are nearly 8 pounds heavier than they were 15 years ago. Mean body mass index (BMI), a standard measure of obesity, has increased from 25.3 to 26.3 kg/m2.
* At any given time 33 to 40 percent of women and 20 to 24 percent of men are trying to lose weight.
* Maintaining weight loss over the long term is exceedingly difficult. Most people regain as much as two-thirds of weight lost within one year and regain all of it within five years.
Measuring Obesity and Health Risk 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.
Body Mass Index (BMI) kg/m2
Height (ft, in)
Weight (lb) 5'0" 5'3" 5'6" 5'9" 6'0" 6'3" 140 27 25 23 21 19 18 150 29 27 24 22 20 19 160 31 28 26 24 22 20 170 33 30 28 25 23 21 180 35 32 29 27 25 23 190 37 34 31 28 26 24 200 39 36 32 30 27 25 210 41 37 34 31 29 26 220 43 39 36 33 30 28 230 45 41 37 34 31 29 240 47 43 39 36 33 30 250 49 44 40 37 34 31
No Obesity BMI >= 27 kg/m2
(approximately 20% above ideal weight)BMI >= 30 kg/m2
(approximately 30% above ideal weight)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 Click Here
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.
Determining Patient’s BMI-Related Health Risk
BMI Category Health Risk With Comorbidities** < 25 Minimal Low 25 - <27 Low Moderate 27 - <30 Moderate High 30 - <35 High Very High 35 - <40 Very High Extremely High >40 Extremely High Extremely High **Hypertension, cardiovascular disease, dyslipidemia, Type II diabetes, sleep apnea, osteoarthritis, infertility, other conditions.
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Weight Reduction Treatment Options
Health Risk Treatment Option(s) Available Minimal and Low Healthful eating and/or moderate deficit diet
Increased physical activity
Lifestyle Change strategiesModerate All of the above plus low calorie diet High and Very High All of the above plus pharmacotherapy and very low calorie diet Extremely High All of the above plus surgical intervention *From Guidelines for Treatment of Adult Obesity, Shape Up America and the American Obesity Association, 1996.
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