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  Obesity
 
Author: Kerry Stewart, Ed.D. Last modified: December 11, 2001
DIAGNOSTIC CRITERIA

  EPIDEMIOLOGY

  • About 97 million adults in the United States are overweight or obese.
  • The number of overweight and obese persons has risen since 1960; in the last decade the percentage of people in these categories has increased to 54.9 percent of adults age 20 years or older.
  • Overweight and obesity are highly prevalent in some minority groups, and among individuals with lower incomes and less education.
  • These conditions increase the risk of hypertension, dyslipidemia, type 2 diabetes, coronary disease, stroke, gallbladder disease, osteoarthritis, sleep apnea and respiratory problems, and several type
  • Higher body weight is also associated with an increased risk of death from any cause.
  • Besides total body fat, the presence of excess fat in the abdomen relative to total body fat is also an independent predictor of risk factors and morbidity.

  RISK FACTORS

  • Obesity is a complex multi-cause chronic disease resulting an interaction of genotype and the environment.
  • While the specific causes may differ among individuals, the condition generally involves a combination of social, behavioral, cultural, physiological, metabolic and genetic factors.

  SIGNS AND SYMPTOMS

  • The need for weight loss and prevention of weight gain is based on BMI and waist circumference.
  • Complications of overweight and obesity are hypertension, type 2 diabetes, hyperlipidemia, cardiovascular disease, osteoarthritis of the lower extremities, gallbladder disease, gout, and cancers.

  DIFFERENTIAL DIAGNOSIS

  • While several advanced technological methods to assess body composition exist, the body mass index, or BMI, which describes relative weight for height, is significantly correlated with total body fat
  • The BMI is a simple measure that for assessing overweight and obesity and for monitoring changes in body weight.
  • Measurements of body weight alone can also be used to determine efficacy of weight loss therapy.
  • BMI is calculated as weight (kg)/height squared (m2). To estimate BMI using pounds and inches, use: [weight (pounds)/height (inches)2] x 703.
  • Individuals with a BMI of 25 to 29.9 are considered overweight.
  • Individuals with a BMI of 30 or greater are considered obese.
  • Weight classifications by BMI (kg/m^2) are: Underweight, <18.5; Normal, 18.5 to 24.5; Overweight, 25 to 29.9; Obesity I, 30 to 34.9; Obesity II, 35 to 39.9; Extreme Obesity, >40.
  • For abdominal waist circumference is a useful measure before and during weight loss treatment.
  • Cutoffs for developing obesity-associated risk factors in adults with a BMI of 25 to 34.9. Men > 102 cm (> 40 in); Women > 88 cm (> 35 in).
  • These cut points lose their incremental predictive power in individuals with a BMI > 35 because they will exceed the waist circumference cut points noted.
 
TREATMENT
GOALS ARE TO REDUCE BODY WEIGHT AND PREVENT WEIGHT GAIN.
THE INITIAL GOAL OF WEIGHT LOSS TREATMENT IS TO REDUCE WEIGHT BY ABOUT 10 PERCENT IN 6 MONTHS.
A DIETARY CALORIC REDUCTION OF 300 TO 500 KCAL/DAY WILL RESULT IN A WEIGHT LOSS OF 1/2 TO 1 LB/WEEK
SEVERE OBESITY REQUIRES A CALORIC DEFICITS OF 500 TO 1,000 KCAL/DAY.
THE LOW-CALORIE DIET SHOULD BE CONSISTENT WITH NCEP GUIDELINES FOR DIETARY FAT REDUCTION.
BESIDES DECREASING SATURATED FAT IN THE DIET, TOTAL FATS SHOULD BE 30 PERCENT OR LESS OF TOTAL CALOR
MOST WEIGHT LOSS OCCURS THROUGH CALORIE REDUCTION, INCREASED PHYSICAL ACTIVITY IS A USEFUL ADJUNCT T
ALL INDIVIDUALS SHOULD ACCUMULATE AT LEAST 30 MINUTES OF EXERCISE, ON MOST, IF NOT EVERY DAY.
30 MINUTES OF EXERCISE WILL EXPEND 100 TO 200 ADDITIONAL CALORIES PER DAY.
BEHAVIOR THERAPY IS ALSO IMPORTANT FOR WEIGHT LOSS AND MAINTENANCE.
WEIGHT LOSS SURGERY IS AN OPTION IN SOME PATIENTS WITH SEVERE OBESITY
THE USE OF WEIGHT LOSS MEDICATIONS SHOULD CONSIDER THE POTENTIAL RISKS AND BENEFITS.
 
IMPORTANT POINTS/RECOMMENDATIONS
  • Initial goal of weight loss is 10% of body weight over 6 months. Weight loss goal is 1-2 lbs per week. This can often be achieved with a calorie deficit of 500-1000 per day.
  • Low calorie diets, with an emphasis on reducing fat, are recommended. Weight loss is recommended for reducing CV disease risks, particularly in individuals with hypertension, diabetes, and hyperlipid
  • BMI and waist circumference are used to categorize overweight and obesity, and for tracking responses to weight loss programs.
  • Physical activity is a useful adjunct to diet.
  • Weight loss drugs are available for use in selected individuals in conjunction with diet and physical activity interventions.
  • Because of increased weight gain after loss, individuals need to continue to follow diet, physical activity, and behavioral interventions, and if needed, drugs.
 
REFERENCES
  1. National Institutes of Health, National Heart, Lung, and Blood Institute. ;  The Practical Guide. Identification, Evaluation, and Treatment of Overweight and Obesity in Adults. ;  National Institutes of Health, National Heart, Lung, and Blood Institute. NIH Publication Number 00-4084. October 2000.

  2. Centers for Disease Control and Prevention. ;  Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion. Surgeon General’s report on physical activity and health ;  Atlanta, GA: CDC; 1996.

  3. National Institutes of Health ;  NIH Consensus Conference. Physical activity and cardiovascular health. ;  JAMA. 1996;276:241-246.

  4. National Institutes of Health ;  Methods for voluntary weight loss and control. NIH Technology Assessment Conference Panel. ;  Ann Intern Med.1992; 116:942-949.

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