II. Epidemiology
- Patients gain a mean 1 pound (2.2 kg) per year after age 25
-
Prevalence: 41.9% US adults age 20 to 74 are obese (CDC 2017-2020)
- Obesity in 100 Million U.S. adults (22 million with severe Obesity, BMI>40)
- Adult obesity Prevalence has increased in U.S. from 30.5% in 1999-2000
- References
III. Pathophysiology: Fat expands in 2 ways
- Fat Cell Number
- Fat cell number does not decrease with weight loss
- Increases 5 fold until age 22 years
- Increase continues with nutritional excess
- Non-obese person has 25-30 billion fat cells
- Obese person has 260 billion cells
- Fat Cell Size
- Fat cell size reduces with weight loss
- Adults fill existing fat cells when they over eat
IV. Evaluation
- See Obesity Evaluation
- See Obesity Measurement
- See Obesity Risk
- Screen at least once yearly for Obesity in adults
V. Diagnosis: Obesity
-
Body Mass Index (BMI in kg/m2) Grading: Non-Asian Descent
- BMI 25 to 30: Overweight
- BMI 30 to 35: Class 1 Obesity
- BMI 35 to 40: Class 2 Obesity
- BMI >40: Class 3 Obesity (Severe Obesity)
-
Body Mass Index (BMI in kg/m2) Grading: Asian Descent
- BMI 23 to 27.5: Overweight
- BMI 27.5 to 32.5: Class 1 Obesity
- BMI 32.5 to 37.5: Class 2 Obesity
- BMI >37.5: Class 3 Obesity (Severe Obesity)
-
Waist Circumference Overweight Criteria
- Female >=35 inches (>=31 in asian descent)
- Male >=40 inches (>=35 in asian descent)
- Body Fat Percent Overweight Criteria
- Female >= 32%
- Male >= 25%
- Prior Obesity definitions
- Men: 20% over estimated Ideal Weight
- Women: 30% over estimated Ideal Weight
VI. Management
- See Obesity Management
- See Obesity Medications
- See Obesity Resources