- 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
- Stierman (2021) Natl Health Stat Report 158 [PubMed]
- 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
- See Obesity Evaluation
- See Obesity Measurement
- See Obesity Risk
- Screen at least once yearly for Obesity in adults
-
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
- Complications
-
Conditions for which Obesity Contributes
- Research
-
Obesity Gene (ob)
- Ob expression
- Feeding turns on rat adipocytes via Insulin
- Inhibit Neuropeptide Y synthesis at appetite center
- Neuropeptide Y
- Decreases thermogenesis
- Increases Insulin and appetite
- Ob gene function: Produces Leptin (Protein)
- Leptin uppresses appetite in rats
- Leptin increases thermogenesis in rats
- Leptin decreases Insulin levels in rats
- References
- Saladin (1995) Nature 377:527-9 [PubMed]
- Stephens (1995) Nature 377:530-2 [PubMed]
- Pelleymounter (1995) Science, 269(5223):540-3 [PubMed]
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