Obesity

Obesity

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Obesity, Overweight

  • See Also
  1. Obesity in Children
  2. Obesity Evaluation
  3. Obesity Measurement (or Obesity Screening)
  4. Obesity Risk (or Obesity Comorbid Conditions)
  5. Obesity Management
  6. Obesity Medication
  7. Dietary Supplements in Obesity
  8. Exercise in Obesity
  9. Obesity Resources
  • Epidemiology
  1. Patients gain a mean 1 pound (2.2 kg) per year after age 25
  2. Prevalence: 41.9% US adults age 20 to 74 are obese (CDC 2017-2020)
    1. Obesity in 100 Million U.S. adults (22 million with severe Obesity, BMI>40)
    2. Adult obesity Prevalence has increased in U.S. from 30.5% in 1999-2000
  3. References
    1. Stierman (2021) Natl Health Stat Report 158 [PubMed]
  • Pathophysiology
  • Fat expands in 2 ways
  1. Fat Cell Number
    1. Fat cell number does not decrease with weight loss
    2. Increases 5 fold until age 22 years
    3. Increase continues with nutritional excess
    4. Non-obese person has 25-30 billion fat cells
    5. Obese person has 260 billion cells
  2. Fat Cell Size
    1. Fat cell size reduces with weight loss
    2. Adults fill existing fat cells when they over eat
  • Evaluation
  1. See Obesity Evaluation
  2. See Obesity Measurement
  3. See Obesity Risk
  4. Screen at least once yearly for Obesity in adults
  • Diagnosis
  • Obesity
  1. Body Mass Index (BMI in kg/m2) Grading: Non-Asian Descent
    1. BMI 25 to 30: Overweight
    2. BMI 30 to 35: Class 1 Obesity
    3. BMI 35 to 40: Class 2 Obesity
    4. BMI >40: Class 3 Obesity (Severe Obesity)
  2. Body Mass Index (BMI in kg/m2) Grading: Asian Descent
    1. BMI 23 to 27.5: Overweight
    2. BMI 27.5 to 32.5: Class 1 Obesity
    3. BMI 32.5 to 37.5: Class 2 Obesity
    4. BMI >37.5: Class 3 Obesity (Severe Obesity)
  3. Waist Circumference Overweight Criteria
    1. Female >=35 inches (>=31 in asian descent)
    2. Male >=40 inches (>=35 in asian descent)
  4. Body Fat Percent Overweight Criteria
    1. Female >= 32%
    2. Male >= 25%
  5. Prior Obesity definitions
    1. Men: 20% over estimated Ideal Weight
    2. Women: 30% over estimated Ideal Weight
  • Management
  1. See Obesity Management
  2. See Obesity Medications
  3. See Obesity Resources
  • Complications
  • Conditions for which Obesity Contributes
  1. Coronary Artery Disease
  2. Cerebrovascular Accident
  3. Gallbladder Disease
  4. Hypertension
  5. Hyperlipidemia
  6. Malignancy (Endometrial Cancer, Breast Cancer, Prostate Cancer, Colon Cancer)
  7. Obstructive Sleep Apnea
  8. Osteoarthritis
  9. Type 2 Diabetes Mellitus
  • Research
  • Obesity Gene (ob)
  1. Ob expression
    1. Feeding turns on rat adipocytes via Insulin
    2. Inhibit Neuropeptide Y synthesis at appetite center
    3. Neuropeptide Y
      1. Decreases thermogenesis
      2. Increases Insulin and appetite
  2. Ob gene function: Produces Leptin (Protein)
    1. Leptin uppresses appetite in rats
    2. Leptin increases thermogenesis in rats
    3. Leptin decreases Insulin levels in rats
  3. References
    1. Saladin (1995) Nature 377:527-9 [PubMed]
    2. Stephens (1995) Nature 377:530-2 [PubMed]
    3. Pelleymounter (1995) Science, 269(5223):540-3 [PubMed]
  • References
  1. Keating (2024) Am Fam Physician 110(2): 145-56 [PubMed]