Obesity is a topic covered in the 5-Minute Clinical Consult.

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  • Obesity is the state of excess adipose tissue. Weight status can be defined using the body mass index (BMI = body weight [kg]/[body height (m)]2) and classified as underweight, normal weight, overweight, or obese:
    • For adults, a BMI ≥30 kg/m2 is consistent with obesity.
  • Obesity is associated with negative health outcomes (1), and the highest risk for increased morbidity and mortality is found in the context of abdominal obesity.
  • System(s) affected: endocrine/metabolic, cardiac, respiratory, gastrointestinal, musculoskeletal, dermatologic, mental health
  • Synonym(s): overweight; adiposity

Geriatric Considerations
BMI associated with the lowest risk of mortality increases as age increases.


  • Predominant age: Incidence rises in the early 20s.
  • Predominant sex: female > male

  • Mean prevalence of obesity among adults is 35% in the United States (2).
  • Overweight: 40% of men and 25% of women
  • Obese: 20% of men and 25% of women
Pediatric Considerations
  • Pediatric obesity is categorized as ≥95th percentile, as established by CDC growth curves, by age and sex.
  • Obesity during adolescence and young adulthood is strongly associated with obesity in adulthood.
  • Risk factors include insufficient physical activity, consumption of sweetened beverages, and excess screen time.

Etiology and Pathophysiology

  • Obesity is caused by an imbalance among food intake, absorption, and energy expenditure.
  • Underlying organic causes may be psychiatric disturbances, hypothyroidism, hypothalamic disorders, insulinoma, and Cushing syndrome.
  • Medications can contribute to obesity, including corticosteroids, neuroleptics (particularly atypical antipsychotics), and antidepressants

  • Genetic syndromes such as Prader-Willi and Bardet-Biedl are responsible for a minor percentage of people with obesity.
  • Studies are insufficiently powered to isolate genes as predictors of obesity.

Risk Factors

  • Parental obesity
  • Sedentary lifestyle
  • Consumption of calorie-dense food
  • Low socioeconomic status
  • >2 hours per day of television viewing

General Prevention

  • Encourage at least 1 hour of daily exercise, limited television viewing, and moderation in portion size.
  • Avoid calorie-dense and nutrient-poor foods such as sweetened beverages and processed foods.

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