1. Body mass index (BMI)
    • Measure of weight in relation to height
    • sometimes used as a diagnostic tool, but it should not
    • BMI = weight/2(height) x 703
  2. BMI for different sizes
    • Healthy adult 18.5-24.9
    • Overweight 25-29.9
    • Obesity >30
    • Morbidly obese >40
  3. Other ways to measure obesity
    • BMI
    • weight circumference
    • skinfold thickness
    • hydrodensitometry
    • bioimpedence
  4. Childhood obesity facts
    • prevalence of pediatric overweight and obesity in the US has more than quadrupled over the past 40 years
    • 25% children overweight
    • 75% of parents of obese children think their child's weight is normal
    • 70% of obese children grow up to be obese adults
  5. Childhood mortality
    • lowers child's life expectancy by 8 - 20 years
    • very high adolescent BMI associated with 30-40% higher adult mortality
    • obese teenagers died on average at the age of 46
  6. Prevalence of obesity among US adolescents
    • more prevalent among native american boys
    • most groups fall b/w 10-20% range
    • US falls into 20-25% range
  7. Contributing factors
    • evolution
    • genetics
    • environmental
  8. Evolution
    humans are predisposed to prefer sweet and fatty tastes and reject sour and bitter tastes
  9. Genetic factors
    • genetic studies have shown lifetime obesity risk to be due to genetics
    • twin studies show that genetics account for as much as 50-90%
    • wide array of rare mutations and chromosomal abnormalities are now known to cause severe, early onset obesity
  10. monogenic
    • single gene mutation
    • many in the leptin/melanocortin pathway
    • very rare
  11. syndromic
    genetic defects causing obesity, mental retardation, dysmorphic features, and organ specific developmental abnormalities
  12. polygenic
    • individual's genetic makeup is susceptible to an environment that promotes energy consumption over energy expenditure
    • most common
  13. Environmental factors
    • movement, activity, exercise
    • dietary
    • school
    • fat, carbs
    • health
    • SES
    • dieting
  14. fat increases energy intake
    • passive over-consumption: signals may not reflect actual nutrient content
    • minimal appetite suppressant effect
    • high energy density
    • high palatability and hedonic value
    • aggressive marketing by the food industry
    • culturally acceptable
  15. Exercise/activity
    • 25% decrease in play and 50% decrease in outdoor activities during school
    • time spend doing hw and sitting in cars -> increased
    • children in unsafe neighborhoods watch more TV than kids in safe neigh
    • time spent watching TV has increased by 40 min per day
  16. Less labor in jobs
    • shift toward capital intensive and knowledge based employment
    • increased mechanization or previously labor intensive jobs
  17. Travel
    • less energy expended getting to and from work
    • increased use of transportation
    • suburbs
    • more technology at home
    • less energy expended to get food
  18. SES
    low SES associated with higher obesity
  19. health factors
    • endocrine disorders -> hypothyroidism, Cushing's disease
    • hypothalamic obesity -> trauma, tumors
    • genetic syndromes -> prader-willi syndrome
  20. sleep problems
    • sleep affects weight
    • ghrelin: hormone that tells body it is hungry -> produced more when can't sleep
    • kids who received less than 9 hours of sleep a night more likely to be overweight
    • once overweight, they can develop sleep disorders making it hard for them to sleep
  21. medical complications
    • left-side of heart become enlarged
    • high cholesterol
    • high blood pressure
    • thickening of arteries
    • heart disease, diabetes, stroke
    • higher risk for cancers
    • strained or broken joints
  22. metabolic syndrome
    • 3 of these symptoms means they are on their way to heart disease
    • high degree of belly fat
    • high blood pressure
    • glucose intolerance
    • high triglycerides
    • low good cholesterol (HDL)
  23. Type II diabetes
    • increased body fat and high dietary sugar -> increased insulin release -> insulin receptors become insensitive
    • fat cells become stressed
    • obesity and diabetes -> increase
  24. discrimination
    • characteristics
    • children's attitudes related to body weight
    • obese people report discrimination in jobs, by doctors...
    • discrimination is overt and hostile
    • discrimination can have a negative impact on health
  25. psychological health
    • psychopathology
    • only in BED -> overtime they gain weight
    • subthreshold depression, anxiety
    • self-esteem
    • lower in obese people
    • fewer social interactions by obese people
  26. Access to health care
    • embarrassment and discrimination
    • criticism and cruel remarks by physicians
    • blaming any health problem on weight
    • economic hardships
    • obesity more prevalent in lower SES in the US
    • overweight during adolescence has been associated with decreased SES in adulthood
  27. health risks
    • obesity does not cause the health risks
    • interacting factors, including obesity, lead to health risks
  28. prevention
    • research and prevention resources are more focused on obesity prevention than they ever were on eating disorders
    • obesity prevention could trigger an eating disorder b/c it is so weight focused
    • collaboration: obesity and eating disorder prevention
Card Set
Lecture 8