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Obesity Obesity Presentation Transcript

  • OBESITY Chapter 15
  • Americans are FAT!
    • Highest per capita consumption of fat in the world!
    • 50 million men / 60 million women plus 10 – 12 million teenagers are over weight (33% of Americans)!
    • Reduction of 600 kcals / day would put average over weight adult at desired weight in 68 – 101 days!
  • Obesity is a Business… and Business is GOOD!
    • 33-40% of American women and 20 – 24% of American men currently diet!
    • Diet spending exceeds $30 BILLION ANNUALLY!!!
    • Usually spent on product that don’t work.
  • “Creeping Obesity”
    • Greatest fat gain is from 25 – 44 years of age in most people.
    • Average man will gain .2 and .8 kg per year. This equates to an average of over a pound a year.
    • 14% of all women will gain over 30 lbs from age 25 to 34.
  • How fat is TOO fat?
    • Men:
      • (Young) Less than 20%
      • (Older) Less than 25%
    • Women
      • (Young) Less than than 30%
      • (Older) Less than 37%
  • What makes us fat?
      • BMR / Body temperature / Dietary Thermogenesis
      • Spontaneous activity / Cellular [ATP] ?
      • Lipoprotein Lipase Activity & other enzymes
      • Level of brown adipose tissue
      • Leptin ?
    • Lack of Activity
    • Overeating
  • Genetic Links
    • Twin studies show that individuals with identical genes are almost exclusively either both overweight or of normal weight.
    • Children with one or both parents who are obese have a 2X + risk of being an obese adult.
    • Study in Cambridge University has isolated at least two genes that when manipulated…control weight gain / loss (Leptin)
  • Leptin ?
    • Leptin: A hormone like protein produced in the fat cells of the body.
      • When leptin levels are high in the blood stream…appetite is suppressed. (Neg. Feedback loop)
      • It is believed that some people have genetic abnormality…produce less leptin.
      • Possibly reversed through gene therapy?
  • Physical Activity
    • Activity blunts the weight gain seen with aging.
    • Studies in active adults
      • No statistical relationship between caloric consumption and body fat percentage
      • Linear relationship between activity level and body fat%.
    • Reduced physical activity is the MAIN cause of adult obesity!
  • Health Risks of Obesity
    • Should be viewed as a disease!
    • Over 12 million people in US are clinically obese.
    • Obesity appears to be as powerful of a risk factor for CHD as smoking, elevated cholesterol, & hypertension!
    • Even being 2 – 5 kg overweight has health implications (National Institute Of Health)
  • Health Risks of Obesity
    • Increased risk of:
      • CHD , hypertension , stroke , diabetes , renal disease, gallbladder disease, pulmonary diseases, osteoporosis, gout, abnormal plasma lipids, impaired cardiac function (heart failure), etc. etc. etc………
  • Regional Fat Distribution
    • Android (apple): High abdominal fat content. Very metabolically active. High risk of heart and metabolic diseases. (LPL activity)
    • Gynoid (pear): Peripheral fatness. Less increase of CHD and metabolic disease.
    • Waist – Hip Ratio < 1.0 is desirable
  • Fat Cells
    • Adipose cells store majority of the body’s fat. Vary in size and number .
    • Increase in body fatness is due to:
      • Fat cell hypertrophy
      • Fat cell hyperplasia
  • Fat Cell Number
    • Number of fat cells appears to be biggest factor in determining risk for obesity.
      • Determined mostly in adolescent years
      • Average non-obese person: 25-30 bill.
      • Moderately obese: 60-100 bill.
      • Massively obese: 300 bill. +
  • Fat Cell Number
    • Fat cells development (significant  ):
      • Last trimester of pregnancy
      • First year of life
      • During adolescent “growth spurt”
    • Fat cell # is typically only increased with severe obesity.
  • Fat Cells and Weight Loss
    • Cells decrease in size, not number:
      • Studies have proven, fat cells ONLY decrease in size not number.
      • Individuals with higher number of cells, regained weight more readily.
      • Person’s with smaller, more numerous cells reported more “cravings” for food
        • Leptin?
  • Spot Reduction
    • Common misconception
    • Adipose tissue’s, lipid extraction pattern is GENETIC!!!
  • Fat Cells and Weight Gain
    • Typically only see an increase in size of existing cells in adults. (Hypertrophy)
    • If cells begin to reach their maximum size of 1.0 micrograms of lipid per cell then new cells may develop. (Hyperplasia)
  • Development of Adipose
    • As expected, studies have shown that nutritional and exercise interventions in the growing years, results in a LOWER FAT CELL NUMBER , and a subsequent decrease in relative RISK of obesity!!!