Obesity

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Obesity

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

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