Reasons for the Epdemic

1. Obesity Reasons for the Epdemic

2. Definition: • Obesity is abnormal weight gain that causes detrimental health effects • Classified by a body mass index (BMI) greater than 30. • Characterized by excessive adipose tissue

3. Morbidity Rates • In 1991, only four states had obesity prevalence rates of 15-19 percent • In 2004, however: • 7 states reported rates of 15-19 percent • 33 states displayed rates of 20-24 percent • 9 states showed rates greater than 25 percent

4. Morbidity Rates

6. Health Problems • The main problem with obesity is its propensity to exacerbate or cause other health conditions. • Obesity greatly increases risk of a plethora of other disorders.

7. Weight Gain • Weight gain occurs when net energy intake exceeds net expenditures. • Energy expenditure includes the basal metabolic usage and the kcal needed to fuel all daily activities • Superfluous calories are stored in adipocytes as trigycerides

8. Societal Change • Since 1985, the dietary and exercise habits of the American population have changed substantially. • Super-size generation • Increasingly sedentary • Empty calories are more available

9. Societal Change

10. Leptin

11. Leptin • Discovered in the early 1990s • Main regulating hormone of energy balance • Also called the OB protein • Produced by adipocytes, and act on the hypothalamus • Decrease appetite, raise metabolic rate

12. Leptin

13. Leptin

14. Neuropeptide Y • Main neuropeptide in the CNS • Acts antagonistically to leptin • Increases appetite, lowers metabolism • Binds to the Y1 or Y5 receptor • Controlled at the transcription level by leptin

15. Neuropeptide Y

16. Leptin Resistance • A number of problems can occur with the neuroendocrine control mechanism • These conditions are the real cause of obesity, not overeating • Leptin resistance is the most common of these problems • OB-R loses sensitivity

17. Leptin Resistance • Diet-induced obesity • Highly palatable, empty calories • Prolonged exposure to the cafeteria diet is damaging • Mouse diet similar to new American diet

18. Conclusion • The change in the American diet has led to an increase in leptin resistance among the population • It is the inability of the body to maintain energy homeostasis using the leptin neuroendocrine system that has led to the drastic increase in obesity morbidity in the past two decades.

19. Questions?

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