Obesity Body Composition

1. Obesity & Body Composition

2. Obesity

3. Obesity What diseases are associated with obesity? Heart disease Hypertension Diabetes Renal disease Pulmonary disease Osteoarthritis Cancers

4. Obesity $58 million Creeping obesity lower metabolic rate sedentary lifestyle Over-eating Not a requirement of aging A long-term process Is not solely related to overeating

5. Obesity How does it develop? Obesity cycle

6. Obesity Genetics Number of calories consumed Dietary recall Isotope studies Types of foods eaten Fat is more easily stored than carbohydrates or proteins High fat and high glycemic index foods Daily activity Which comes first inactivity or obesity? Increases resting metabolic rate (due to increase in fat free mass) Increases caloric expenditure(during exercise

7. Obesity - Genetics 25-40% of the cause of obesity Internal fat more so than subcutaneous fat Ob gene Creates leptin (Greek for thin) that is responsible for satiety Leptin inhibits neuropeptide Y (NPY) which stimulates food intake

8. Obesity - Genetics Genes may decrease number of leptin receptors in hypothalmus Differences in resting metabolic rate Predisposition of sweet, high-fat food Impaired hormonal functions Insulin, cortisol, hGH Greater number of fat cells

11. Obesity – Calories Consumed 3500 calories equal a pound of fat Over eating can make is easier for the body to store fat and harder for it to remove fat

12. Insulin

13. Fat Transport

17. Lipoprotein Lipase Adipose (Capillary) LPL Breaks down Chylomicrons, VLDL and LDL Their triglycerides are stored in fat cells Muscle LPL (or type L-Hormone sensitive lipase) Breaks down fats for metabolism inside muscle cells

18. Syndrome X Consider a person who over eats (high fat, high sugar) and is inactivity What affect would this lifestyle have on insulin? 1. Insulin resistance and Hyperglycemia How would this affect body composition? Obesity

19. Syndrome X Insulin resistance and Hyperglycemia Decrease in muscle LPL (type L-HSL) Decrease in fat metabolism Increase in adipose LPL in adipose cells Increase in fat storage

20. Syndrome X Other conditions of syndrome. 1. Insulin resistance and Hyperglycemia 2. Hypertension 3. Hyperlipidemia

21. Syndrome X Hypertension Hyperinsulinemia Sodium retention Increased arterial resistance Increase adipose tissue with relatively fewer capillaries

22. Syndrome X Hyperlipidemia (high blood fats) With obesity... High cholesterol (25%) High triglycerides (75%) Low HDL Decease LPL in liver Less TG removal Increase LDL production Increase HDL removal

23. Syndrome X How does exercise help? Exercise increases GLUT-4 (reduces insulin resistance) Increase oxidative enzymes (increase fat metabolism) Increase muscle blood flow Reduces abdominal fat

24. Obesity – Type of Food Glycemic Index Less sugars and straches More fruits, vegetables, and whole grains Thermic effect of food:Highest for protein, carbohydrates and then fats Fats can only be stored as fat Carbohydrates and proteins have other options

25. Obesity - Environment

26. Obesity - Inactivity

27. Obesity Energy Imbalance

28. Energy Balance Energy (food) intake Energy expenditure

29. Energy Balance Unbalance... Eat less More active Both Diet 3% of calories to store fat 25% of calories to store carbohydrate Exercise

30. Total Energy Expenditure Resting Metabolic Rate Thermogenesis Thermic effect of food Thermogenic substances (catecholamines, drugs, etc) Facultative Thermogenesis (cold exposure) Psychological stress Physical Activity

32. Energy - Resting Metabolic Rate 70% of total energy expenditure (TEE) 10% difference among people RMR influenced by body size, age, sex, and Fat-free mass (FFM)

34. Energy - Resting Metabolic Rate RMR influenced by body size, age, sex, and Fat-free mass (FFM) RMR = 370 + (21.6 x fat-free mass in kg)

36. Energy - Thermic effect of food 5-10% of TEE Highest for protein, carbohydrates and then fats Less for obese Higher if exercise before (or after) eating

37. Energy - Facultative Thermogenesis Shivering Increase metabolic rate up to 5 times Brown adipose tissue (BAT) Higher metabolic rate than white fat

38. Energy - Food Intake Hypothalmus Hunger center Satiety center Gluostatic theory Lipostatic theory Leptin Released from adipose cells Decreases appetite Obese may have defective leptin receptors in brain

39. Energy - Food Intake Aminostatic theory Thermostatic theory Heat from digestion Other factors GI stretch receptors Nutrient level Hormone levels Psychological factors

40. Energy – Set Point Theory Hypothalmus controls body weight similar to how a thermostat controls temperature Increase body fat releases leptin Leptin inhibits neuropeptide Y (NPY) which stimulates food intake Fat levels decrease to normal or previous levels Decrease body fat inhibits leptin release NPY increase and stimulate hunger Fat levels increase to normal or previous levels

41. Energy Expenditure

42. Energy Expenditure

43. Energy – Weight Gain

44. Energy – Weight Gain Obesity: Larger cells or more cells? Obese individuals have 3x more and 40% larger adipose cells Weight loss mainly through decrease size However, fat cells can be added or deleted in adulthood

45. Energy – Weight Gain Hypertrophy Hyperplasia Average person 25-30 billion Obese person 260 billion Number of cells increase up to age 10 Further weight gain due to hypertrophy Hyperplasia occurs with extreme weight gain

46. Energy – Weight Gain Nutrition Rats and litter size Activity Active at young age The key is early prevention

47. Energy – Healthy Weight Gain Increase caloric intake by 200 to 1000 kcals per day Increase healthy carbohydrates If needed, increase protein intake but no more than 2.0 g/kg of body weight Proper training with adequate rest

48. Weight Loss

49. Weight Loss - Dehydration Sweating Lose up to 1.5 to 4.0 liters per hour Low carbohydrate diet 1 gram of glycogen is stored with 3 grams of water Deamination of protein results in water loss

50. Weight Loss - Medical Procedures Starvation diets Surgery Bypass Liposuction Drugs Appetite-suppressing drugs Thermogenic drugs (RMR) Fat blocking drugs

51. Weight Loss - Dieting Water loss due to glycogen depletion 1/3 to 2/3 weight loss regained within 5 years Setpoint Theory: metabolic rate Weight cycling and Lipoprotein Lipase (LPL)

52. Weight Loss - Caloric Restriction Most common method Carbohydrate restriction Dehydration Loss of LBM Limits exercise Weight loss in independent of dietary composition (i.e. the type of food)

53. Weight Loss - Semi-starvation Diets Theory: less caloric intake, suppress appetite, change eating behavior, Concerns: requires medical supervision.

54. Weight Loss - Ketogenic Diet Ketones are a by product of lipid metabolism Ketones can serve as fuel to CNS Theory is they suppress appetite Excess ketones (a form of energy) is lost in urine rather than stored in the body

55. Weight Loss - Ketogenic Diets High uric acid levels Electrolyte loss Arrhythmias Acidoisis Kidney damage Fatigue

56. Weight Loss – Low Carbohydrate Diets Theory: suppress appetite, elevated thermic effect of digestion, better insulin control Concerns: kidney and liver damage, dehydration, electrolytes, loss of lean tissues, adequate vitamins and minerals, low energy level

57. Bowman SA ; Spence JT Am Coll Nutr (Journal of the American College of Nutrition.) 2002 Jun; 21(3): 268-74