Unformatted text preview: Lecture 10 Lecture : Energy output 60-70 % of total energy used minimal amount of calories 60-70 the body uses to support itself and fasting state when rusty , for men -> BMR the 1Kcal/kg/hr , for women -> 0.9 kcal/kg/hr Major ways in which the body expands energy : 0. Basal Metabolic Rate (BMR) 0. Total Energy Expenditure 1. Physical Activity : increases energy expenditure beyond energy
needs by 25-40% 2. Thermic Effect of Food : 5-10% calories use 2. Basal Metabolic Rate Involuntary activities to sustain life including circulation, respiration, breathing, nerve activity, heart beating, temperature. Excludes digestion and voluntary activities. Largest component of daily energy expenditure Thyroxine is the hormone that control BMR Physical Activity Physical 3. Varies 4. Individual control Thermic Effect of Food 5. Energy used in digestion, absorption and transfer of nutrients 6. 150-300 kcals/day Thermogenesis - ability of human to regulate body temperature Factors that affect BMR Factors Height –The taller you are, the higher your BMR is Age - Lean body mass decreases w/age and your BMR decreases ( your BMR decreases 1~2 % every 10 years beginning at 30yr of age ) Growth(Pregnant wome,chidren) increases BMR Lean Tissue(muscle) increases BMR Fever increases BMR Stress increases BMR Fasting increases BMR Malnutrition decreases BMR Obesity Obesity 7. This is the 1st generation that will have worse health problems than
the generation before the 8. 35% adults overweight 9. 27% adults obese 10. 1 out of 7 children overweight 11. 1 out of 9 teenagers overweight Statistics Health Risks Associated with Obesity *Hypertension *Type @ Diabetes *Cardiovascular disease *Cancer *Degenerative Joint Disease *Low self esteem Evaluating Body Weight Evaluating Body Weight 0. Body Mass Index (BMI) > estimate body fatness, High BMI relates to more chronic disease, cancer, diabetes, high blood pressure 12. Weight for height standard most closely related to body fat content 13. May overestimate in individuals with more muscle tissue & short adults 14. Calculation BMI is inaccurate 0. Body weight (in kilograms/ Height2 (in meters) 1. Weight (in pounds) X 703/ Height2 (in inches) 1. 2. 3. 4. 5. BMI: Overweight and Obesity BMI: Underweight = BMI < 18.5 Healthy weight = BMI 18.5-24.9 Overweight = BMI 25-29.9 Obese = BMI 30-39.9 Severely obese = BMI >40 Body Fat 15. Obesity 6. Excessive amount of body fat > 25 % body fat 7. Increased risk for health problems Increased Cancer, hypertension, diabetes *Desired fat % Women: 21-34 % Men : 8-24% 16. Women 17. Men > 35 % body fat 18.Underwater weighing = hydrostatic weighing Underwater Estimation of Body Fat *Most accurate-> body volume can be calculated *Fat is less dense than lean tissue * Fat floats *Difficult for obese individuals & those with fear of water 2. Air displacement (Bod Pod) 3. Determines the body volume by measuring the space a
person takes up at measurement chamber 4. Displace air in a sealed chamber 4. 0. Body density = body wt / body volume Body 1. % Body fat = ( 495 /body density) - 450 1.
2. Expensive 3. May overestimate in some populations (African American Men) Men) Estimation of Body Fat 19. Skinfold measurement *Need trained Technician *Measures fat under skin *Measure tricep, subscapular, waist, thigh, etc. *Difficult in obese patients It’s not accurate Estimation of Body Fat Estimation 20. Bioelectrical impedance *Low-energy current that measures the resistance of electrical flow *Fat is resistant to electrical flow; the more the resistance , the more body fat has lower electrolyte and water content than muscle 21.DEXA (Dual x-ray phonton absoptionmetry ) 21.
*X-ray body scan that allows for the determination of body fat *Very accurate but expensive -Separates into 3 * fat *fat free soft tissue (muscle) *bone & mineral Body Fat Distribution Body “Pear shape” = Gynold 22.Upper-body obesity, “Apple shape” = Androld (mostly seen in men) 23.Associated with: cardiovascular disease, HTN, Type 2 diabetes Associated
24. Testosterone and excessive alcohol 24. 25.Abdominal fat is released into the liver & promotes inflammation in
the body (which contributes to heart disease) the 26. Defined as Defined 5. Waist measurement of >37 ” for men 5. Waist 6. Waist measurement of >31.5” for women 6. AdultOnset Obesity 27. Develops in adulthood 28. Fewer (number of) adipose cells 29. Adipose cells are larger (store excess amount of fat) 30. If weight gain continues, the number of adipose cells can increase Obesity and Nature Debate : genetic predisposition 7. Identical twins 4. When raised apart still have similar weights 4. 8. Genes Genes 5. Affect metabolic rate, fuel use, brain chemistry, body shape 5. *1 parent obese -> child 40% , 2 parents obese-> child 80% 6. Account for up to 70 % of weight differences 9. 9. Thrifty metabolism gene (we use kcal conservatively) 7. More fat storage to protect against famine Set-Point Theory Set-Point * Weight is regulated by the body Weight * Genetically predetermined body wt * Body resists weight change * Leptin) assists in weight regulation -leptin: hormone that forms communication link between fat cell and the brain, it promotes weight regulation * Reduction in calorie intake results in lower metabolic rate * Ability to shift the set-point weight? NO. Body becomes more efficient at strong fat Opponents of Set-Point Theory Opponents 31. Weight does not remain constant 32.Different environment can alter weight
33. People settle into a particular weight based on current circumstances Obesity and Nurture Debate Obesity * Environmental factors influence weight * Learned eating habits * Activity factor (or lack of) * Poverty & obesity * Female obesity is rooted in childhood obesity * Male obesity appears after age 30 Nature and Nurture Nature 34.Obesity is nurture(the environment)
express itself express allowing nature(genetic) to 35.Location of fat is influenced by genetics 36. Child of obese parents are especially at risk Child 37. Increased physical activity and moderate calorie intake can promote 37. healthy weight healthy Environmental Theory 38. Lack of Exercise *No recess or gym in school *Safety concerns *Sedentary jobs *Busy schedule *Technology – lawn mowers, elevators, escalators Environmental 39. TV, Video games, computer 39. 10. Average 38hours week 10.
11. Requires little energy expenditure 12. Replaces physical activity
Environmental 40.Infrastructure ->environment is underlying foundation 41. Serving sizes (Supersize) 42. Schools 43. Fast Food – US - $600 per person/year spent on fast food (3X higher than any other country (1999)) higher • • • • • • • • • Portion Sizes 12oz soda = 10tsp of sugar (140kcal) 64oz soda = 53 tsp of sugar (742kcal) McDonalds 1950’s = large(1size only) --> 200 kcal (2oz) 1970 = large -->320kcal 1980 = large --> 400kcal 1990 = large -->450kcal Supersize = 540kcal(late 90’s) 2000 = supersize -> 610kcal (7oz) Preventing Childhood Obesity 44. Respect child’s appetite 19% 6-11 y/o overweight 19% 17% 12-18 y/o overweight 45.Avoid high 45. sugar foods 46. Provide ample fiber 47.Limit Limit tv and internet 48. Encourage active play 48. 49. Do not provide food for comfort or reward 50.Parents – role model 51.Children should not diet Children
• • • • • • • • Characteristics of Fad Diets Characteristics Rapid weight loss Testimonials Change diet radically Little or no exercise Diet pills Excludes: whole food groups *need supplement Promises drastic results: 20# wt loss in 1wk Less than 1200kcal * Decrease BMR (they burn fewer calories) * Supplements Looking for a Sound WeightLoss Program? 8. Seek advice from a Registered Dietitian 9. Control calorie intake 10. Increase physical activity 11. Acknowledge need for lifelong changes to maintain healthy weight 11. Characteristics of Successful Diets 52. Slow wt loss 13. 1# week =3500 kcals 53. Exercise and behavior modification
54. All food groups available 14. Key to wt loss and maintenance 55.Permanent realistic lifestyle changes
Do the Math! 8. To lose one pound, you must create a deficit of 3500 kcal 9. So to lose a pound in 1 week (7 days), try cutting back on your kcal intake and increase physical activity so that you create a deficit of about 500kcal per day day week 10. 500 kcal x 7 days = 3500 kcal = ~ 1 pound of weight loss in 1 week Weight Loss Drugs 56. PhenFen 57. Appetite Suppressant 58.Increase serotonin in brain 59. Serotonin decreases appetite 60.Caused heart valve defects, strokes, ceasar, 60. 61.FDA removed from the market 62. Sibutramine (Meridia) 63. Appetite Suppressant *is not broken down – remains high 64.Blocks serotonin reuptake 65.Side Effect – higher blood pressure 66. Xenical * Inhibits production of fat digesting enzyme * Fat consumed is NOT digested * Fat is excreted * Loss of fat-soluble vitamins * GI pain, oily stools * Must follow LOW FAT diet Weight Loss Drugs 67. Long term effectiveness? VARIABLE 68.Side Effects? Headaches, Loose stools , vomiting, heart attacks, 68.
strokes 69.Do you learn new eating habits? Not really Gastric Bypass Surgery 70. Staple off stomach 71. Reattach small intestine 72. Stomach can now hold 24 Tbs Normal stomach can hold 6-8 cups 73. Criteria 73. 15. 16. 17. BMI > 40 BMI between 35 and 40 with obesity related health concerns Obesity present for minimum 5 years, with several nonsurgical attempts to lose wt. 18. No history of alcoholism or major psychiatric disorders. Gastric Bypass Surgery 74. About 75% of pts lose >50% of wt. 75. Cost $20,000$40,000 Gastric Bypass Surgery 76. Complications – Surgery 19. Infections 20. Nutrient deficiencies 20. 21. Bleeding 22. Death Gastric Bypass Surgery 77. Complications 23. Calcium absorption 24. Vitamin B12 absorption 11. risk of osteoporosis risk of osteoporosis 12. Need intrinsic factor in stomach to absorb 13. Injections Freshmen 15 78. All you can eat – cafeteria 79. Reliance on fast food 80.Skipping meals – Late night pizza 81.Lack of exercise 25. Stress 26. Drinks 27.12 oz beer = 140 kcals 28.10 – 12 oz beers =1400 kcals 82. Prevention Freshmen 15 • • • • • • • Stay active Avoid: skipping meals Choose: low fat, high fiber Limit: late night snacking Portion sizes Avoid seconds Alcohol ...
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- Spring '11
- physical activity, body fat, Gastric bypass surgery, body fat content, Body Fat Estimation