2 What Is Obesity?A life-long, progressive, life-threatening, costly, genetically-related, multi-factorial disease of excess fat storage with multiple co-morbidities
3 Obesity is multifactorial: GeneticMetabolicBiochemicalPsychologicalEnvironmentalObesity is a very complex disease that isnot necessarily caused by overeating anda lack of activity and willpower.
4 Risk factors that cannot be changed GeneticsA child born to two obese parents has a 70-80%chance of becoming obeseA child with one obese parent has a 30% chance of becoming obeseA child born to normal-weight parents has a 14%Genetics may influence the number of fat cells in the body, how much and where fat is stored, and resting metabolic rate.
5 GeneticsIn 1994, researchers discovered that mutations in a gene – termed the obesity (ob) gene – prevented the production of leptin, a protein that promotes satiety, reduces appetite, and speeds up metabolism to maintain a normal level of body fat. A second mutation (db) affects the leptin receptor in the hypothalamus resulting in resistance to high leptin levels.
6 GeneticsAnother genetic influence may effect levels of the enzyme, lipoprotein lipase. This enzyme promotes fat storage.Obese people have high LPL activity and are especially efficient at storing fat.
7 Causes of Obesity Without leptin the mouse weighs almost as much as a normalmouse. Withleptin treatmentthe mouse losta significantamount of weight.Copyright 2005 Wadsworth Group, a division of Thomson Learning
8 Fat Cell Development – the number of fat cells increases more rapidly in obese children duringlate childhood and early puberty; fat cells mayexpand or shrink in size, but not their numberwhich is why people with extra fat cells maytend to regain lost weight rapidly; the goal isto prevent fat cell numbers from increasingduring the growing years
9 Fat Cell DevelopmentCopyright 2005 Wadsworth Group, a division of Thomson Learning
10 Risk factors that cannot change MetabolicMetabolism is the process that extracts and utilizes energy from food, including resting metabolic rate and thermogenesisWhether or not obese people have an abnormally slow metabolism is controversial!Set Point Theory – the body may have a mechanismfor keeping weight at a predetermined level of bodyfat. The level of body fat is controlled by the adipostatin the hypothalamus. Actions perceived as voluntary,such as eating and physical activity, may be subtlycontrolled by our adipostat which maintains the setpoint by adjusting appetite, physical activity, and RMRto conserve or expend energy
11 Risk factors that cannot be changed BiochemicalHormonal Abnormalities - endocrine diseases,such as hypothyroidism, polycystic ovarysyndrome, tumors of the pituitary or adrenalglands, insufficient production of sexhormones, insulin-producing tumors of thepancreas are uncommon and rarely a primarycause of obesity, but need to be ruled out.
12 Risk factors that can be changed Dietary IntakeThe “input” side of the energy equationAlthough a reduction in calorie intake isessential for weight loss, to point toovereating as the cause of obesity is overlysimplistic.
13 Risk factors that can be changed Physical ActivityThe “output” side of the energy equationRegular exercise burns calories, buildslean muscle mass, and raises restingmetabolic ratetoo much T.V., computer & car time =too little energy expenditure
14 Risk factors that can be changed PsychologicalLearned behaviors – psychological stimuli, such as boredom, stress, depression, loneliness, may trigger inappropriate eatingWhat purpose does eating/food serve?Hunger is physiological, appetite is psychological - an important distinction to identify reasons for eating other than hunger
15 Risk factors that can be changed EnvironmentOur environment – which includes three-car households, the movement of jobs from farms and mines to offices, TVs & computers in every home, 670-calorie Cinnabons, and supermarkets the size of small cities – makes it too easy to eat more and exercise less.
16 “Genetics loads the gun—the environment pulls the trigger “Genetics loads the gun—the environment pulls the trigger.” George Bray, Courtesy of Ethicon Endo-Surgery, Inc.
17 Measure of Weight Status Height/weight tables do not take into account body composition and are not based on scientific calculations of ideal weight but are derived from ht., wt., mortality data from life insurance companyWeight-for-height – depends on gender & frame size; easy to do but doesn’t always reflect body fatnessIf 10% below median weight = underweightIf 10-20% above standard = overweightIf >20% above standard = obese
18 Measure of Weight Status Obesity is diagnosed by Body Mass Index (BMI) and waist circumference.BMI is a measurement of weight as it relates to height (determined by dividing weight in kilograms by the square of height in meters) and correlates strongly with the amount of body fat and disease risk.BMI = overweightBMI = ObesityBMI >40 = Clinically Severe Obesity
19 Quick Estimation of DBW “Rule of 5’s and 6’s”Men: ’0”Add 6 lbs. Per inchWomen: ’0”Add 5 lbs. Per inch+10% for large frame- 10% for small frame
20 Do You Know Your Own BMI? Weight (lbs) Height 5'4" 5'2" 5'0" 5'10" 5'8"5'6"6'0"6'2"1201301501601701801902002102202302402501402602702802903006'4"
21 Determining BMI using a table is relatively easy but is still only an indirect measure of body fat. It does not take gender or frame size into consideration; at any given BMI women will have more body fat than men.
22 Obesity and Mortality Risk 2.52.0Mortality Ratio1.51.0Very LowVery HighModerateLowModerateHigh2025303540BMIGray DS. Med Clin North Am. 1989;73(1):1–13.
23 Body Fat DistributionCentral Obesity - independent risk factor for obesity-related diseasesWaist circumference reflect body fat distribution; fat accumulation around the abdomen (central obesity) has higher disease risk, especially diabetes and high blood pressure.Waist measurements of 35” or greater (women) and 40” or greater (men) are independent risk factors for obesity-related diseases.
24 Body Fat Distribution “Apple shape” 1. Occurs more in men, postmenopausalwomen, smokers, “heavy drinkers”, &sedentary individuals2. Waist-to-hip ratio – assesses riskwaist (inches)hips (inches)High risk if: Men = > Women= >.8“Pear shape” has lower disease risk
25 Copyright 2005 Wadsworth Group, a division of Thomson Learning
26 Body Composition Assessing body composition – determine body fat by: 1. Fat-fold tests2. Bioelectrical impedance3. Underwater (hydrostatic) weighingWhat should % body fat be?1. Normal for men: 10-22%Absolute minimum: ~5%Health problems if >25%2. Normal for women: 18-32%Absolute minimum: 15%Health problems if >35%
27 Obesity Is a Big Problem! Major public health problem – about to surpass smoking as the #1 leading cause of preventable death in this country!Affects 25% of industrialized worldAmerican statistics:55% (34 million) adults are overweight (BMI > 25) or obese (BMI > 30), 5% severely obese25% of children are overweight7-8% of health care expenditures (>300 billion/year)300,000 deaths annually
28 Obesity Trends* Among U.S. Adults BRFSS, 1985 (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” woman)No Data <10% %–14%
29 Obesity Trends* Among U.S. Adults BRFSS, 1987 (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” woman)No Data <10% %–14%
30 Obesity Trends* Among U.S. Adults BRFSS, 1989 (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” woman)No Data <10% %–14%
31 Obesity Trends* Among U.S. Adults BRFSS, 1991 (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” woman)No Data <10% %– %–19%
32 Obesity Trends* Among U.S. Adults BRFSS, 1993 (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” woman)No Data <10% %–14% %–19%
33 Obesity Trends* Among U.S. Adults BRFSS, 1995 (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” woman)No Data <10% %–14% %–19%
34 Obesity Trends* Among U.S. Adults BRFSS, 1997 (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” woman)No Data <10% %–14% %–19% ≥20%
35 Obesity Trends* Among U.S. Adults BRFSS, 1999 (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” woman)No Data <10% %–14% %–19% ≥20%
36 Obesity Trends* Among U.S. Adults BRFSS, 2001 (*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” woman)No Data <10% %–14% %–19% %–24% ≥25%
37 Obesity Trends* Among U.S. Adults BRFSS, 2002 (*BMI 30, or ~ 30 lbs overweight for 5’4” person)(*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” woman)No Data <10% %–14% %–19% %–24% ≥25%Source: Behavioral Risk Factor Surveillance System, CDC
38 Americans spend millions of dollars every year on antiobesity products in a desperate quest for that “magic potion”.The recidivism rate for weight loss is unacceptably high – partially due to this “quick-fix “ mentality & treatment failure.Many fad diets, over-the-counter drugs, herbal products, and dietary supplements are “gimmicks” and potentially dangerous interventions.
39 Why Treat Obesity? Obesity CANNOT be cured – Improvement in multiple comorbiditiesDecrease in mortality and morbidityImprovement in quality of lifeObesity CANNOT be cured –it CAN be treated and controlled