Obesity to Underweight: The Highs and Lows of Weight Status

1. Obesity to Underweight:The Highs and Lows of Weight Status Unit 9

2. Variations in Body Weight • Body processes that favor food intake and body-fat storage developed when “feast and famine” cycles were common • In the US, the proportion of overweight and obese people is increasing, and underweight people decreasing

3. Science defines standards for body weight based on the risk of death Risk increases for the overweight and underweight Weight Status

4. Body mass index (BMI) An indicator of body weight status based on a person’s height Calculated as kilograms per meter squared Estimate of body fat content Body Mass Index Know This:

5. BMI Chart

6. Most US Adults Weigh Too Much • 66% of US adults are overweight or obese • 1 in 6 children are overweight • Overweight • High weight for height • Obese • Condition characterized by excess body fat

7. Overweight and Obesity Increasing

8. Obesity Rates Vary by State

9. Overweight and obesity is becoming a major health problem in the US and around the world Obesity Increasing Worldwide

10. Obesity increases risk of many diseases by altering metabolism Obesity and Health

11. Key Terms • Metabolism • Chemical changes that take place in the body • Example: • Conversion of glucose to energy or to body fat

12. Metabolic Abnormalities • 70% of obese people have metabolic abnormalities that increase disease risk • Hypertension • Elevated triglycerides, glucose, or insulin • Low HDL-cholesterol (“good cholesterol”) • High C-reactive protein (inflammation marker) • 10-15% weight loss decreases risks

13. Key Terms • C-reactive protein (CRP) • Key inflammatory factor produced in the liver in response to infection or inflammation • Elevated concentrations are associated with heart disease, obesity, diabetes, inactivity, infection, smoking, inadequate antioxidant intake

14. Obesity and Psychological Well-Being • Prejudice against children • Unfair treatment from teachers • Isolation, rejection, feelings of inferiority • Prejudice against adults • Discrimination in hiring and promotion • Considered lazy or lacking self-control

15. Body Fat and Health • Health problems associated with obesity are related to where excess fat is stored • Subcutaneous fat • Fat under the skin • Visceral fat • Fat under the skin and muscle of the abdomen Know This:

16. Subcutaneous and Visceral Fat

17. Body Shapes • “Pear shape” • Fat primarily in hips, upper arms and thighs • Less visceral fat, lower risk • “Apple shape” • Fat primarily in abdomen • More visceral fat, higher risk

18. Pear and Apple Shapes

19. Risks From Visceral Fat • Visceral fat is metabolically active and strongly related to many diseases • Causes chronic inflammation, insulin resistance, metabolic syndrome, elevated blood glucose and triglycerides, high blood pressure and hardening of arteries • Leads to heart disease, some cancers, type 2 diabetes, hypertension, fatty liver disease

20. Key Terms • Chronic inflammation • Long-lasting, low-grade inflammation • Inflammation • First response of the immune system to infection or irritation • Triggers release of biologically active substances that promote oxidation and other harmful reactions in the body

21. Key Terms • Metabolic syndrome • A group of metabolic abnormalities characterized by insulin resistance, abdominal obesity, high blood pressure and triglycerides, low HDL cholesterol, impaired glucose tolerance • Predisposes people to type 2 diabetes, heart disease, hypertension, and other disorders • Common in the US (1 in 5 adults) Know This:

22. Key Terms • Insulin resistance • Condition in which cells “resist” the action of insulin in transporting glucose into cells • Fatty liver disease • Fatty infiltration of the liver (≥10% of weight) • Associated with obesity, diabetes, alcoholism • Steatohepatitis (fatty liver with inflammation)

23. Visceral Fat and Waist Circumference • Waist measurements of excess visceral fat: • Men: > 40 inches (102 cm) • Women: > 35 inches (88 cm) • May not accurately measure visceral fat in large, muscular individuals Know This:

24. Determining Waist Circumference

25. Japan requires adults age 50-74 to have yearly waist measurements Determining Waist Circumference

26. Assessment of Body Fat Content • Measures of body fat content are better estimates of health status than BMI • Skinfold thickness measures • Bioelectrical impedance analysis (BIA) • Underwater weighing • Magnetic resonance imaging (MRI) • Computerized axial tomography (CT scan) • Dual-energy X-ray absorptiometry (DEXA) • Whole body air displacement (BOD POD)

27. Assessment of Body Fat Content

28. Assessment of Body Fat Content

29. Assessment of Body Fat Content

30. Assessment of Body Fat Content

31. Assessment of Body Fat Content

32. Assessment of Body Fat Content

33. Body fat has essential functions Hormone manufacture Cell structures Cushions organs Everybody Needs Some Body Fat Know This:

34. What Causes Obesity? • Factors that contribute to excess body fat: • Diet • Physical activity • Environmental exposures • Genetic background • Some medications

35. Born to Be Obese? • Genetic traits influence a person’s susceptibility to becoming obese • Inborn errors in metabolism (rare) • Predisposing traits with environmental triggers • Environmental trigger • Environmental factor such as inactivity, high-fat diet, or high-sodium intake that causes a genetic tendency to be expressed

36. Do Obese Children Become Obese Adults? • 8% of obese 1-2 year olds who do not have obese parents become obese adults • 80% of obese 10-14 year olds who have at least 1 obese parent become obese adults

37. Diet and Obesity • Weight gain results when more energy is consumed than expended • Americans’ calorie intake has risen • Inexpensive, energy-dense foods • Fast-food restaurants, all-you-can-eat buffets • Large portions of food

38. Inactivity and Obesity • Low levels of physical activity contribute to the high and increasing incidence of obesity • Few voluntary activities • Driving instead of walking or biking • TV watching related to childhood obesity

39. Preventing Obesity in Children • Lifestyle changes for the whole family develop healthy eating and activity habits • Nutritious food selections • Fun physical activities • Avoid negative focus on weight

40. Preventing Obesity in Adults • Weight gains likely between ages 25-34 • Slow weight gain (about 1 pound/year) • Some gain large amounts over short periods • Actions need to be taken • Regular vigorous exercise • Reduce portion sizes • Get 8 hours of sleep

41. Changing the Environment • Environmental changes can be made • Limiting access to “junk food” in schools • Requiring calorie labels in fast-food and chain restaurants • Development of urban community gardens • More sidewalks, bicycle and walking paths • Smaller portions and more nutrient-dense foods in restaurants

42. Some People Are Underweight • Causes of underweight in developed nations • Illnesses (HIV/AIDS, pneumonia, cancer) • Eating disorders (anorexia nervosa) • Voluntary food restriction • Poverty • Unhealthy underweight causes fatigue, illness, bone fractures, poor concentration

43. Defining Underweight • Underweight • Low weight-for-height • BMI <18.5 • May represent a deficit of body fat • Men <5% • Women <12% Know This:

44. About 2% of people with low BMIs are genetically thin and healthy, with normal body composition Underweight and Healthy Know This:

45. A nutritious, calorie-restricted diet extends life in mice and monkeys People who voluntarily calorie restrict appear thin but healthy Underweight and Longevity

46. Realistic View of Body Weight • People come in many sizes and shapes

47. Size Acceptance • Natural weights and shapes can’t be modified very much • US obsession with weight and shape promotes eating disorders, social problems • Society can help by accepting people of different weight and sizes

48. The Health at Every Size Program • Health at Every Size Program • Reduces health problems associated with obesity • Reduces blood pressure and LDL-cholesterol • Increases HDL-cholesterol • Improves self esteem and body image • Decreases disordered eating behaviors