chapter 14

© 2012 McGraw-Hill Higher Education. All rights reserved.

Chapter 14


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Introduction

National Institutes of Health68% of American adults are overweight2007-2008: 33.8% of adult men and 35.5% of

adult women were obeseManaging body weight

○ Balance calories in with calories expended○ Focus on long-term goals, change in lifestyle○ Manage nutrition, physical activity, stress control


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Figure 14.1 Obesity Prevalence, by Age and Sex, of American Adults, 2007-2008


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Basic Concepts of Weight Management

One pound of fat = 3,500 calories Body composition

Fat-free mass (or lean body mass)Body fat

○ Essential fat 3-5% of total body weight in men, 8-12% in women Amount of fat stored depends on many factors:

- Gender- Age- Heredity- Metabolism- Diet - Activity level

Overweight: total body weight above recommended rangeObesity: a more serious degree of overweight


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Energy Balance

Crucial to keep a healthy ratio of fat to fat-free massEnergy (calories from food)Consumption and/or expenditure of caloriesControl over intake of caloriesNegative energy balancePositive energy balanceNeutral energy balance


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Figure 14.2 The Energy Balance Equation


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Evaluating Body Weight andBody Composition Body mass index (BMI) Measure of body weight for classifying health risks Weight should be proportional to height Drawbacks of BMI Does not distinguish between fat weight and fat-free weight


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Assessment of Body Weight National Institutes of Health categories of BMI

Under 18.5 is classified as underweight Between 18.5 and 24.9 is healthy (normal) Between 25 and 29.9 is overweight Between 30 and 34.9 is obese (Class I) Between 35 and 39.9 is obese (Class II) 40 or greater is extreme obesity (Class III) Under 17.5 is sometimes used as a diagnostic criterion for anorexia nervosa

BMI Measurement. Example: 5’3” tall (63 inches), 130 pounds1. Divide your body weight in pounds by 2.2 to convert the amount to kilograms:

130 / 2.2 = 59.12. Multiply height (in inches) by 0.0254 to convert to meters:

63 X 0.0254 = 1.6

3. Multiply the result of step 2 by itself to get the square of the height measurement:1.6 X 1.6 = 2.56

4. Divide the result in step 1 by the result in step 3 to determine your BMI:BMI = 59.1 / 2.56 = 23.0

Alternative equation based on pounds and inchesBMI = [weight / (height x height)] x 703


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Figure 14.3 Body Mass Index (BMI)


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Body Composition Analysis Most accurate way to evaluate body composition

is to determine percent body fat Hydrostatic (underwater) weighing and Bod Pod Skinfold measurements

Thickness of fat under the skin Bioelectrical Impedance Analysis

Electricity prefers fat-free tissue Scanning procedures

CT scan, MRI, dual-energy X-ray, dual-photon absorptiometry, infrared reactance, total body electrical conductivity


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Table 14.2 Percentage of Body Fat as the Criterion for

Obesity


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Excess Body Fat and Wellness Health risks of excess body fat

Obese individuals have a mortality rate twice that of non-obese○ Reduces life expectancy by 10-20 years○ Associated with: unhealthy cholesterol and triglycerides,

impaired heart function, death from cardiovascular disease○ Other health factors: hypertension, cancer, impaired immune

function, gallbladder and kidney disease, skin problems, impotence, sleep disorders, back pain, arthritis, complications with pregnancy, menstrual irregularities, urine leakage, increased surgical risk, psychological problems

○ Strong association : Type 2 diabetes


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Figure 14.4 Diabetes Mellitus


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Body Fat Distribution and Health

Apple shape Android obesityUpper regions of their bodiesIncrease risk of high blood pressure, diabetes, early-

onset heart disease, stroke, cancer Pear shape

Gynoid obesityFat storage in the hips, buttocks and thighs

Assessed by measuring waist circumferenceRisk for men: waist measurement over 40 inchesRisk for women: waist measurement over 35 inches


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Body Image

Collective picture of the body as seen through the mind’s eyePerceptionsImagesThoughtsAttitudesEmotions


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Problems Associated with Very Low Levels of Body Fat Less than 8-12% for women and less than

3-5% for men Extreme leanness linked to problems

Reproductive Circulatory Immune system disorders

Female Athlete Triad1. Abnormal eating patterns2. Amenorrhea3. Decreased bone density


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What Is the Right Weight for You? General guides

BMI Percent body fat Waist circumference measurement

Let your lifestyle be your guide1. Eat moderate amounts

2. Get plenty of exercise

3. Think positively

4. Learn to deal with stress


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Factors Contributing to Excess Body Fat

Genetic factorsNutrigenomics

○ Study of how nutrients and genes interactGenetics 25-40% of an individual’s body fat600 genes have been linked to obesity

Physiological FactorsResting metabolic rate (RMR)HormonesFat cells


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Lifestyle Factors Eating Physical Activity Psychosocial factors

Emotions○ Distraction from difficult feelings○ Helps regulate emotions○ Coping strategies

Socioeconomic status Family and cultures


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Adopting a Healthy Lifestyle for Successful Weight Management “Normal” body weight Diet and eating habits

Total calories○ MyPyramid suggestions○ Best approach for weight loss is combining an

increase of exercise with moderate calorie restriction○ Do not go on a crash diet


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Adopting a Healthy Lifestyle for Successful Weight Management

(continued) Portion sizes Energy (calorie) density Eating habits

Eat small, frequent mealsDon’t skip mealsConsume most calories in daytime


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Physical Activity and Exercise 30 minutes or more of moderate-intensity

physical activity every dayWalkingGardeningHouseworkWalking 1 mile in 15-20 minutes


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Thinking and Emotions

What do you think of yourself? Self-esteem Negative emotions “Ideal self” Beliefs and attitudes you hold


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Coping Strategies Adequate and appropriate strategies Don’t use food as a way to cope with stress

Good communicationAdequate exercisePositive thinking and emotionsEffective coping strategies and behavior

patterns


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Approaches to Overcoming a Weight Problem

Doing it yourself○ 0.5-2.0 pounds per week○ Initial weight loss from fluids○ Very low calorie diets need to be avoided

Diet books○ Reject books with gimmicks or rotating levels of calories○ Accept books that advocate a balanced approach

Diet supplements and diet aids○ Formula drinks and food bars○ Herbal supplements○ Other supplements


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Weight-Loss Programs

NoncommercialTOPS (Take Off Pounds Sensibly)OA (Overeaters Anonymous)

○ 12-step program with spiritual orientation

Commercial Online Clinical


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Weight-Loss Programs Prescription drugs

Appetite suppressants control appetiteAll have potential side effectsOnce drugs are stopped, most return to original

heavy weightGood option for very obese who need help getting

started - permanent life style changeTwo drugs approved for longer-term use:SibutramineOrlistat (Xenical)


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Surgery Severely obese –

5.7% of adult Americans is “morbidly” obeseNIH recommends gastric bypass for individuals

with a BMI of 40 or higherRoux-en-Y gastric bypassVertical banded gastroplasty (VBG)Lap-Band – variation of VGB

○ Adjustable bandLiposuction


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Body Image

Severe body image problems○ Body dysmorphic disorder (BDD)

Affects about 2% of AmericansUsually before age 18

○ Muscle dysmorphia

Acceptance and change Know when the limits to healthy change have

been reached Know the unrealistic cultural ideal


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Eating Disorders Problems with body weight and weight

control Characterized by severe disturbances in

body image, eating patterns, and eating-related behaviors

Disordered eating affects an estimated 10 million American females and 1 million males


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Eating Disorders

Central feature – dissatisfaction with body image and body weight created by distorted thinking

HeredityOver 50% of the risk

Turning points in lifeCoping with stress


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Eating Disorders Anorexia Nervosa - failure to eat enough food Affects 3 million people – 95% are female

Typically develops between the ages of 12 and 18 Characteristics

Fear of gaining weight Distorted self-image Compulsive behaviors and rituals Excessive exercise

Health risks of anorexia nervosa Stop menstruation Intolerant of cold Low blood pressure and heart rate Dry skin Hands and feet may swell and take on a blue tinge Depression and suicide

Medical complications Disorders of the cardiovascular, gastrointestinal, endocrine, and

skeletal systems


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Eating Disorders Bulimia NervosaBulimia Nervosa - recurring episodes of binge eating followed by purging Begins in adolescence or young adulthood

Increasingly younger (11-12 years) and older (40-60 years) ages

CharacteristicsRapidly consumes food, then purgesDone in secretAfter a binge, feels ashamed, disgusted, and drained both physically and emotionally

Health risksErodes tooth enamelDeficient calorie intakeLiver and kidney damageCardiac arrhythmiaChronic hoarsenessEsophageal tearingRupture of the stomachMenstrual problemsIncreased depression


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Eating Disorders

Binge-eating disorder (BED) - similar to bulimia, except no purging behaviorAffects about 2% of American adultsUncontrollable eating, usually followed by

guilt and shameOften eat as a way of copingLikely to be obeseHigh rates of depression and anxiety


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Borderline Disordered Eating Eating habits and body image run along a

continuum from healthy to seriously disorderedSome have symptoms of disorderDo not meet full diagnostic criteria for disorderBehaviorsDanger signsSeek help


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Treating Eating Disorders Combination of psychotherapy and medical management Address eating disorder, misuse of food, and managing

emotions Anorexia nervosa

○ Avert a medical crisis Adequate body weight

○ Psychological aspects Bulimia nervosa

○ Stabilize the eating patterns○ Identify and change thinking patterns○ Improve coping skills○ Drug treatment:

Binge-eating○ Similar treatment protocol as bulimia nervosa


Chapter 14

chapter 14

Health & Medicine

body fat distribution

percentage of body fat

right weight

energy balance equation

diabetes mellitus

obesity prevalence

lifestyle factors

isobeseclassi between35and39