Transcript
© 2016 Pearson Education, Inc.
Chapter 9 Lecture
Chapter 9:Achieving andMaintaining aHealthful Body Weight
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Learning Outcomes
1. Define what is meant by a healthful weight.
2. Determine your BMI and fat distribution pattern and identify any health risks associated with these assessments.
3. State the energy balance equation and estimate your basal metabolic rate.
4. Explain how to calculate how many Calories you need to consume on average each day.
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Learning Outcomes
5. Discuss a range of factors thought to contribute to differences in body weight.
6. Identify three key strategies for healthful weight loss.
7. Discuss health risks associated with obesity.
8. Discuss three treatment options for obesity.
9. Identify several factors thought to contribute to the development of eating disorders.
10.Compare and contrast anorexia nervosa, bulimia nervosa, binge-eating disorder, night-eating syndrome, and the female athlete triad.
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Is Your Body Weight Healthful?
• A healthful weight: • is appropriate for your age• is consistent with family history and genetics• is maintained without constant dieting• is compatible with normal blood pressure,
lipid levels, and glucose tolerance• promotes good eating habits and allows for
regular physical activity• is acceptable to you
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Is Your Body Weight Healthful?
• Underweight: having too little body fat to maintain health
• Overweight: having a moderate amount of excess body fat
• Normal weight: having an adequate but not excessive amount of body fat
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Is Your Body Weight Healthful?
• Obesity: having an excess of body fat that adversely affects health
• Morbid obesity: body weight exceeding 100% of normal, creating a very high risk for serious health complications
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Is Your Body Weight Healthful?
• Overweight: BMI between 25.1 and 29.9• Obesity: BMI from 30 to 39.9 • Morbid obesity: weight that exceeds 100% of
normal
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Understand What a Healthful Body Weight Really Is• Determining a person's healthful body weight
should include methods to:– determine the body mass index (BMI)– measure body composition– assess the pattern of fat distribution
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Determine Your Body Mass Index
• Body mass index (BMI)– Compares a person's weight to his or her
height– Gives an indication of a person's overall
health– BMI values below 18.5 or above 30 indicate
increased risks of health problems.
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Measuring Body Mass Index (BMI)
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Measure Your Body Composition
• Body composition– Measurement of body fat and lean body mass– Can be measured by:
• underwater weighing• skinfold measurements• bioelectric impedance analysis (BIA)• dual-energy X-ray absorptiometry (DX)• Bod Pod
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Assess Your Fat Distribution Patterns
• Fat distribution pattern– Measured by waist-to-hip ratio – Apple-shaped fat patterning: upper body
obesity• Increased risk for chronic diseases
– Pear-shaped fat patterning: lower body obesity• No significant increased risk for chronic diseases
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Fat Distribution Patterns
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What Makes Us Gain or Lose Weight?
• Whether a person gains or loses weight depends on:– energy intake vs. energy expenditure– genetic factors– childhood weight– behavioral factors– social factors
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Energy Balance
• Energy balance– Occurs when energy intake = energy
expenditure– Energy intake = kcal from food– Energy expenditure = energy expended at
rest, during physical activity, and as a result of eating food
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Energy Imbalance: Weight Loss
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Energy Imbalance: Weight Gain
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Energy Balance: Weight Maintenance
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Energy Output From All Sources
• Basal metabolic rate (BMR)– Energy expended to maintain basal, or
resting, functions of the body– Basal metabolism is the highest proportion of
total energy expenditure.– More lean tissue increases your BMR.– BMR decreases with age.
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Energy Output From All Sources
• Thermic effect of food – Energy expended for the body to process food
• Total energy expenditure = – basal metabolic rate– plus thermic effect of food– plus energy cost of physical activity
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Factors Influencing BMR
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Energy Expenditure Components
Insert Figure 9.6 from the Text
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How Many Kilocalories Do You Need?
• The most accurate way to determine your energy needs:– Calculate your BMR.
• BMR = (weight in pounds / 2.2) x 24
– Factor in your activity level.• No activity: multiply BMR by 1.2• Moderate activity: multiply BMR by 1.5• Intense activity: multiply BMR by 1.75
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Energy Costs of Selected Activities
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Genetic Factors Affect Body Weight
• Nongenetic, environmental factors account for 10–50% of BMI.
• Different ideas have been suggested to explain the impact of genetics on body fat.– FTO gene – Thrifty gene theory– Set-point theory
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Genetic Factors Affect Body Weight
• FTO Gene• Fat mass and obesity-associated gene• Stimulates excessive food intake• May diminish feelings of satiety• Physical activity may reduce the influence of
FTO.
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Genetic Factors Affect Body Weight
• Thrifty gene theory– Proposes that a gene (or genes) causes
people to be energetically thrifty– Proposes that people with this gene expend
less energy than other people and therefore gain weight
– A "thrifty gene" has not been identified.
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Genetic Factors Affect Body Weight
• Set-point theory– Proposes that each person's weight stays
within a small range (set point)– The body compensates for changes in energy
balance and keeps a person's weight at his or her set point.
– Long-term changes to diet and physical activity may change the set point.
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Physiologic Factors Affect Body Weight
– Leptin, a protein hormone produced by adipose cells, reduces food intake.• Some people may be leptin resistant.
– Ghrelin is a protein synthesized in the stomach that acts like a hormone and plays a key role in appetite regulation.
– Cholecystokinin (CCK) promotes satiety.
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Physiologic Factors Affect Body Weight
• Neuropeptide Y produced in hypothalmaus decreases satiety.
• Uncoupling proteins are found in cells' mitochondria and may play a role in energy production.• Found in brown adipose tissue
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Cultural and Economic Factors
• Cultural factors affect our food choices.– Religious beliefs, learned food preferences,
and food-related values• Cultural factors promote inactivity.• Economic status is related to health status.
– Does eating healthful always have to be more expensive?
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Social Factors
• Social factors influencing our diet include:– family or cultural traditions– holidays and celebrations– easy access to high-fat foods– less physically active lifestyles– societal expectations of the "perfect" body
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Social Factors
Click on the Control of Appetite link separate from
the power point.
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Achieve and Maintain Healthful Weight
• Healthful weight change requires:– gradual reduction in energy intake– regular and appropriate physical exercise– application of behavior modification
techniques
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Achieve and Maintain Healthful Weight
• For effective weight loss, one should:– avoid fad diets– set realistic weight-loss goals– eat smaller portions of lower-fat foods– participate in regular physical activity– adopt sound behavior modifications into daily
life
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Achieve and Maintain Healthful Weight
1. Why do you think the Weight Watchers program has been so successful? What role does social support play in the program?
2. What are some recommendations or strategies for those who want to lose weight but cannot afford Weight Watchers?
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Achieve and Maintain Healthful Weight
• Choose a diet plan based on three strategies:– Does the plan promote gradual reduction in
energy intake?– Does the plan advocate increased physical
activity?– Does the plan include strategies for behavior
modification?
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Achieve and Maintain Healthful Weight
• Weight-loss plans take many forms:– Fad diets (avoid these)– Moderate fat, high carb, moderate protein
• Weight Watchers, Jenny Craig
– High fat, low carb, high protein• Atkin's, Carb Addict's Diet, Protein Power
– Low fat or very low fat• Dr. Dean Ornish's Program, New Pritikin Program
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Achieve and Maintain Healthful Weight
• Set realistic goals.• Eat smaller portions of lower-calorie foods.• Participate in regular physical activity.• Incorporate appropriate behavior modifications
into daily life.
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Achieve and Maintain Healthful Weight
1. Discuss the practical methods used for keeping weight off.
2. Discuss psychological factors or contributors for the inability to maintain weight loss.
3. What tips would you give someone who wanted to lose weight safely and to maintain weight loss?
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How Can You Avoid Obesity?
• Obesity is a major health concern linked to many chronic diseases, including:• Hypertension• Type 2 diabetes• Stroke• Osteoarthritis• Cancer• Depression• Fetal complications
and deaths
• Unhealthy cholesterol levels
• Heart disease• Gallbladder disease• Sleep apnea• Menstrual
problems/infertility• Alzheimer's disease
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How Can You Avoid Obesity?
Click on the Obesity Rates link separate from the power
point.
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Abdominal Obesity
Insert Figure 9.10 from Text
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Why Do People Become Obese?
• Obesity is a multifactorial disease–many things cause it.
• Contributing factors can include:– genetics– physiology– childhood overweight and obesity– social factors
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Does Obesity Respond to Treatment?
• Treatments for obesity may include lifestyle changes, such as:– reduced-energy diet and increased level of
physical exercise– prescription medications– surgery
• gastroplasty• gastric bypass• gastric banding
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Does Obesity Respond to Treatment?
• Weight loss medications and herbal supplements:– should only be used with a physician's
supervision– may have dangerous side effects– should only be used by severely obese
people
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Does Obesity Respond to Treatment?
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Does Obesity Respond to Treatment?
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Does Obesity Respond to Treatment?
Next slide to view video.
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Does Obesity Respond to Treatment?
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What If You Are Underweight?
• Effective weight gain should include:– eating 500 to 1,000 extra kcal/day– eating frequently throughout the day– maintaining a balanced diet, limiting fat intake
to 25–35% of total energy intake– avoiding tobacco products– regular exercise with resistance training
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Disordered Eating: Are You At Risk?
• Eating disorders are not the same as disordered eating.– Disordered eating: variety of abnormal or
atypical eating behaviors used to reduce weight
– Eating disorder: psychiatric condition involving extreme body dissatisfaction and long-term eating patterns harming the body
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Disordered Eating: Are You At Risk?
• Two common eating disorders:– Anorexia nervosa: disorder of self-starvation
eventually leading to severe nutrient deficiency
– Bulimia nervosa: eating disorder characterized by extreme overeating followed by behaviors to prevent weight gain
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Disordered Eating: Are You At Risk?
• Body image: the way you perceive your body• People's attitudes toward eating and body image
occur on a continuum from normal eating/full body acceptance, to disordered eating/total lack of body acceptance.
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Disordered Eating: Are You At Risk?
• Multiple factors may contribute to the development of an eating disorder.– Family environment– Unrealistic media images– Sociocultural pressures– Personality traits– Genetic and biological factors
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Anorexia Nervosa
• Anorexia nervosa: serious, potentially life-threatening eating disorder in which unhealthful behaviors are used to maintain a very low body weight– 0.3%–3.7% of U.S. females will develop
anorexia.– At least 4% of females with anorexia will die
from complications.
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Anorexia Nervosa
• Symptoms– Extremely restrictive eating practices– Self-starvation– Intense fear of weight gain– Amenorrhea: no menstrual periods for at
least 3 months– Unhealthful body image
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Anorexia Nervosa
• Health risks– Energy deficiency– Nutrient deficiencies– Electrolyte imbalances can lead to heart
failure and death.
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Bulimia Nervosa
• Bulimia nervosa: eating disorder characterized by binge eating followed by purging
• Binge eating: eating a large amount of food in a short period of time
• Purging: an attempt to rid the body of unwanted food by vomiting, laxatives, fasting, excessive exercise, or other means
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Bulimia Nervosa
• Affects women more than men.• Can be seen in male athletes who are required
to keep their body weight low.• 1% of bulimia patients will die from
complications.
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Bulimia Nervosa
• Symptoms– Chronically inflamed and sore throat– Swollen glands in neck and below jaw– Worn tooth enamel– Gastroesophageal reflux disorder– Kidney problems from diuretic abuse– Severe dehydration from purging of fluids
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Bulimia Nervosa
• Health risks– Electrolyte imbalance; caused by dehydration
and loss of sodium and potassium ions from vomiting
– Gastrointestinal problems– Dental problems
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Anorexia Nervosa
Insert Figure 9.13 from Text
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Binge-Eating Disorder
• In binge-eating disorder, binging occurs on average twice a week or more, and is usually not followed by purging, often resulting in significant weight gain.
• Affects 2% of adult population.• Might be as high as 30% among the obese
population.
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Eating Disorder Syndromes
• Night-eating syndrome is linked to insomnia and obesity.
• Female athlete triad: serious medical syndrome frequently seen in female athletes consisting of:• disordered eating• menstrual dysfunction• osteoporosis
• Seen especially in sports that emphasize leanness or a thin body build
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The Female Athlete Triad
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EDNOS – A Rare Eating Disorder
1. Discuss the signs and symptoms of EDNOS.
2. Discuss types of treatment used to treat EDNOS.
3. What are your reactions to the method of having the women in the treatment clinic eat foods that may not be the healthiest (i.e., pizza, Chinese food)? In your opinion, is this the best method of treatment? Why or why not?
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Orthorexia
Next slide to view video.
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Treatment for Disordered Eating
• Successful treatment for eating disorders usually involves a team approach, including:– patient– physician– nutritional and psychiatric counselors– coach– family and friends
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