© 2009 Cengage - Wadsworth
Chapter 9
Weight Management: Overweight, Obesity, and
Underweight
© 2009 Cengage - Wadsworth
Overweight
• Overweight (BMI 25-29.9) and obesity (≥ 30) are widespread health problems that are continuing to increase.
• Many refer to overweight and obesity as an epidemic.
• For good health, weight management is important.
© 2009 Cengage - Wadsworth
© 2009 Cengage - Wadsworth
Overweight
• Fat Cell DevelopmentFat cell numbers
• Fat cell numbers increase most rapidly in later childhood and early puberty.
• Fat cell numbers increase in times of positive energy balance.
• Hyperplastic obesity
© 2009 Cengage - Wadsworth
© 2009 Cengage - Wadsworth
Overweight
• Fat Cell DevelopmentFat cell size
• Fat cell sizes increase when energy intake exceeds expenditure.
• Hypertrophic obesity
The adverse effects of fat in non-adipose tissue are called lipotoxicity.
© 2009 Cengage - Wadsworth
Overweight
• Fat Cell MetabolismLipoprotein lipase promotes fat
storage.Gender differences
• Men are at increased risk for developing central obesity and women are at increased risk for lower body fat.
• Enzymes that break down fats affect men and women differently.
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Overweight
• Set-Point TheoryThe body’s natural regulatory centers
maintain homeostasis at set point.The human body tends to maintain a
certain weight.
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Causes of Obesity
• Obesity may not be as simple as food intake exceeding metabolic needs.
• Some factors, such as overeating and inactivity, are within our control.
• Genetic, hormonal and emotional factors may require professional intervention.
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Causes of Obesity
• Genetics Leptin (also called the ob protein)
• Protein that acts as a hormone to increase energy expenditure and decrease appetite
• Produced by fat cells under the direction of the ob gene
• May be deficient in obese individuals• More research is needed.
© 2009 Cengage - Wadsworth
© 2009 Cengage - Wadsworth
Causes of Obesity
• GeneticsGhrelin
• Protein that acts as a hormone to decrease energy expenditure and increase appetite
• Produced by stomach cells • Has an inverse relationship with PYY
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Causes of Obesity
• GeneticsUncoupling Proteins
• Influence energy metabolism• White adipose tissue stores fat to be used
for energy.• Brown adipose tissue stores fat to be
used for heat.• May oppose the development of obesity
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Causes of Obesity
• Environment – The gene pool of our population remains relatively unchanged.Overeating
• Present and past eating influences current body weight.
• Increased availability of convenient food, large portions, and energy-dense foods
Physical Inactivity• Modern technology replaces physical activities.• Physical activity is important to allow people to
eat enough food to get needed nutrients.
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Problems with Obesity
• Obesity problems depend on many factors such as the extent of overweight, age, health status and genetic makeup.
• Risk factors may differ among individuals.
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Problems with Obesity
• Health risks are evaluated using BMI, waist circumference and disease profiles. Overweight people who are in good health may not
need to lose weight. Obese or overweight people with risk factors could
improve health by losing weight or using other diet and exercise strategies. Risk factors include:
• Hypertension• Cigarette smoking• High LDL• Low HDL• Impaired glucose tolerance• Family history of heart disease• Men ≥ 45 years, women ≥ 55 years
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Problems with Obesity
• Health RisksObese or overweight people with the
following life-threatening-conditions may improve health by losing weight:• Heart disease• Type 2 diabetes• Sleep apnea
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Problems with Obesity
• Perceptions and PrejudicesSocial Consequences
• Prejudices and discrimination• Judged on appearance rather than character• Stereotyped as lazy and lacking self-control
Psychological Problems• Feelings of rejection, shame and depression are
common.• Ineffective treatments can lead to a sense of
failure.
© 2009 Cengage - Wadsworth
© 2009 Cengage - Wadsworth
Problems with Obesity
• Dangerous InterventionsFad Diets
• False theories• Inadequate diets• Can be a danger to health
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Problems with Obesity
• Dangerous InterventionsWeight-Loss Products
• Ephedrine-containing products inhibit serotonin and suppress the appetite. Supplements containing Ephedra have been banned by the FDA due to potential health risks.
• Herbal laxatives do not prevent absorption.• Current laws do not require safety tests and
effectiveness tests for these products.
Other Gimmicks• Don’t work• There is no such thing as cellulite.
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Aggressive Treatments of Obesity
• Individuals with clinically severe obesity and major medical problems may benefit from drugs or bariatric surgery.
• But changing and improving eating and exercise habits offer the greatest benefit.
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Aggressive Treatments of Obesity
• DrugsSibutramine suppresses the appetite
and is most effective when used with a reduced kcalorie diet and increased physical activity. There are many side effects.
Orlistat blocks fat digestion and absorption. There are many side effects.
Other drugs are still under study.
© 2009 Cengage - Wadsworth
Aggressive Treatments of Obesity
• SurgerySurgery is an option for those who have
tried weight loss programs and failed, have a BMI ≥ 35, and are having health problems due to their weight.
Gastric surgery has short-term and long-term problems and requires compliance with dietary instructions.
Liposuction is a popular procedure that is primarily cosmetic but poses risk.
© 2009 Cengage - Wadsworth
© 2009 Cengage - Wadsworth
Weight-Loss Strategies
• A life-long eating plan for good health, which includes nutritionally adequate eating, reasonable expectations, regular physical activity, and permanent lifestyle changes, is best for achieving permanent weight loss.
• Weight loss of 1-2 pounds per week or 10% of body weight in six months is safe.
© 2009 Cengage - Wadsworth
© 2009 Cengage - Wadsworth
© 2009 Cengage - Wadsworth
Weight-Loss Strategies
• Eating PlansBe Realistic about Energy Intake
• 300-500 kcalories/day reduction for BMI between 27 and 35
• 500-1000 kcalories/day reduction for BMI ≥ 35• Dietary Guidelines should be followed.
Diet should be nutritionally adequate while avoiding excessive consumption.
Smaller portions are recommended to feel satisfied, not stuffed.
© 2009 Cengage - Wadsworth
© 2009 Cengage - Wadsworth
Weight-Loss Strategies
• Eating PlansEat foods of lower energy density, that are
high in fiber, high in water and low in fat.Water is important to increase fullness and
reduce hunger.Complex carbohydrates offer abundant
vitamins, minerals and fiber with little fat.Choose fats sensibly and reduce the
quantity of fat.Watch empty kcalories from sugar and
alcohol.
© 2009 Cengage - Wadsworth
© 2009 Cengage - Wadsworth
Weight-Loss Strategies
• Physical Activity An individual’s body weight as well as intensity and
duration of activity influence energy expenditure. Physical activity increases the amount of
discretionary kcalories that can be consumed. Metabolic rates can rise with daily vigorous activity. Activity can decrease body fat and increase lean
body mass. Exercise may help to curb appetite.
Activity can reduce stress and improve self-esteem.
© 2009 Cengage - Wadsworth
© 2009 Cengage - Wadsworth
Weight-Loss Strategies
• Physical ActivityChoosing Activities
• Choose activities that you enjoy and are willing to do regularly.
• Low to moderate intensity for long duration is recommended.
• Daily routines can incorporate energy activities.Spot Reducing
• Regular aerobic exercise and weight loss will help trouble spots.
• Strength training can improve muscle tone.• Stretching can help flexibility.
© 2009 Cengage - Wadsworth
Weight-Loss Strategies
• Behavior and AttitudeBehavior modification requires time and
effort.Awareness of behavior is the first key.Changing behaviors one at a time works best.
• Do not grocery shop when hungry.• Eat slowly.• Exercise while watching television.
Personal attitudes toward food and eating must be understood.
Support groups may be helpful for some people.
© 2009 Cengage - Wadsworth
© 2009 Cengage - Wadsworth
Weight-Loss Strategies
• Weight MaintenanceSuccessful weight-loss maintenance
programs use different criteria so they are difficult to compare.
Vigorous exercise and careful eating plans are key.
Frequent self-monitoring is recommended.
© 2009 Cengage - Wadsworth
Weight-Loss Strategies
• PreventionEat regular meals and limit snacking.Drink water in place of high-kcalorie
beverages.Select sensible portion sizes and limit
daily energy intake to energy expended.
Limit sedentary activities and be physically active.
© 2009 Cengage - Wadsworth
Weight-Loss Strategies
• Public health programs have been suggested to:Develop safety standards for foods.Control commercial advertising.Control conditions under which foods
are sold.Control prices to reduce consumption.
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Underweight
• Incidences of underweight and associated health problems are less prevalent than overweight and obesity problems.
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Underweight
• Problems of UnderweightCauses are diverse.Energy demands may be great and
foods are needed to support growth and physical activities.
Eating disorders are severe cases.
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Underweight
• Weight-Gain StrategiesEnergy-dense foods can be included but
choose fat wisely to avoid the associated cardiac risks.
Regular meals each day must become a priority.
Use large portions and expect to feel full.Consume extra snacks between meals. Juice and milk are easy ways to increase
kcalories.Exercising to build muscles will support
increases in muscle mass.
© 2009 Cengage - Wadsworth
The Latest and Greatest Weight-Loss Diet--Again
© 2009 Cengage - Wadsworth
The Latest and Greatest Weight-Loss Diet--Again
• Fad diets do not offer safe or effective plans for weight loss.
• Diet recommendations should be research based.
• There are guidelines for identifying fad diets and weight-loss scams.
© 2009 Cengage - Wadsworth
The Diet’s Appeal
• There are many misconceptions and distortions of facts.
• Results are not long lasting.
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The Diet’s Achievements
• Don’t Count kCalories • Satisfy Hunger• Follow a Plan• Limit Choices
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The Diet’s Shortcomings
• Too Much Fat• Too Much Protein• Too Little of Everything Else
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The Body’s Perspective
• Adverse side effects of low-carbohydrate, ketogenic dietsNauseaFatigueConstipationLow blood pressureElevated uric acidStale, foul taste in the mouthFetal harm and stillbirth
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