© 2010 Pearson Education, Inc. Chapter 15: Weight Management and Disordered Eating.

© 2010 Pearson Education, Inc.

Chapter 15: Weight Management and Disordered Eating


The Status of Obesity in America

In the early 1960s, fewer than 32% of Americans were overweight

Today, 67% of Americans are overweight

• More than 33% of adults and 16% of children are obese Americans spend over $45 billion annually on weight-loss

solutions Medical complications associated with overweight cost the

U.S. health care system $92 billion annually


What Is Weight Management and Why Is It Important?

Weight management is maintaining body weight in a healthy range

• BMI 18.5–24.9 Underweight and overweight

can both be of concern


What Is Weight Management and Why Is It Important?

Underweight increases risk for

• Low body protein and fat stores

• Depressed immune system Overweight and obesity

• Can increase risk of numerous health problems

• Can expose individuals to increased social, educational, and economic disadvantages

Healthy People 2010 aims to reduce overweight and obesity in adults to less than 15% and to 5% in children and adolescents


Quick Review

Weight management means maintaining a healthy weight (BMI 18.5–24.9) to reduce risk of certain health problems

Both underweight and overweight are associated with increased health risks

Obesity and underweight are associated with negative social and psychological effects including discrimination, low self-esteem, depression, suicide, and alcohol and drug problems

Reducing overweight and obesity are two of the Healthy People 2010 national health objectives


How Do Fat Cells Form and Expand?

Growth of fat cells (adipocytes) occur in two ways

• Can expand to store more fat (hypertrophy)

• Once filled to capacity, stimulate the production of more fat cells (hyperplasia)



Average adult has 30–50 billion adipocytes which hold 0.4–0.5 micrograms of fat each

• Adipocytes of obese individuals store 0.6–1.2 micrograms of fat per cell

• Weight loss leads to shrinking the size of adipocytes, but no change in the number of cells

Hyperplasia slows with age, but growth and production of fat cells continues throughout life

Figure 15.1

The Formation of Adipocytes



Enzymes control the size of fat cells

• Lipoprotein lipase (LPL) increases lipogenesis

• Hormone-sensitive lipase (HSL) stimulates lipolysis Heavier people have increased activity of LPL

• Men: LPL more active in visceral, abdominal fat cells

• Women: LPL activity higher in hips and thighs


Quick Review

The average adult body contains 30–50 billion adipocytes When adipocytes reach their maximum capacity to store

fat, new cells form Obese individuals have more fat cells storing a greater

quantity of fat LPL and hormone-sensitive lipase are enzymes that

influence the balance between lipogenesis and lipolysis The activity of these enzymes differs in overfat and lean

individuals and in men and women


How Is Food Intake Regulated?

Hunger and satiation are controlled by hormones that are produced in the brain and gastrointestinal tract

Appetite is the desire to eat food whether or not there is physical hunger; may be triggered by factors such as time of day, social occasions, emotions, or the sight or smell of food

© 2010 Pearson Education, Inc. Figure 15.2


Two regions within the hypothalamusof the brain control hunger and satiety

• Ventromedial nucleus

• Lateral hypothalamus



After a meal, satiety is triggered in the ventromedial nucleus

• Stretch receptors in the stomach signal fullness

• Cholecystokinin and peptide YY send feedback to the hypothalamus to increase satiety and decrease hunger

• Nutrient absorption triggers insulin release which also decreases hunger

• Leptin, produced by adipose tissue, both suppresses hunger and promotes energy expenditure



The lateral hypothalamus controls hunger

• Ghrelin, produced by the stomach, stimulates hunger during fasting or on a low-kilocalorie diet

• Neuropeptide Y is produced in the hypothalamus and activated by ghrelin; it stimulates hunger and LPL activity

In addition to hormones, certain macronutrients, especially protein, promote satiety and reduce food intake


Quick Review

Food intake is controlled by hunger, satiety, and appetite Within the brain, the ventromedial nucleus controls satiety

and the lateral hypothalamus controls hunger Neuropeptides, hormones, and neural signals from the

gastrointestinal tract and adipocytes communicate hunger and satiety to the hypothalamus

Leptin and ghrelin play key roles in triggering hunger and satiety, with ghrelin triggering hunger and leptin triggering satiation


Genetics in Obesity and Weight Management

Genetics can make the body more susceptible to weight gain or weight loss• Genetic differences in the level or functioning of some

hormones such as leptin and ghrelin• Differing responses to environment and availability of

food• Different rates of nonexercise activity thermogenesis

(NEAT)• Genetic “set point” theory that individuals have a

genetically established body weight and deviation from this point will stimulate changes in metabolism to reestablish the normal weight


Environment in Obesity and Weight Management

Environmental factors can increase appetite and decrease physical activity

• Gene-environment interaction – the interaction of genes and the environment increases risk of obesity in susceptible individuals

• Lack of time results in Americans turning to high-calorie convenience foods or dining out

• An abundant food supply and portion distortion result in people eating more

• Decreased physical activity and increased sedentary behavior means Americans are burning fewer calories


Quick Review

Genetic influences play a role in weight management including influencing the levels of the hormones leptin and ghrelin

Environmental factors, including lack of time, an abundant food supply, portion distortion, and lack of physical activity, encourage obesity

© 2010 Pearson Education, Inc. Figure 15.3

How Can You Lose Weight Healthfully?

Overweight individuals should aim to lose 10% of their body weight over 6 months

The keys to long-term weight management

Figure 15.5

The Volume of Food

How Can You Lose Weight Healthfully? Devote 60 to 90 minutes daily to moderate-intensity

physical activity to aid in weight loss, prevent weight gain


Quick Review

The keys to successful long-term weight loss include reducing daily kilocalorie intake, increasing physical activity, and changing behaviors

Meals of low-energy density, high-volume vegetables, fruits, and fiber along with lean protein and healthy oils promote satiety and reduce unplanned snacking

Daily physical activity facilitates weight loss Changing unhealthy habits by removing certain

environmental cues supports healthy eating habits


How Can Weight Loss Be Maintained?

Setting realistic weight goals is essential to prevent false hope syndrome and risk of dropping a weight-loss program

Weight cycling is thought to lead to problems such as hypertension, gallbladder disease, and elevated cholesterol

After weight loss, a person will have lower energy needs because there is less body weight to maintain; this is known as the “energy gap” phenomenon

• Increasing daily physical activity is the easiest way to close the energy gap and overcome weight loss plateaus

Some individuals with a BMI > 40 are candidates for extreme treatments to lose weight


Extreme Measures for Extreme Obesity

A very low-kilocalorie diet

• Is a short-term solution for individuals at high risk of disease related to obesity

• Requires vitamin and mineral supplementation and medical supervision

Weight-loss medications

• Sibutramine (Meredia) – suppresses appetite

• Orlistat (Xenical) – inhibits fat absorption


Extreme Measures for Extreme Obesity

Surgery

• Gastric bypass

• Gastric banding

• Liposuction


Quick Review

Setting realistic weight-loss goals will prevent the false hope syndrome associated with trying to achieve goal weight too quickly

Exercise improves muscle mass, prevents a decline in basal metabolism, and helps overcome weight loss plateaus

Eating less or exercising more helps close the energy gap following weight loss

For individuals with a BMI greater than 40, more extreme weight loss treatments may be indicated


What Is the Healthiest Way to Gain Weight?

Eat sufficient energy to meet basal needs plus fuel for the exercise needed to stimulate muscle synthesis

Focus on a variety of energy-dense, nutritious food choices Eat larger portions at meals and energy-dense snacks

during the day Add at least 500 kilocalories daily for weight gain of about

one pound per week Regular exercise and resistance training stimulate muscle

growth and help to avoid excess fat storage

Figure 15.7

More- and Less-Energy-Dense Food Choices


Quick Review

Weight gain can be as challenging and frustrating as trying to lose weight

People who want to gain weight need to consume additional kilocalories through energy-dense food to take in more energy than they expend

Increasing portion sizes and adding nutrient-dense snacks helps to increase total intake

Add resistance exercise to build muscle mass


What Is Disordered Eating?

Disordered eating describes abnormal and potentially harmful eating patterns

Eating disorders are psychological illnesses diagnosed by meeting specific criteria that include disordered eating behaviors and other factors

Eating disorders affect over 1 million U.S. individuals


Health Consequences of Disordered Eating

Health consequences of anorexia nervosa include

• Electrolyte imbalances

• Drop in heart rate and blood pressure, weakness and fatigue, hair loss

• Slowing of the digestive process

• Inadequate nutrient intake and possible deficiencies


Health Consequences of Disordered Eating

Health consequences of bulimia nervosa include

• Tears in the esophagus

• Tooth decay and gum disease from stomach acid

• Electrolyte imbalances

• Dehydration and constipation

• Impaired normal bowel function through laxative use


Eating Disorders Not Otherwise Specified

Binge eating disorder

• Characterized by recurrent episodes of binge eating without regard to physiological cues

• May eat for emotional reasons resulting in out-of-control feeling while eating and physical and psychological discomfort after eating

• May eat in secret and feel ashamed about their behavior

• Negative health effects are those associated with obesity such as high blood pressure, high cholesterol, heart disease, type 2 diabetes, and gallbladder disease


Eating Disorders Not Otherwise Specified

Night eating syndrome • A person consumes a majority of daily kilocalories after

the evening meal and wakes up during the night to eat• Typically does not have an appetite during morning

hours• Is a unique combination of disordered eating, a sleep

disorder, and a mood disorder• Stress is a contributing factor to the development and

continuation of the disorder• May feel guilty, ashamed, or embarrassed while eating at

night as well as the next morning• Most often in young adults 18–30 years old


How Are Eating Disorders Treated?

Effective treatment requires a multidisciplinary team approach including

• Psychological professionals

• Medical professionals

• Nutrition professionals As some eating disorders can be life-threatening, a

physician should closely monitor treatment


How Are Eating Disorders Treated?

A Registered Dietitian can help someone with an eating disorder establish normal eating behaviors

Nutritional approaches include

• Meal planning

• Using food journals

• Identifying binge triggers, safe and unsafe foods

• Recognizing hunger and fullness cues Full recovery from eating disorders is possible and most

successful when the disorder is treated in the early stages


Quick Review

Disordered eating is characterized by an abnormal eating pattern

Eating disorders include disordered eating and other diagnostic criteria

Over 11 million Americans struggle with eating disorders Eating disorders include anorexia nervosa, bulimia nervosa,

binge eating or compulsive overeating, and night eating syndrome

Recovery is possible, particularly if treatment is sought in the early stages of the disorder


Putting It All Together

Maintaining a healthy body weight reduces the negative physical and psychological effects of obesity

Hunger and satiety are regulated by the hypothalamus of the brain through neuropeptides, hormones, and neural signals from the gastrointestinal tract and adipocytes

Both genetic and environmental factors influence obesity and weight management

Diet, physical activity, behavior modification are the keys to long-term weight management

Eating disorders include anorexia nervosa, bulimia nervosa, binge eating or compulsive overeating, and night eating syndrome

Treatment of eating disorders requires a multidisciplinary team approach

© 2010 Pearson Education, Inc. Chapter 15: Weight Management and Disordered Eating.

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Transcript of © 2010 Pearson Education, Inc. Chapter 15: Weight Management and Disordered Eating.