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Obesity and Eating Disorders
Chapter 14
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Obesity and Eating Disorders
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Prevalence of obesity (BMI ≥30) in American adults aged 20 and older has almost tripled from
13% to 31.4% over the last 40 years
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One of the most common causes of preventable death
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A far less common weight issue is disordered eating manifested as anorexia nervosa or bulimia
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Historically the study of obesity and eating disorders has been separate
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Commonalities between them
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Obesity
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Overweight is defined as having a BMI ≥25
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Related to an excessive body weight, not necessarily excessive body fat
Obesity is defined as having a BMI ≥30
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Generally assumed to be related to an excessive amount of body fat
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Obesity (cont’d)
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Causes of obesity
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Occurs when people eat more calories than they expend over time
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Why it occurs is not fully understood
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“Set point” theory of weight control
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Some people are able to burn hundreds of extra calories in the activities of daily living to
help control weight
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Likely that a combination of genetic and environmental factors is involved
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Obesity (cont’d)
Genetics
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More than 300 genes have been linked to obesity
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About 30% to 40% of the variance in BMI is attributed to genetics
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About 60% to 70% is attributable to environment
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Genetics are involved in:
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How likely a person is to gain or lose weight
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Where body fat is distributed
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Response to overeating
Obesity (cont’d)
Environment
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Rise in obesity without change in gene pool
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Root cause is lifestyle and environment, not biology
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Environmental influences include:
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Abundance of palatable, low-cost, high-calorie– density foods that are readily
available in prepackaged forms and in fast food restaurants
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Increasing consumption of soft drinks and snacks
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Great proportion of food expenditures spent on food away from home
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Obesity (cont’d)
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Environment (cont’d)
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Influences include:
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Growing portion size of restaurant meals
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Low levels of physical activity
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Increases in television watching
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Widespread use of electronic devices in the home, such as computers and video
games
All lead to sedentary lifestyle
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Obesity (cont’d)
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Environment (cont’d)
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Gene–environment interaction
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Complications of obesity
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Most common complications of obesity include:
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In people with a genetic predisposition to obesity, the severity of the disease is
largely determined by lifestyle and environmental conditions
Insulin resistance, type 2 diabetes, hypertension, dyslipidemia, cardiovascular
disease, stroke, gallstones and cholecystitis, sleep apnea, respiratory
dysfunction, and increased incidence of certain cancers
Obesity (cont’d)
Complications of obesity (cont’d)
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Increases the risk of complications during and after surgery
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Obesity is considered to be a major contributor to preventable deaths in the United
States
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Obesity presents psychological and social disadvantages
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Negative social consequences
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Obesity (cont’d)
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Goals of treatment
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Ideally, treatment would “cure” overweight and obesity
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In reality, this ideal is seldom achieved
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A modest weight loss of 5% to 10% of initial body weight is associated with significant
improvements in blood pressure, cholesterol and plasma lipid levels, and blood glucose
levels
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Obesity (cont’d)
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Goals of treatment (cont’d)
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Modest weight loss:
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Is more attainable
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Is easier to maintain over the long term
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Sets the stage for subsequent weight loss
Obesity (cont’d)
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Evaluating motivation to lose weight
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Objectively identifying who may benefit from weight loss
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Assessing the client’s level of motivation is crucial
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Imposing treatment on an unmotivated or unwilling client may preclude subsequent
attempts at weight loss
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Obesity (cont’d)
Evaluating motivation to lose weight (cont’d)
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Treatment approaches
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A lifestyle approach is the basis of treatment for all people whose BMI is ≥30
 Includes diet modification
 Exercise
 Behavior modification
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Pharmacotherapy and surgery may be used in conjunction with lifestyle
interventions, based on the individual’s BMI and the presence of comorbidities
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Obesity (cont’d)
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Treatment approaches (cont’d)
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Diet modification
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Cornerstone of most weight-loss programs
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Fewer calories
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Macronutrient composition
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Micronutrient composition
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Nutrition education
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Promoting dietary adherence
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Obesity (cont’d)
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Treatment approaches (cont’d)
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Physical activity
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Benefits of exercise are numerous
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Favorably impacts metabolic rate
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Dietary Guidelines recommend adults engage in approximately 60 minutes of
moderate- to vigorous-intensity activity on most days of the week to prevent
weight gain
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Obesity (cont’d)
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Physical activity (cont’d)
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60 to 90 minutes of daily moderate-intensity physical activity are recommended to
sustain weight loss
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Promoting exercise adherence:
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Seems to increase with less structure
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Strategies that may promote exercise adherence
 Exercise at home
 Exercise in multiple short bouts (10 minutes each),
 Adopt a more active lifestyle
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Obesity (cont’d)
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Behavior modification
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Focuses on changing the client’s eating and exercise behaviors
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Key behavior modification strategies:
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Self-monitoring
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Goal setting
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Stimulus control
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Problem solving
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Cognitive restructuring
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Relapse prevention
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Obesity (cont’d)
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Pharmacotherapy
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Recommended for:
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People with a BMI ≥30
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People with a BMI ≥27 with comorbid conditions
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People with waist circumference greater than 35 inches (women) and 40 inches
(men) are also candidates for pharmacotherapy if comorbidities are present
Obesity (cont’d)
Pharmacotherapy (cont’d)
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2 drugs approved by the FDA for long-term use have been shown effective in helping
promote and maintain weight loss
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Alli is the only over-the-counter drug to gain FDA approval for the treatment of
obesity
 Expected weight loss is modest (perhaps half of the usual 6 pounds/1
year credited to orlistat)
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Phentermine
 Approved for short-term use (≤3 months)
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Obesity (cont’d)
Pharmacotherapy (cont’d)
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Drugs are central nervous system stimulants
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Tolerance may develop after only a few weeks
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Risk of abuse
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Common side effects:
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Obesity (cont’d)
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Surgery
Increased heart rate and blood pressure, dry mouth, agitation, insomnia,
nausea, diarrhea, and constipation
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Most effective treatment for severe obesity
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Appropriate for clients whose BMI is 35 to 39.9 who have major comorbidities
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Works by:
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Restricting the stomach’s capacity
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Creating malabsorption of nutrients and calories
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A combination of both
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Obesity (cont’d)
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Surgery (cont’d)
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Laparoscopic adjustable gastric banding (LAGB)
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An inflatable band encircles the uppermost stomach and is buckled
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Small pouch of approximately 15- to 30-mL capacity is created with a limited
outlet between the pouch and the main section of the stomach
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Outlet diameter can be adjusted by inflating or deflating a small bladder inside
the “belt” through a small subcutaneous reservoir
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Obesity (cont’d)
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Laparoscopic adjustable gastric banding (LAGB) (cont’d)
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Size of the outlet can be repeatedly changed as needed
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Mortality rate for gastric banding is the lowest of all bariatric procedures
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Successful weight loss after LAGB requires frequent follow-up and band adjustments
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Obesity (cont’d)
Roux-en-Y gastric bypass (RYBG)
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Combines gastric restriction to limit food intake with the construction of bypasses of the
duodenum and the first portion of the jejunum
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Creates malabsorption of nutrients
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“Dumping syndrome”
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Superior to gastric resection in both promoting and maintaining significant weight loss
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Major complication with RYBG is anastomotic leak
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Obesity (cont’d)
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Post-surgical diet
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Progression begins with small quantities of sugar-free clear liquids
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Advances as tolerated to full liquids, followed by pureed foods and then a regular diet
within 5 to 6 weeks after surgery
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Nutrition therapy guidelines
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Obesity (cont’d)
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Weight maintenance after loss
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Keeping weight off is even harder than losing it
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Diets that lead to weight loss are not necessarily effective for maintaining weight loss
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National Weight Control Registry (NWCR)
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Single best predictor of who will be successful at maintaining weight loss is how long
someone has kept their weight off
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Obesity (cont’d)
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Obesity prevention
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Small changes in diet and exercise that total a mere 100 calories/day may be enough to
prevent obesity in most of the population
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1 ounce of cheddar cheese/day for 1 year = 10 pound weight gain
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Eating Disorders: Anorexia Nervosa (AN), Bulimia Nervosa (BN), and Eating Disorders Not
Otherwise Specified (EDNOS)
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Defined psychiatric illnesses that can have a profound impact on nutritional status and health
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Generally characterized by abnormal eating patterns and distorted perceptions of food and
body weight
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Continuum of disordered eating
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Eating Disorders: Anorexia Nervosa (AN), Bulimia Nervosa (BN), and Eating Disorders Not
Otherwise Specified (EDNOS) (cont’d)
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Etiology
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Considered to be multifactorial in origin
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Risk factors:
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Dieting, early childhood eating and GI problems, increased concern about
weight and size, negative self-evaluation, and sexual abuse
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Eating Disorders: Anorexia Nervosa (AN), Bulimia Nervosa (BN), and Eating Disorders Not
Otherwise Specified (EDNOS) (cont’d)
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Etiology (cont’d)
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Precipitating factors
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Onset of puberty, parents’ divorce, death of a family member, and ridicule of
being or becoming fat
People with eating disorders often suffer from:
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Depression, anxiety, substance abuse, or body dysmorphic disorder
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Eating Disorders: Anorexia Nervosa (AN), Bulimia Nervosa (BN), and Eating Disorders Not
Otherwise Specified (EDNOS) (cont’d)
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Etiology (cont’d)
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Treatment plans are highly individualized
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Antidepressant drugs effectively reduce the frequency of problematic eating behaviors
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Most eating disorders are treated on an outpatient basis
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Nutritional intervention seeks to reestablish and maintain normal eating behaviors
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Nutrition Therapy for Anorexia
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Step-by-step goals of nutrition therapy:
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To prevent further weight loss
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To gradually reestablish normal eating behaviors
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To gradually increase weight
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To maintain agreed-upon weight goal
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Half of those who receive care are expected to recover
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Overall mortality rate is 9.8%
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Nutrition Therapy for Anorexia (cont’d)
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Involving the client in formulating individualized goals and plans promotes compliance
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Large amounts of food may not be well tolerated
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Nutrition Therapy for Bulimia Nervosa
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People with BN tend to have fewer serious medical complications than people with AN because
their undernutrition is less severe
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Nutritional counseling focuses on identifying and correcting food misinformation and fears
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Structured and relatively inflexible to promote the client’s sense of control
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Initial meal plan provides adequate calories for weight maintenance
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Nutrition Therapy for Bulimia Nervosa (cont’d)
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Adequate fat is provided to help delay gastric emptying and contribute to satiety
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Calories are gradually increased as needed
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Eating Disorders Not Otherwise Specified
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At least as common as AN and BN
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This group represents:
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Subacute cases of AN or BN
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Binge eating disorder