Handbook of Psychology

CHAPTER 6

Obesity

JOYCE A. CORSICA AND MICHAEL G. PERRI

121

CLASSIFICATION OF OBESITY 121
“Ideal Weight” 122
Body Mass Index 122
The WHO Classification System 122
Measurement of Abdominal Fat 123
EPIDEMIOLOGY OF OBESITY 123
CONSEQUENCES OF OBESITY 124
Impact on Morbidity 124
Impact on Mortality 125
Psychosocial Consequences 125
Economic Costs of Obesity 125
CONTRIBUTORS TO OBESITY 126
Genetic Contributors 126
Environmental Contributors 126
TREATMENT OF OBESITY 128
Lifestyle Interventions 128
Pharmacotherapy 129
Bariatric Surgery 130
STRATEGIES TO IMPROVE LONG-TERM OUTCOME 131
Very Low-Calorie Diets 131
Extended Treatment 132

Relapse Prevention Training 133

Telephone Prompts 133

Food Provision/Monetary Incentives 133

Peer Support 133

Exercise/Physical Activity 134

Multicomponent Posttreatment Programs 135

Summary 135

FUTURE RESEARCH DIRECTIONS 135

Address Unrealistic Weight-Loss Expectations 135

Match Treatments to Clients 136

Test Innovative Models 136

Examine Schedules of Follow-Up Care 136

IMPROVING THE MANAGEMENT AND PREVENTION

OF OBESITY 136

Managing Obesity 136

Prevention of Obesity 137

CONCLUSION 138

REFERENCES 138

Over the past two decades, the prevalence of overweight and
obesity in the United States has increased dramatically
(Flegal, Carroll, Kuczmarski, & Johnson, 1998). More than
half of all Americans are now overweight or obese (Mokdad
et al., 1999), and the trend toward increasing prevalence
has not abated (Mokdad et al., 2000). Concern about this
epidemiclike trend stems from an overwhelming body of
evidence demonstrating the negative health consequences
associated with increased body weight. Being overweight or
obese substantially raises the risk for a variety of illnesses,
and excess weight is associated with increased all-cause
mortality (Pi-Sunyer, 1999). Consequently, millions of
Americans stand poised to develop weight-related illnesses
such as cardiovascular disease, hypertension, diabetes melli-
tus, and osteoarthritis. As the second leading contributor to
preventable death in the United States (McGinnis & Foege,
1993), obesity constitutes a major threat to public health and
a signi“cant challenge to health care professionals.

In this chapter, we provide a review of research related to

understanding and managing obesity. We begin with the as-

sessment and classi“cation of obesity, and we describe the epi-

demiology of body weight in the United States. We summarize

the physical, psychosocial, and economic consequences asso-

ciated with excess body weight, and we examine prominent

biological and environmental contributors to obesity. Next

we describe current treatments of obesity, including behav-

ioral (lifestyle) interventions, pharmacotherapy, and bariatric

surgery; we give special attention to what may be the most

problematic aspect of obesity treatment, the maintenance of

lost weight. We conclude our review by discussing recom-

mendations for the management and prevention of obesity.

CLASSIFICATION OF OBESITY

Obesity is de“ned as an excessive accumulation of body

fat„excessive to the extent that it is associated with negative