45
Obesity
Mariann M. Harding
http://evolve.elsevier.com/Lewis/medsurg/
CONCEPTUAL FOCUS
Functional Ability Nutrition
Health Promotion Self-Management
LEARNING OUTCOMES
1. Discuss the epidemiology and etiology of obesity. 6. Describe the nursing and interprofessional management
2. Explain the health risks associated with obesity. related to surgical therapies for obesity.
3. Use classification systems to determine body size. 7. Describe the etiology, clinical manifestations, and nursing
4. Discuss comprehensive therapy for the patient with obesity. and interprofessional management of metabolic syndrome.
5. Distinguish among the bariatric surgical procedures used to
treat obesity.
KEY TERMS
bariatric surgery obese
body mass index (BMI) obesity
extreme obesity overweight
lipectomy waist-to-hip ratio (WHR)
metabolic syndrome
Midwest (Fig. 45.2), among Blacks and Hispanics (Fig. 45.3,
OBESITY Box 45.1), and among lower-income, less-educated Americans.1
Obesity is an excessively high amount of body fat or adipose tissue. Obesity in adulthood is often a problem that begins in child-
Obesity is a global problem because it is a major risk factor for lead- hood or adolescence. More than 1 in 10 children becomes obese
ing causes of death, including type 2 diabetes, heart disease, and cer- as early as age 2 to 5.1 Reversing the childhood obesity crisis is a
tain cancers. Those who are overweight often have other problems, key part of addressing the obesity epidemic.
such as problems with mobility and sleeping, that affect health.
The consequences of obesity extend beyond the physical Etiology and Pathophysiology
changes. Social stigma can take an emotional toll on a person’s Obesity is a complex, multifactorial disease. It is the result of
psychologic well-being. Many struggle with altered body image, an energy imbalance where one takes in more calories than
depression, and low self-esteem and withdraw from social inter- one needs for the body’s physical and metabolic functions. This
action. Attitudes about obesity can create biases and discrimi- results in an abnormal increase and accumulation of fat cells.
nation against people who are obese. Obesity should be viewed Many factors, including genetic and environmental influences,
and treated as a chronic disease, just like other chronic diseases, can contribute to obesity. Personal decisions about food choices,
such as diabetes and hypertension. portion sizes, and exercise also are factors.
In obesity, there is an increase in the number of adipocytes,
Epidemiology of Obesity or fat cells, and an increase in their size (hypertrophy). Adipocyte
Obesity is a major public health issue in the United States (Fig. hypertrophy is a process by which fat cells can increase their vol-
45.1). Currently, about 43% of adults in the United States are ume several thousand times to accommodate large increases
obese. Significant geographic, racial and ethnic, and income in lipid storage. When storage of existing fat cells is exceeded,
disparities exist. Obesity rates are highest in the South and preadipocytes are triggered to become adipocytes. This process
1030
, CHAPTER 45 Obesity 1031
occurs mainly in the visceral (intraabdominal) and subcuta- Genetic Link
neous tissues. The greatest increase in the number of fat cells We have linked over 400 genes to obesity. Having one or more
occurs from infancy through adolescence. of these genes means the person is more predisposed to obesity
Most obese persons have primary obesity, which is excess than people without these genes, but it does not mean that they
calorie intake over energy expenditure for the body’s metabolic will become obese. Genes contribute to obesity in many ways.
demands. Others have secondary obesity, in which a medical They affect appetite, satiety (the sense of fullness), food crav-
problem caused the weight gain. These problems include some ings, body-fat distribution, and how we store calories. Having
congenital conditions, endocrine disorders, central nervous a family history of obesity increases a person’s chance of devel-
system (CNS) lesions and disorders, or drugs (e.g., corticoste- oping obesity.2
roids, antipsychotics). Several rare forms of obesity result from mutations in a
single gene. Obesity is also part of several genetic syndromes
caused by mutation or chromosomal abnormalities, such as
Prader–Willi syndrome.2 The best link is with a gene known as
FTO (fat mass and obesity-associated gene). People with a cer-
tain allele of the FTO gene appear to have an increased appetite
and reduced satiety, with a higher calorie intake.
Physiologic Regulatory Mechanisms in Obesity
Knowing how appetite is triggered and energy is spent is
important for understanding obesity and specific targets
for drug therapy. The hypothalamus, gut, and adipose tissue
synthesize hormones and peptides that stimulate or inhibit
appetite (Fig. 45.4). The hypothalamus is a major site for
regulating appetite. Neuropeptide Y, made in the hypothala-
mus, is a powerful appetite stimulant. When it is imbalanced,
it leads to overeating and obesity. Hormones and peptides
Fig. 45.1 The obesity epidemic has taken its toll on both adults and made in the gut and adipocyte cells affect the hypothala-
children in the United States. (© iStock.com/IPGGutenbergUKLtd.) mus and have a critical role in appetite and energy balance
WA ME
MT ND VT
MN NH
OR NY
ID WI MA
SD MI CT RI
WY PA
IA DC
NE OH MD DE
NV IL IN WV
UT VA
CO
KS MO KY
CA
NC
TN
OK SC
AZ AR
NM
MS AL GA
20%–<25%
TX 25%–<30%
LA
30%–<35%
FL ≥35%
Insufficient data*
AK
HI GU PR
Fig. 45.2 Prevalence of obesity among US adults by state and territory. (Source: Behavioral Risk Factor Sur-
veillance System. Retrieved from https://www.cdc.gov/obesity/data/prevalence-maps.html.)
, 1032 SECTION 9 Problems of Ingestion, Digestion, Absorption, and Elimination
Non-Hispanic White Non-Hispanic Black Non-Hispanic Asian Hispanic
60
56.9
49.6
44.8 45.7
44.7 43.7
42.2 41.1
39.8
40
Percent
20 17.4 17.5 17.2
0
Total Men Women
Fig. 45.3 Obesity affects some groups disproportionately. Among US adults, Black and Hispanic populations
have the highest rates of obesity. (Source: Centers for Disease Control and Prevention: Prevalence of obe-
sity and severe obesity among adults: US, 2017–2018. Retrieved from https://www.cdc.gov/nchs/products/
databriefs/db360.htm.)
BOX 45.1 PROMOTING HEALTH dysfunction, which leads to insulin resistance, dyslipidemia,
EQUITY and high blood pressure.4 This causes people with abdominal
(android) obesity more complications of obesity.
Obesity
• H ispanics (44.8%) and Blacks (49.6%) have the highest rates of obesity. Environmental Factors
• Among women, Blacks (56.9%) have the highest prevalence of being obese. Environmental factors play a key role in obesity. In today’s cul-
• Among men, Hispanics (45.7%) have the highest prevalence of being ture, people have greater access to high-calorie, energy-dense
obese. food and highly sweetened drinks. Eating outside of the home
• Asian Americans have the lowest prevalence of being obese. lends to obesity because one eats higher calorie foods with large
portion sizes. Portion size has increased dramatically (Fig.
45.5). Lack of physical exercise is another factor that contributes
(Table 45.1). When overeating develops at an early age and to weight gain and obesity. We expend less energy in our every-
continues into adulthood, it alters one’s ability to sense full- day lives due to economic growth, technology use, and social
ness (satiety). changes. Increased time spent gaming, surfing the Internet, and
Leptin is made in the adipocyte. It acts in the hypothalamus watching TV contribute to the increase in sedentary habits.
to suppress appetite and increase fat metabolism. A genetic defi- Socioeconomic status is a known risk factor for obesity in
ciency of leptin causes extreme obesity. However, most obese several ways.5 There may be a lack of access to affordable and
persons have high leptin levels, suggesting they are leptin resis- nutritious food at full-service grocers and farmer’s markets.
tant.3 This may be due to a failure to make enough leptin recep- People with low incomes stretch their limited food dollars by
tors or producing faulty receptors. buying less expensive foods that often have poor nutritional
Ghrelin, a gut hormone, regulates appetite by inhibiting quality with greater caloric content. Low-income neighbor-
leptin. It acts in the hypothalamus and the brain’s pleasure cen- hoods often lack locations for healthy exercise, such as parks,
ters to stimulate hunger. In a non-obese person, ghrelin levels playgrounds, walking trails, and swimming pools.
are higher when a person is hungry and decrease after eating.
Gastric bypass patients do not have the premeal increase in Psychosocial Factors
ghrelin.2 The low ghrelin levels help suppress appetite and con- People use food for many reasons besides nutrition. Associations
tribute to the surgery’s effectiveness. with food begin in childhood, such as the use of food for com-
Adipocytes make substances we call adipokines. Adipokines fort or rewards. The social component of eating begins early
play roles in glucose and lipid metabolism, insulin sensitiv- in life when food is associated with pleasure and fun at such
ity, energy homeostasis, inflammation, immunity, and vascu- events as birthday parties and holidays. Stress, sadness, anxi-
lar function. Excess visceral fat is associated with adipokine ety, and other emotions can lead people to eat too much. Eating
Obesity
Mariann M. Harding
http://evolve.elsevier.com/Lewis/medsurg/
CONCEPTUAL FOCUS
Functional Ability Nutrition
Health Promotion Self-Management
LEARNING OUTCOMES
1. Discuss the epidemiology and etiology of obesity. 6. Describe the nursing and interprofessional management
2. Explain the health risks associated with obesity. related to surgical therapies for obesity.
3. Use classification systems to determine body size. 7. Describe the etiology, clinical manifestations, and nursing
4. Discuss comprehensive therapy for the patient with obesity. and interprofessional management of metabolic syndrome.
5. Distinguish among the bariatric surgical procedures used to
treat obesity.
KEY TERMS
bariatric surgery obese
body mass index (BMI) obesity
extreme obesity overweight
lipectomy waist-to-hip ratio (WHR)
metabolic syndrome
Midwest (Fig. 45.2), among Blacks and Hispanics (Fig. 45.3,
OBESITY Box 45.1), and among lower-income, less-educated Americans.1
Obesity is an excessively high amount of body fat or adipose tissue. Obesity in adulthood is often a problem that begins in child-
Obesity is a global problem because it is a major risk factor for lead- hood or adolescence. More than 1 in 10 children becomes obese
ing causes of death, including type 2 diabetes, heart disease, and cer- as early as age 2 to 5.1 Reversing the childhood obesity crisis is a
tain cancers. Those who are overweight often have other problems, key part of addressing the obesity epidemic.
such as problems with mobility and sleeping, that affect health.
The consequences of obesity extend beyond the physical Etiology and Pathophysiology
changes. Social stigma can take an emotional toll on a person’s Obesity is a complex, multifactorial disease. It is the result of
psychologic well-being. Many struggle with altered body image, an energy imbalance where one takes in more calories than
depression, and low self-esteem and withdraw from social inter- one needs for the body’s physical and metabolic functions. This
action. Attitudes about obesity can create biases and discrimi- results in an abnormal increase and accumulation of fat cells.
nation against people who are obese. Obesity should be viewed Many factors, including genetic and environmental influences,
and treated as a chronic disease, just like other chronic diseases, can contribute to obesity. Personal decisions about food choices,
such as diabetes and hypertension. portion sizes, and exercise also are factors.
In obesity, there is an increase in the number of adipocytes,
Epidemiology of Obesity or fat cells, and an increase in their size (hypertrophy). Adipocyte
Obesity is a major public health issue in the United States (Fig. hypertrophy is a process by which fat cells can increase their vol-
45.1). Currently, about 43% of adults in the United States are ume several thousand times to accommodate large increases
obese. Significant geographic, racial and ethnic, and income in lipid storage. When storage of existing fat cells is exceeded,
disparities exist. Obesity rates are highest in the South and preadipocytes are triggered to become adipocytes. This process
1030
, CHAPTER 45 Obesity 1031
occurs mainly in the visceral (intraabdominal) and subcuta- Genetic Link
neous tissues. The greatest increase in the number of fat cells We have linked over 400 genes to obesity. Having one or more
occurs from infancy through adolescence. of these genes means the person is more predisposed to obesity
Most obese persons have primary obesity, which is excess than people without these genes, but it does not mean that they
calorie intake over energy expenditure for the body’s metabolic will become obese. Genes contribute to obesity in many ways.
demands. Others have secondary obesity, in which a medical They affect appetite, satiety (the sense of fullness), food crav-
problem caused the weight gain. These problems include some ings, body-fat distribution, and how we store calories. Having
congenital conditions, endocrine disorders, central nervous a family history of obesity increases a person’s chance of devel-
system (CNS) lesions and disorders, or drugs (e.g., corticoste- oping obesity.2
roids, antipsychotics). Several rare forms of obesity result from mutations in a
single gene. Obesity is also part of several genetic syndromes
caused by mutation or chromosomal abnormalities, such as
Prader–Willi syndrome.2 The best link is with a gene known as
FTO (fat mass and obesity-associated gene). People with a cer-
tain allele of the FTO gene appear to have an increased appetite
and reduced satiety, with a higher calorie intake.
Physiologic Regulatory Mechanisms in Obesity
Knowing how appetite is triggered and energy is spent is
important for understanding obesity and specific targets
for drug therapy. The hypothalamus, gut, and adipose tissue
synthesize hormones and peptides that stimulate or inhibit
appetite (Fig. 45.4). The hypothalamus is a major site for
regulating appetite. Neuropeptide Y, made in the hypothala-
mus, is a powerful appetite stimulant. When it is imbalanced,
it leads to overeating and obesity. Hormones and peptides
Fig. 45.1 The obesity epidemic has taken its toll on both adults and made in the gut and adipocyte cells affect the hypothala-
children in the United States. (© iStock.com/IPGGutenbergUKLtd.) mus and have a critical role in appetite and energy balance
WA ME
MT ND VT
MN NH
OR NY
ID WI MA
SD MI CT RI
WY PA
IA DC
NE OH MD DE
NV IL IN WV
UT VA
CO
KS MO KY
CA
NC
TN
OK SC
AZ AR
NM
MS AL GA
20%–<25%
TX 25%–<30%
LA
30%–<35%
FL ≥35%
Insufficient data*
AK
HI GU PR
Fig. 45.2 Prevalence of obesity among US adults by state and territory. (Source: Behavioral Risk Factor Sur-
veillance System. Retrieved from https://www.cdc.gov/obesity/data/prevalence-maps.html.)
, 1032 SECTION 9 Problems of Ingestion, Digestion, Absorption, and Elimination
Non-Hispanic White Non-Hispanic Black Non-Hispanic Asian Hispanic
60
56.9
49.6
44.8 45.7
44.7 43.7
42.2 41.1
39.8
40
Percent
20 17.4 17.5 17.2
0
Total Men Women
Fig. 45.3 Obesity affects some groups disproportionately. Among US adults, Black and Hispanic populations
have the highest rates of obesity. (Source: Centers for Disease Control and Prevention: Prevalence of obe-
sity and severe obesity among adults: US, 2017–2018. Retrieved from https://www.cdc.gov/nchs/products/
databriefs/db360.htm.)
BOX 45.1 PROMOTING HEALTH dysfunction, which leads to insulin resistance, dyslipidemia,
EQUITY and high blood pressure.4 This causes people with abdominal
(android) obesity more complications of obesity.
Obesity
• H ispanics (44.8%) and Blacks (49.6%) have the highest rates of obesity. Environmental Factors
• Among women, Blacks (56.9%) have the highest prevalence of being obese. Environmental factors play a key role in obesity. In today’s cul-
• Among men, Hispanics (45.7%) have the highest prevalence of being ture, people have greater access to high-calorie, energy-dense
obese. food and highly sweetened drinks. Eating outside of the home
• Asian Americans have the lowest prevalence of being obese. lends to obesity because one eats higher calorie foods with large
portion sizes. Portion size has increased dramatically (Fig.
45.5). Lack of physical exercise is another factor that contributes
(Table 45.1). When overeating develops at an early age and to weight gain and obesity. We expend less energy in our every-
continues into adulthood, it alters one’s ability to sense full- day lives due to economic growth, technology use, and social
ness (satiety). changes. Increased time spent gaming, surfing the Internet, and
Leptin is made in the adipocyte. It acts in the hypothalamus watching TV contribute to the increase in sedentary habits.
to suppress appetite and increase fat metabolism. A genetic defi- Socioeconomic status is a known risk factor for obesity in
ciency of leptin causes extreme obesity. However, most obese several ways.5 There may be a lack of access to affordable and
persons have high leptin levels, suggesting they are leptin resis- nutritious food at full-service grocers and farmer’s markets.
tant.3 This may be due to a failure to make enough leptin recep- People with low incomes stretch their limited food dollars by
tors or producing faulty receptors. buying less expensive foods that often have poor nutritional
Ghrelin, a gut hormone, regulates appetite by inhibiting quality with greater caloric content. Low-income neighbor-
leptin. It acts in the hypothalamus and the brain’s pleasure cen- hoods often lack locations for healthy exercise, such as parks,
ters to stimulate hunger. In a non-obese person, ghrelin levels playgrounds, walking trails, and swimming pools.
are higher when a person is hungry and decrease after eating.
Gastric bypass patients do not have the premeal increase in Psychosocial Factors
ghrelin.2 The low ghrelin levels help suppress appetite and con- People use food for many reasons besides nutrition. Associations
tribute to the surgery’s effectiveness. with food begin in childhood, such as the use of food for com-
Adipocytes make substances we call adipokines. Adipokines fort or rewards. The social component of eating begins early
play roles in glucose and lipid metabolism, insulin sensitiv- in life when food is associated with pleasure and fun at such
ity, energy homeostasis, inflammation, immunity, and vascu- events as birthday parties and holidays. Stress, sadness, anxi-
lar function. Excess visceral fat is associated with adipokine ety, and other emotions can lead people to eat too much. Eating
