Lecture
Outline
Chapter 10
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Energy Balance and
Weight Control
Chapter 10
Insert photo from 1st page of
chapter
Chapter Learning Outcomes
1.
Describe the uses of energy by the body and
explain the concept of energy balance.
2.
Identify factors that influence body weight.
3.
Discuss how BMI is used to determine whether a
person’s weight is healthy.
4.
Describe ways to measure body composition.
5.
List major health risks associated with excess body
fat.
Chapter Learning Outcomes
(continued)
6. Plan a long-term weight-loss regimen that
is safe and effective.
7. Evaluate popular weight-reduction diets
for safety and long-term effectiveness.
8. Identify surgical procedures for severe
obesity.
9. Describe treatments for underweight.
10. Identify major eating disorders, and
discuss risk factors and treatments for
these conditions.
Quiz Yourself
True or False
1.
2.
3.

You can determine whether you have an unhealthy
amount of body fat simply by measuring your
waistline. T F
The best way to lose weight and keep it off is to
follow a fad diet, such as the Atkins diet. T F
As people age, their muscle cells turn into fat cells.
T F
4.
5.
When a person consumes more carbohydrate than
needed, the excess is converted to fat and stored in
fat cells. T F
Cellulite is a unique type of fat that can be
eliminated by taking certain dietary supplements.
T F
Quiz Yourself
True or False

1. True You can determine whether you have
an unhealthy amount of body fat simply by
measuring your waistline.
2. False No fad diet is the “best way” to lose
weight and keep it off.
3. False As people age, their muscle cells do
not turn into fat cells.
4. True Excess carbohydrate is converted to
fat and stored in fat cells.
5. False Cellulite is not a unique type of fat.
What are Overweight and Obesity?
• Overweight and obesity are conditions
characterized by excessive body fat.
– Most common nutritional disorders in the U.S.
• In 2003-2004:
– 2/3 of American adults were either overweight
or obese.
• 1/3 of American adults were obese.
• The prevalence of excess body fat among infants
and children is also increasing.
• Obesity is difficult to treat
More than half of all American adults
tried to lose or maintain weight in 20012002.
Preventing obesity
is the key.
Body Composition
Two major components:
– Fat-free mass
• Body water, mineral-rich tissues, and proteinrich tissues
– Total body fat
• Adipose tissue
• Essential fat in cell membranes, certain bones,
and nervous tissue
Adipose Tissue
• All cells contain some
lipids, but adipose cells
store a droplet of fat.
– Overeating can cause
increase in fat cell size and
number.
• Scientists think that once
fat cells are formed, they
remain, unless they die or
are surgically removed.
Insert Figure 6.15
Subcutaneous Fat Distribution
• Insert figure 10.1
What is Brown Fat?
• Brown fat
– Contains more mitochondria
and blood supply
– Functions to generate heat
– Found in upper back and
abdomen of infants
• White fat
– Is white in appearance
– Functions to store fat
Insert Figure 10.2
Underwater Weighing
• Compares weight on
land to weight when
completely submerged
in a tank of water
• Problems:
– inconvenient,
expensive, and
impractical
• Insert figure 10.3
Dual-Energy X-Ray
Absorptiometry (DXA)
• Uses multiple lowenergy X-rays to scan
the body
• Provides detailed
“picture” of internal
structures
• Problems:
– Very expensive and not
widely available outside
of clinical settings
Bioelectrical Impedance
• Measures conduction of
a weak electrical
current through the
body
• Problem:
– Method can be reliable if
body hydration status is
normal.
• Scientific data about the
accuracy of bioelectrical
impedance devices for
home use are lacking.
• Insert figure 10.5
Skinfold Thickness
• Skinfold thickness is
measured at multiple body
sites by trained person.
• Benefits:
– Relatively easy and
inexpensive to perform
• Problems:
– May underestimate total body
fat on overfat people
How Much Body Fat Is Too
Much?
• Insert Table
10.1
Using BMI to Classify Body
Weight
• What is BMI?
– Numerical value of relationship between
body weight and risk of certain chronic
health problems
• Simple formula:
Weight (lbs)
 Height (in)2 X 703
Adult Weight Status
Categories (BMI)
• Insert table
10.2
Health Problems Associated
with Excess Body Fat
• Insert table 10.3
Body Fat Distribution
Distribution of excess body fat is more
closely associated with obesity-related
diseases than the percentage of total
body fat.
• Heart disease, type 2 diabetes, hypertension
Upper body obesity is characterized by
excessive abdominal (visceral) fat.
Lower Body Fat Distribution
• Lower body fat or
“pear shape” adds
stress to hip and
knee joints, but
carries lower risk
of chronic
diseases such as
type 2 diabetes.
• Insert figure 10.7
Upper Body Fat Distribution
Excess upper body fat or
“apple shape” poses
higher risk of serious
health problems.
• May result in the release
of fatty acids that
negatively affect the liver
• May be source of
inflammation
• Insert figure
10.7
Measuring Waist Circumference
• Insert
figure
10.8
• Waist circumference is a
quick and easy way to
determine obesity-related
risk.
Desirable circumferences:
• Men < 40 in.
• Women < 35 in.
Energy for Living
What is Energy?
– The capacity to perform work
• Forms of energy in living things:
– Heat, mechanical, chemical, and electrical
• Amount of energy is constant
– Energy can be stored, released, moved, or
transformed from one form of energy to
another.
Energy Intake
“Biological fuels” are macronutrients
in foods and beverages
– Glucose and fatty acids are the main
fuels.
• Small amounts of amino acids are also
metabolized for energy.
Energy is captured in the molecule ATP.
What Happens to Macronutrients?
• Insert figure 10.9
Energy Output
Energy output or expenditure: energy cells use
to carry out activities
• Basal and resting metabolism
• Physical activity
• Thermic effect of food (TEF)
• Nonexercise activity thermogenesis
(NEAT)
Basal and Resting Metabolism
Metabolism– Sum of all chemical changes or reactions
that constantly occur in living cells
• Anabolic reactions require energy
• Catabolic reactions release energy
Basal metabolism
– Minimal number of calories the body uses for vital
physiological activities after fasting and resting for
12 hours
Factors that Influence
Metabolic Rate
Factors that influence metabolic rate include:
–
–
–
–
–
–
–
–
–
–
Thyroid hormone levels
Body composition
Gender
Age
Body surface area
Calorie intake
Fever
Stimulant drugs
Pregnancy and lactation
Recovery after exercise
Calculating Metabolic
Energy Needs
“Rule of Thumb Formulas”
For men: 1.0 kcal/kg/hr
For women: 0.9 kcal/kg/hr
Energy for Physical Activity
• Physical activity increases energy
needs above basal energy needs.
• Caloric expenditure is dependent on:
• Type of activity
• Duration
• Intensity
• Weight of the person
Approximate
Energy
Expenditure of
Selected
Physical
Activities
• Insert table 10.4
Two Other Uses of Energy
Thermic Effect of Food (TEF)
• Energy used to digest foods and beverages, and
absorb and process the nutrients
• Typically 5 to 10% of total caloric intake
Nonexercise Activity Thermogenesis (NEAT)
• Energy spent on involuntary skeletal muscle activity
such as fidgeting, shivering, and maintaining muscle
tone or body posture
• May account for an additional 100 to 800 kcal/d
Putting It All Together
To estimate daily energy needs, add together
energy (kcal) used for:
Basal Metabolism
Physical Activity
Thermic Effect of Food (TEF)
Nonexercise Activity Thermogenesis
(NEAT)
Energy Balance
• Insert Figure 10.10
Body Energy States
Insert figure10.11
Factors that Contribute to
Obesity
• Physiological aspects
• Environmental influences
• Socioeconomic status
• Psychological conditions
Physiological Factors
Hunger vs. satiety
Orexins — peptides (secreted by
hypothalamus) that may contribute
to hunger
Ghrelin — hormone (secreted
mainly by stomach) that stimulates
eating behavior
Leptin — hormone (secreted by
adipose cells) that reduces hunger
and inhibits fat storage in the body
Insert figure 10.12
Genetic Factors
• Inherited characteristics that influence
weight include:
– Metabolic rate
• “thrifty metabolism”
– Hormone production
– Body frame size
– Pattern of fat distribution
What is the set-point theory?
• Scientific notion that body fat content is genetically
predetermined
Environmental Influences
Appetite
– the desire to eat appealing foods
Environmental influences include:
• Food advertising
• Increased portion sizes
• Conditions that reduce a person’s
physical activity
Other Factors that Influence
Weight
•
•
•
•
•
•
Income
Education
Self-esteem
Mood
Boredom
Societal pressure
• Insert photo
of skinny legs
from page
346
Features of
Reliable
WeightLoss Plans
• Insert
table
10.7
Four Key Factors of Successful
Long-Term Weight Management
1. Motivation
2. Calorie reduction
3. Regular physical
activity
4. Behavior modification
Motivation
Motivating factors include:
– Recognition of need to change
– Weight loss “triggers”
– Medical recommendation to lose weight
Commitment to lose weight and enjoy better
health must be more important than desire to
overeat.
Calorie Reduction
• Loss of 1 lb body fat requires a
negative energy state of 3500 kcal
• To lose 1 lb in 7 days:
– Consume 500 kcal less per day
– Expend 500 kcal more per day
– Or combine eating less and exercising more to result in
a deficit of 3500 kcal
Ideal dietary pattern: reduced intake of foods and
beverages that contain high amounts of added
sugars, fats, and/or alcohol
Behavior Modification
• Analyze behaviors to identify cues and
problem behaviors.
– “Cues” are environmental factors that
stimulate eating behavior, such as viewing
food commercials.
• Develop ways to change problem foodrelated or physical activity-related
behaviors.
Community-Based WeightLoss Programs
Answer the following questions before joining:
– What is the cost? If a contract is signed, what is
length of contract?
– Are special foods required?
– If nutrition counseling is provided, does the counselor
have appropriate nutrition/dietetics training?
– Does program emphasize lifestyle changes?
– Does the program’s advertising include questionable
weight-loss claims and deceptive testimonials?
Successful Dieters—How Do
They Manage Their Weight?
• Based on the National Weight Control
Registry, successful dieters do the following:
– Eat low-calorie, low-fat, high-carbohydrate diets
(~1800 kcal and 25% kcal from fat)
– Maintain same diet regimen every day
– Eat regular meals, including breakfast
– Weigh themselves at least once each week
– Exercise at least 60 min/d to burn ~400 kcal
– Eat a limited variety of foods
Medical Treatment for Obesity
Weight-Loss Medications
Sibutramine (Meridia)
• Action: alters brain chemistry, delaying hunger
• Side effects: constipation, dry mouth, sleep
disturbances, and increased blood pressure
Orlistat (Xenical and Alli)
• Action: reduces fat digestion by ~30%
• Side effects: oily unpleasant feces and
reduction in fat-soluble vitamin absorption
Bariatric Surgical Procedures
• Bariatric surgery is effective method of treating
extreme obesity.
– Surgery reduces size of stomach, limiting the
amount of food that can be eaten.
• After weight loss, patients often achieve normal
blood pressure, glucose, and triglyceride levels
• Complications include: intestinal blockage and
bleeding, ulcer or blood clot formation.
– Death due to complications results in 1% of
patients.
Roux-en-Y Gastric Bypass
• Procedure reduces stomach capacity to ~ 1.5 oz
• Small intestine is cut with lower end attached to the
newly formed stomach pouch
• Insert figure
10.15
Gastric Bypass with Stapling
Some patients have a more drastic gastric bypass
procedure.
• Insert figure
10.15
Adjustable Gastric Banding
• A small stomach pouch is created with an adjustable band
instead of fixed surgical staples.
• Tightness of the band determines the size of the stomach.
• Insert figure 10.16
What Is Liposuction?
• Surgical method of
suctioning the excess fat
out of the body
– cosmetic procedure to
improve body contours
– Not considered a
treatment for obesity
• Insert figure 10.17
Fad Diets
• Insert table 10.8
Characteristics of
A Typical Fad Weight Loss Diet
 Offers a “quick fix” with rapid weight loss
 Limits food selections to a few food groups
 Requires buying a book or various gimmicks,
such as supplements, patches, or creams
 Uses outlandish and unscientific claims
 Relies on testimonials of famous people
 Does not emphasize the need to change
eating habits and physical activity patterns
Low Carbohydrate Approaches
• Examples of low carbohydrate diets: Atkin's,
Scarsdale, and Four-Day Wonder Diet
• Initial rapid weight loss is linked to water
loss.
• Results of studies indicate that after 6
months, people on low-carb diets lost more
weight than people on low-fat diets.
• But after 1 year, there was no
difference in weight loss between the
two diet plans.
Very-Low-Fat Approaches
• Diet limits fat to 5 to 10% of total
calories
• Results in rapid weight loss if followed
consistently
• Examples are the Pritikin Diet and
Ornish’s “Eat More, Weigh Less” diet
• Very-low-fat diets are not harmful for
healthy adults, but adherence is very low.
Dietary Supplements for
Weight Loss
Gaining Weight
• Factors contributing to
underweight:
– Genetics, lifestyle practices,
chronic diseases,
psychological disturbances,
cancer, TB, or AIDS
• To gain weight:
– Add high-calorie healthy
foods, such as low-fat
cheeses, olives, avocados,
seeds, nuts, or granola, to
diet.
• Insert photo of
skinny man
from page 361
Chapter 10 Highlight
Over the Deep Edge
Disordered Eating or Eating Disorder?
• Disordered Eating
– Excessive concern about body size and social
pressure to avoid weight gain
• Eating Disorders
– Diagnosed when disordered eating behaviors
become a lifestyle
– Psychological disturbances that lead to certain
physiological changes and serious health
complications
Anorexia Nervosa
• Definition
– Severe psychological disturbance characterized
by self-imposed starvation resulting in
malnutrition and low body weight
• Prevalence
– ~90% of cases are females
– Affects 1 in 200 women
Anorexia Nervosa (continued)
People with anorexia nervosa:
• Maintain BMI of 17.5 or less
• Have distorted body images
• Are obsessed with losing weight
• Avoid “fattening foods”
• Engage in one or more of the following:
– Self-induced vomiting
– Abuse of laxatives
– Excessive exercise
– Use of appetite suppressants
• Display signs of hormonal imbalances
• Are depressed or anxious
Bulimia Nervosa
• Definition
– Eating disorder characterized by cyclic
episodes of bingeing and calorie-restrictive
dieting
– People typically binge on cakes, cookies, ice
cream, and other high-fat, high-carbohydrate
foods.
• Prevalence
– Affects 2 to 5% of U.S. population
– More common in females
Bulimia Nervosa
(continued)
• Characteristics include:
– Scrapes or scars on knuckles
– Blood chemistry abnormalities, particularly
low potassium levels
– Swollen salivary glands
– Tears or bleeding of the esophagus
Bulimia Nervosa
(continued)
• Treatment
– A team approach similar to that used
with anorexia nervosa
– May require use of antidepressants
• Prognosis
– Up to 60% of cases improve with
treatment
Binge-Eating Disorder
Night Eating Syndrome
• Both characterized by food binges NOT followed by
purging
– More common in overfat people
• Binge-Eating Disorder
– ~1 to 2% of Americans suffer from binge-eating
– During binge, person eats large amounts of energy-dense
foods, such as ice cream, chips, and cookies, in secret.
• Night Eating Syndrome
– Person is not hungry during the morning, but wakes up and
eats during the night.
Female Athlete Triad
• Characterized by disordered eating, lack of
menstrual periods, and osteoporosis
– Common in appearance-based competitive
sports, such as gymnastics, swimming, and
distance running
• Seen in 15 to 60% of female athletes
• Treatment goal: improving the patient’s nutritional
state to reverse the signs and symptoms