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131
Chapter 8 – Energy Balance and Body Composition
Learning Objectives
After completing Chapter 8, the student will be able to:
8.1 Describe energy balance and the consequences of not being in balance.
8.2 Discuss some of the physical, emotional, and environmental influences on food intake.
8.3 List the components of energy expenditure and factors that might influence each.
8.4 Distinguish between body weight and body composition, including methods to assess each.
8.5 Identify relationships between body weight and chronic diseases.
8.6 Compare and contrast the diagnoses, characteristics, and treatments of the different eating disorders.
a. Identify eating disorders in the athlete including the female athlete triad and disordered eating.
b. Discuss the characteristics and the treatment of the eating disorders anorexia nervosa and bulimia
nervosa.
Assignments and Other Instructional Materials
The following ready-to-use assignments are available in this chapter of the instructor’s manual:
• Case Study 8: Improving Body Composition
• Worksheet 8-1: Energy Calculation
1
• Worksheet 8-2: Energy Balance (Internet Exercise)
• Worksheet 8-3: Body Mass Index (BMI): Reality vs. Myths
• New! Worksheet 8-4: Chapter 8 Crossword Puzzle
2
• New! Critical thinking questions with answers
Lecture Presentation Outline
4
Key to instructor resource annotations (shown to the right of or below outline topics):
TRA = Transparency acetates: 13e = 13th edition, 12e = 12th edition, 11e = 11th edition, 10e = 10th edition
Website = Available for download from book companion website: HN = student handout
IM = Included in this instructor’s manual: CS = case study, WS = worksheet, CA = classroom activity
132
I. Energy Balance 10e TRA 88
A. Energy balance and weight are maintained when energy in = energy out
II. Energy In: The kCalories Foods Provide
A. Food Composition – Define and explain the following:
1. Bomb calorimeter (Figure 8-1)
B. Food Intake – Define and explain the following: 10e TRA 89
1. Appetite
2. Hunger – Role of the hypothalamus
3. Satiation
III. Energy Out: The kCalories the Body Expends IM WS 8-1
A. Components of Energy Expenditure – Explain the following: 10e TRA 90
1. Basal Metabolism (basal metabolic rate, BMR)
a. Approximately 2/3 of energy expenditure (Figure 8-4)
b. Supports the basic processes of life
c. Resting metabolic rate (RMR)
d. Factors affecting BMR
1. Age
2. Height
3. Growth
2. Physical Activity IM WS 8-2
a. Most variable and changeable factor with regard to energy expenditure
3. Thermic Effect of Food (TEF)
a. Carbohydrate: 5-10%
133
d. Alcohol: 15-20%
4. Adaptive Thermogenesis
B. Estimating Energy Requirements – Estimation of energy requirements is affected by many factors,
including:
1. Gender
IV. Body Weight and Body Composition
A. Defining Healthy Body Weight
1. The Criterion of Fashion 11e TRA 19; IM HN 8-1
B. Body Fat and Its Distribution (Figure 8-7) – Explain: IM CA 8-1
1. Some People Need Less Body Fat – Explain why some people need less body fat
2. Some People Need More Body Fat – Explain why some people need more body fat 10e TRA 93
3. Fat Distribution (Figure 8-8)
a. Visceral fat 11e TRA 20
b. Central obesity (Figure 8-9) 10e TRA 94
c. Subcutaneous fat
V. Health Risks Associated with Body Weight and Body Fat (Figure 8-11) 10e TRA 96
A. Health Risks of Underweight
1. Cannot handle medical stresses
B. Health Risks of Overweight Website HN 8-3
1. Risks of obesity include:
a. Diabetes
b. Hypertension
c. Cardiovascular disease
134
2. Cardiovascular Disease – Cardiovascular disease and obesity have a strong relationship
3. Type 2 Diabetes
4. Inflammation and the Metabolic Syndrome
a. High blood pressure
5. Cancer – Cancer risk increases with weight gain
C. Fit and Fat versus Sedentary and Slim
1. Healthy weight is important
2. Cardiorespiratory fitness is important
VI. Highlight: Eating Disorders
A. The Female Athlete Triad (Figure H8-1) – Explain the following conditions: 10e TRA 103
1. Disordered eating
2. Amenorrhea
B. Other Dangerous Practices of Athletes
1. Food and fluid restrictions
1. Educate about inappropriate dietary habits
1. Characteristics of Anorexia Nervosa
1. Characteristics of Bulimia Nervosa
2. Treatment of Bulimia Nervosa
F. Binge-Eating Disorder – Discuss:
1. Characteristics of binge-eating disorder
1. Occur more commonly in developed nations
2. Learning to appreciate uniqueness
Case Study 8: Improving Body Composition
5
Rick is a healthy 17-year-old high school student who is 5 feet 10 inches tall and weighs 205 pounds. He has
decided to “get a six-pack” over the summer with a diet and exercise program. As part of his new plan, he has
stopped drinking soda and is eating more salads in addition to his usual diet. Besides these changes, he is unclear on
how to proceed to reach his fitness goal. Rick’s mother wants to make sure his approach will not interfere with his
normal growth and development and has asked him to seek reliable information to help him make a reasonable plan.
1. Use the “How to” feature on page 244 to calculate Rick’s BMI. Then use Table 8-4 to determine his weight
category.
135
2. Using the BMI table (Table 8-4) and information in the “How to” feature on page 244, what would be a
reasonable BMI for Rick to initially target? What is his initial weight goal based on this desired BMI? How
many pounds will Rick need to lose to reach this goal? Explain how you arrived at your answer.
3. Use the formula provided in this chapter (p. 236) to calculate Rick’s basal metabolic rate (BMR) at his current
weight of 205 pounds. Remember to convert his weight to kilograms and his height to centimeters (see the
“How to” on p. 240 for conversion factors; recall that 1 m = 100 cm).
4. Rick plans to begin light to moderate weight lifting for an hour 3 days a week and swim at a moderate pace for
30 minutes another 3 days a week. Use Table 8-2 to calculate the kcalories he can expect to expend doing each
of these activities at his current weight. Based on these numbers and assuming Rick takes one day off from
exercise each week, calculate the average number of daily calories that Rick can expect to expend doing these
activities.
5. Rick’s Estimated Energy Requirement (EER) is approximately 3550 kcalories per day. How would you use this
information along with the calculations you made for his BMR and daily kcalorie expenditure from physical
activity to help him set a reasonable daily kcalorie goal for weight loss? Explain your answer.
6. As Rick proceeds to lose weight and increase his muscle mass with exercise, what other measurements besides
BMI and weight may more accurately reflect his progress? Explain your answer.
Answer Key
2. A reasonable initial target BMI is 27, which is approximately 2 units below Rick’s current BMI of 29.4. This
corresponds to a weight of 188 pounds for his height on the BMI chart (Table 8-4). Based on his current weight
of 205 pounds, Rick will need to lose 17 pounds to reach this initial goal weight.
Suggested Classroom Activities
This chapter provides an opportunity to discuss concepts regarding body weight and body composition and often
generates student interest and questions. These topics seem to spark much discussion.
136
Classroom Activity 8-2: Body Composition Assessment: Bioelectrical Impedance
6
Key concept: Assessment of body composition Class size: Any
Materials needed: Scale, height measuring tool, BIA tool, fatfold calipers (optional)
Instructions: In an attempt to demonstrate the difference between body weight and body fat, body composition tools
can be brought into the classroom. If available, obtain a bioelectrical impedance analysis (BIA) tool. This instrument
is simple enough to be used in the classroom. It appears to be high-tech and, as a result, fascinates students. Student
interest often generates questions and discussion and opens informal teachable moments.
To begin the procedure, ask students to volunteer to have their body composition examined. It is wise to make this
voluntary rather than required (be sensitive to issues of privacy in the event that a student declines). Next, determine
the student’s height and weight and enter that information into the device. Follow the instructions provided with the
device to estimate body fatness. To enhance accuracy, the student should be well hydrated, should not have
exercised within the previous 6 hours, and should not have eaten in the previous 2 hours. Body fat measurements
can also be taken with fatfold calipers for comparison purposes. Limitations within all methods of determining body
composition can be discussed. The strengths of BIA include that it can be performed quickly, is noninvasive, and is
easy to transport. Unfortunately, the equipment can be expensive.
How To “Try It” Activities Answer Key
How to Estimate Energy Requirements
The student should first determine his/her weight in kg (weight in lb./2.2) and height in m (height in in./39.37) and
select the appropriate EER equation to use: EER = 662 – (9.53 age) + PA x [(15.91 wt) + (539.6 ht)] for
males, or EER = 354 – (6.91 age) + PA [(9.36 wt) + (726 ht)] for females. The student must also select an
appropriate physical activity factor (PA) using the brief descriptions given in the How To. Finally, the student must
plug the numbers into the EER equation and correctly perform the calculation.
For example, for a 5’6”, 115-lb. female who is 33 years old and exercises 60 min. or more each day:
Wt = 52.27 kg, ht = 1.676 m, age = 33, PA = 1.27
EER = 354 – (6.91 33) + 1.27 [(9.36 52.27) + (726 1.676)] = 2,293 kcal
How to Determine BMI
The student should plug her/his weight and height into one of the equations provided in the How To box to calculate
BMI, evaluate the BMI based on the categories listed in the chapter, and, if the BMI is outside the healthy range,
determine how much she/he should weigh to have a BMI 2 units closer to the normal range. (The weight can be
looked up in a BMI table or calculated: weight = [BMI height in inches2]/703 or BMI height in m2.) For
example, a person who is 5’6” and weighs 115 lb. would have a BMI of (115 703)/662, or 18.6, which is within
the normal range. A person who is 5’1” and weighs 152 lb. would have a BMI of (152 703)/612, or 28.7, would be
overweight, and would need to reduce his/her weight to (26.7 612)/703, or 141 lb., to achieve a BMI of 26.6.
Study Card 8 Answer Key
8. Ideally, a person has enough fat to meet basic needs but not so much as to incur health risks. This range of
healthy body weights has been identified using a common measure of weight and height—the body mass index.
9. Visceral fat that is stored around the organs of the abdomen is referred to as central obesity or upper-body fat.
Much research supports the widely held belief that central obesity—significantly and independently of BMI—
10. b 11. a 12. d
Critical Thinking Questions
7
1. The expression “You are what you eat” is used extensively to explain the concept of energy balance and weight
gain. Based on your understanding of nutrition gathered from reading this textbook, does this phrase accurately
explain the concept of energy balance and weight gain? Consider daily dietary intake pattern as compared with
long-term dietary intake patterns.
2. A person has gone out to dinner with a group of friends, stating that he is “not really hungry.” The restaurant
chosen has a buffet for their food service. The individual goes up to the buffet and fills a large plate with
multiple food choices. What factors would account for this given his initial statement that he is “not really
hungry”?
3. Explain why basal metabolic rate is higher in infants than in adults, and in normal-weight adults as compared to
obese adults.
4. The textbook provides information related to the “criterion of fashion” and the “criterion of health.” Briefly
compare and contrast these two criterions, addressing how they influence perceptions of body weight in society.
5. BMI is used as the main indicator of weight status, yet certain individuals can have high BMIs without being
considered fat. How can this occur?
6. Explain how one’s body composition and fat distribution pattern influence the potential for the development of
chronic disease.
Answer Key
1. Although weight status is reflective of energy obtained from caloric intake, the phrase “You are what you eat”
only provides a glimpse into the concept of energy balance and weight gain. Daily dietary intake patterns are
not in themselves supportive of energy balance, for individuals do not typically eat the same foods each day.
2. There are multiple factors that influence an individual’s food selections. In this scenario, the individual initially
may have been influenced by the social interaction environment that uses food as an accompaniment to social
3. Although much smaller than adults, infants have a higher BMR based on their proportional body surface area.
Infants have a higher proportion of metabolically active body tissues. Their respiratory rate is higher and their
4. The “criterion of fashion” is based on how society defines beauty. It is influenced over time by societal
concepts of what is “in” or fashionable. As such, it changes to incorporate body image perceptions that can have
5. BMI is based on the calculated ratio of measured weight to height. As noted in the text, it is not reflective of
body composition but does provide a statistical indicator of mortality risk. The presence of muscular tissue
6. One’s overall weight can be a factor in the potential development of chronic disease. Individuals who are
obese/overweight as well as those who are underweight are more likely to develop co-morbid conditions.
However, the pattern of body fat deposition may predispose an individual to developing certain chronic diseases
IM Worksheet Answer Key
Worksheet 8-1: Energy Calculation
5. 0.030 189 = 5.7 kcal/min; 5.7 15 = 85.5 total kcal spent
Worksheet 8-2: Energy Balance (Internet Exercise)
Worksheet 8-4: Chapter 8 Crossword Puzzle
1. anorexia nervosa
4. Visceral
7. underweight
10. overweight
139
Worksheet 8-1: Energy Calculation
Using Table 8-2 in your textbook, calculate the amount of expended kcalories for each of the identified activities.
Show each step of the calculation process.
1. Male client weighing 175 pounds who does weight lifting (vigorous effort) for 15 minutes three times a week.
5. Male client weighing 189 pounds who is wheeling himself in a wheelchair for 15 minutes.
140
Worksheet 8-2: Energy Balance (Internet Exercise)
1. The energy balance equation to facilitate weight loss is more in then out over time.
2. In order to maintain body weight, one’s energy intake and output must be balanced over time but not
necessarily equal on a daily basis.
a. True
b. False
3. A 38-year-old male who walks 2 miles per day at a rate of 3 miles per hour would require which caloric intake
to sustain energy?
4. Which statement is true regarding a potential weight gain of 10 pounds per year?
a. If you take in 150 extra kcalories per day but are physically active, this can lead to a weight gain of 10
pounds per year.
5. Which option could lead to cutting 150 kcalories from one’s diet?
a. Eat a two-egg omelet
b. Order a salad with oil and vinaigrette dressing
c. Order a small soda
d. Drink water
141
Worksheet 8-3: Body Mass Index (BMI): Reality vs. Myths
Reality
Myth
If your BMI > 25 you are considered to be overweight.
Only a high BMI affects health status.
If your BMI > 30 you are considered to be clinically
obese.
You only have to worry when your BMI > 40 because
only then you are considered to be morbidly obese.
Using the following data, calculate the client’s BMI and determine whether they are considered to be underweight,
healthy, overweight, or obese.
1. 5 foot 8 inches, 160 pounds
BMI = _______________; client is considered to be ____________________________.
2. 6 foot 2 inches, 220 pounds
BMI = _______________; client is considered to be ____________________________.
142
Worksheet 8-4: Chapter 8 Crossword Puzzle
1
2
3
4
5
6
7
8
9
10
11
12
Across:
Down:
3. _____ is associated with obesity and is a risk factor
for developing type 2 diabetes.
7. Being _____ is associated with the development of
osteoporosis.
10. A BMI of 27 kg/m2 is considered _____.
12. When energy intake equals energy output the body
is said to be in _____.
1. Distorted body image and amenorrhea are
associated with the eating disorder _____.
complications.
5. 3500 kcalories are equivalent to _____ pound(s) of
expenditure.
143
Handout 8-1: The Declining Weight of Miss America
As explained in Chapter 8, the body mass index (BMI) describes relative weight for height. Between the
1930s and 1990s, the BMI of Miss America declined steadily. After the mid-1960s, most fell below 18.5,
the cutoff point indicating underweight with its associated health problems. In the 2000s, fortunately, the
BMI of Miss America rose into the healthy weight range again.
144
Handout 8-2: How To Determine Body Weight Based on BMI
A person whose BMI reflects an unacceptable health risk can choose a desired BMI and then calculate an
appropriate body weight. For example, a woman who is 5 feet 5 inches (1.65 meters) tall and weighs 180
pounds (82 kilograms) has a BMI of 30:
BMI = 82 kg = 30
1.65 m2
or
28 ÷ 0.166 = 169 lb
To reach a BMI of 28, this woman would need to lose 11 pounds. Such a calculation can help a person to
determine realistic weight goals using health risk as a guide. Alternatively, a person could search the table
on the inside back cover for the weight that corresponds to his or her height and the desired BMI.
Height
Factor
Height
Factor
Height
Factor
4’7” (1.40 m)
0.232
5’3” (1.60 m)
0.177
5’11” (1.80 m)
0.139
