Chapter 9: Energy Balance and Weight
Management
EXCI 204 — Food for Sport · Chapter Study Notes (with formulas & calculations)
Chapter Overview
In the United States, tempting food surrounds us, convenience is king, and our jobs and lives have
become less physically demanding. The opening story — oversleeping, then ordering a steak, egg, and
cheese croissant sandwich despite “low-calorie, whole-grain, nondairy preferences” — shows how
consumers make concessions to get fuel in the time they have. The consequence: more than 40% of
adult Americans have obesity, increasing their risks of diabetes, heart disease, and cancer.
The chapter covers: (9.1) the obesity epidemic and its causes; (9.2) health consequences of excess fat,
BMI, body composition, and fat location; (9.3) energy balance, components of energy expenditure, and
Estimated Energy Requirements (EER); (9.4) genes vs. environment and the regulation of food intake
and body weight; (9.5) weight-loss goals, guidelines, programs, and weight gain; (9.6) medications,
supplements, and surgery; and (9.7) eating disorders. Math in this chapter: BMI (metric and imperial),
unit conversions, energy from macronutrients, EER equations with PA values, the 3500-Calorie rule,
rates of weight loss, % of body weight goals, TEF and expenditure shares — each boxed where it appears
and collected at the end.
9.1 The Obesity Epidemic
Learning objectives: Discuss the growing obesity epidemic · Identify factors that have led to weight gain
among Americans · Describe environmental, social, and economic changes that could help reverse the
obesity epidemic.
Obesity by the numbers ⭐
Statistic Value
U.S. adults overweight or with obesity More than 70%
U.S. adults with obesity — 1960 13.4%
U.S. adults with obesity — 2000 About 30%
U.S. adults with obesity — today 42.4% (Figure 9.1)
African Americans with obesity 49.6%
Hispanic Americans with obesity 44.8%
U.S. children and adolescents (2–19 y) with obesity Over 18%
Worldwide obesity since 1975 Tripled
Adults worldwide overweight / with obesity 39% overweight; 13% obesity
EXCI 204 · Chapter 9 · Page 1
,• Excess body weight and fat affect men and women of all ages and all racial and ethnic groups;
rates for minorities often exceed those of the general population.
• The term globesity was coined for the global escalation. Once a problem only of high-income
countries, overweight and obesity are now rising in low- and middle-income countries,
particularly in urban settings.
KEY DEFINITION ⭐
overweight — Being too heavy for one’s height, usually due to an excess of body fat. Overweight is
defined as having a body mass index (ratio of weight to height squared) of 25 to 29.9
kilograms/meter² (kg/m²).
KEY DEFINITION ⭐
obesity — A medical condition characterized by excess body fat. It is defined as having a body mass
index (ratio of weight to height squared) of 30 kg/m² or greater.
KEY DEFINITION
globesity — (Described in text) A term coined to reflect the global escalation of obesity and
overweight.
WORKED EXAMPLE — calculated from textbook numbers
How fast has obesity grown?
• 1960 → today: 42.4 ÷ 13.4 ≈ 3.2 times the 1960 rate (an increase of 29 percentage points).
• 1960 → 2000: 13.4% → ≈ 30% (more than doubled); 2000 → today: ≈ 30% → 42.4% (≈ 12 more
points).
EXAM EXAMPLE — FIGURE 9.1
Obesity across America
The line graph shows the U.S. obesity rate rising from about 13–14% (1960–1962) to about 42%
(2017–2018), with the sharpest climb between the 1976–1980 and 1999–2000 surveys (approximate
graph readings). This rise led officials to label the situation an epidemic.
The map shows the % of adults with obesity by state in four bands: 20%–<25%, 25%–<30%, 30%–
<35%, ≥35%.
Interpret the Data — How many states have an obesity rate of 35% or greater? Reading the darkest
band on the map: North Dakota, Iowa, Missouri, Arkansas, Louisiana, Mississippi, Alabama,
Kentucky, West Virginia → 9 states (count read from the printed map; check Appendix L). Only
Colorado (plus DC and Hawaii) falls in the lowest 20–<25% band.
EXCI 204 · Chapter 9 · Page 2
,Why Has the Incidence of Obesity Increased? ⭐
Body weight is affected by biological factors (genetics, age) and lifestyle factors (eating patterns, activity
level), and many outside influences shape those lifestyle patterns — e.g., vending machines with soda,
chips, and candy outside your dorm room vs. hummus, carrots, and fresh fruit in your fridge; well-lit
walking paths vs. no sidewalks. Americans live in an obesogenic environment. The simple answer: we
are eating more and burning fewer calories than 40 or 50 years ago, but the reasons are complex.
KEY DEFINITION ⭐
obesogenic environment — (Described in text) An environment that affects what we eat, how much
we eat, and how much exercise we get in ways that promote weight gain — e.g., plentiful appealing
food and easily avoided physical activity.
Eating more. Since 1960, calorie consumption has increased by about 800 Calories per person per day.
Reasons: changes in food availability, portion sizes, social patterns, and individual choices.
• Availability: supermarkets, fast-food restaurants, and corner stores make palatable, affordable
food available 24 hours a day; advertisements, convenience marts, food courts, and vending
machines bombard us with cues to eat.
• External cues (sight, smell of food) stimulate appetite — usually appetite, not hunger, makes us
stop for ice cream or give in to freshly baked cookies.
• Sociocultural patterns: busy schedules, long commutes, single-parent households, two parents
working full-time → too rushed to cook → prepackaged convenience foods and fast food.
Americans now spend more on food away from home than on groceries; these foods are typically
higher in fat and energy.
• Portion sizes: vending machines offer 20-oz bottles instead of 12-oz cans; a 16-oz coffee drink and
large muffin have about 600 Calories more than the 6-oz coffee and small homemade muffin of
50 years ago. Larger portions → weight gain; small portions → weight loss.
KEY DEFINITION ⭐
appetite — A desire to consume specific foods that is independent of hunger.
KEY DEFINITION ⭐
hunger — A desire to consume food that is triggered by internal physiological signals.
Appetite vs. hunger ⭐
Appetite Hunger
Desire for specific foods Desire for food in general
Independent of hunger; triggered by external Triggered by internal physiological signals
cues (sight, smell, ads)
Example: ice cream on a summer afternoon; Example: contraction of an empty stomach,
cookie smell at the mall ghrelin release (see 9.4)
EXCI 204 · Chapter 9 · Page 3
, Moving less. Fewer Americans work in jobs requiring physical labor; people drive instead of walk or
bike, take elevators instead of stairs, use dryers instead of hanging clothes, and use riding mowers
instead of push mowers. Busy schedules and long workdays leave little time for active recreation; leisure
time goes to TV, video games, tablets, and computers.
• Children: in the 1960s, schools provided daily physical education and children played outdoors
after school; today schools provide fewer opportunities and children spend afternoons indoors
(TV, texting, video games) → burn fewer calories and snack more.
Factors affecting food and activity choices ⭐
Factor type How it promotes weight gain (Figure How it can be improved (Figure 9.3)
9.2)
Environmental A fast-food restaurant on every corner Bike lanes and walking paths → people
and the nearest grocery store miles move more; those who walk or bike to
away → more likely to choose high- work are more active with healthier
calorie fast food body weights and less body fat than
those who drive
Economic Bigger portions increase sales and Making fruits and vegetables accessible
calories: fast-food burger and fry and affordable — e.g., farmer’s
portions are 2 to 5 times larger than markets in inner-city food deserts —
when fast food first became popular; a increases access for low-income families
large soft drink is 32 oz ≈ 300–400
Calories
Sociocultural We interact by cell phone or computer Changes that promote home-cooked
rather than meeting for a walk or tennis family meals and healthier choices at
home can extend to the next
generation
How Can We Reverse the Obesity Epidemic? ⭐
Reversing the epidemic involves more than individual choices — we must address the environmental,
economic, and sociocultural factors contributing to a positive energy balance.
Who can help make the environment less obesogenic
Who Actions described in the text
Community planning Modify buildings, roads, recreational areas, and businesses; grocery
stores with healthy, affordable food; safe, convenient bike paths
and parks
Local, state, national Policies to regulate marketing of unhealthy foods; make nutritious
government options available, accessible, affordable; e.g., some cities tax sugar-
sweetened beverages
EXCI 204 · Chapter 9 · Page 4
Management
EXCI 204 — Food for Sport · Chapter Study Notes (with formulas & calculations)
Chapter Overview
In the United States, tempting food surrounds us, convenience is king, and our jobs and lives have
become less physically demanding. The opening story — oversleeping, then ordering a steak, egg, and
cheese croissant sandwich despite “low-calorie, whole-grain, nondairy preferences” — shows how
consumers make concessions to get fuel in the time they have. The consequence: more than 40% of
adult Americans have obesity, increasing their risks of diabetes, heart disease, and cancer.
The chapter covers: (9.1) the obesity epidemic and its causes; (9.2) health consequences of excess fat,
BMI, body composition, and fat location; (9.3) energy balance, components of energy expenditure, and
Estimated Energy Requirements (EER); (9.4) genes vs. environment and the regulation of food intake
and body weight; (9.5) weight-loss goals, guidelines, programs, and weight gain; (9.6) medications,
supplements, and surgery; and (9.7) eating disorders. Math in this chapter: BMI (metric and imperial),
unit conversions, energy from macronutrients, EER equations with PA values, the 3500-Calorie rule,
rates of weight loss, % of body weight goals, TEF and expenditure shares — each boxed where it appears
and collected at the end.
9.1 The Obesity Epidemic
Learning objectives: Discuss the growing obesity epidemic · Identify factors that have led to weight gain
among Americans · Describe environmental, social, and economic changes that could help reverse the
obesity epidemic.
Obesity by the numbers ⭐
Statistic Value
U.S. adults overweight or with obesity More than 70%
U.S. adults with obesity — 1960 13.4%
U.S. adults with obesity — 2000 About 30%
U.S. adults with obesity — today 42.4% (Figure 9.1)
African Americans with obesity 49.6%
Hispanic Americans with obesity 44.8%
U.S. children and adolescents (2–19 y) with obesity Over 18%
Worldwide obesity since 1975 Tripled
Adults worldwide overweight / with obesity 39% overweight; 13% obesity
EXCI 204 · Chapter 9 · Page 1
,• Excess body weight and fat affect men and women of all ages and all racial and ethnic groups;
rates for minorities often exceed those of the general population.
• The term globesity was coined for the global escalation. Once a problem only of high-income
countries, overweight and obesity are now rising in low- and middle-income countries,
particularly in urban settings.
KEY DEFINITION ⭐
overweight — Being too heavy for one’s height, usually due to an excess of body fat. Overweight is
defined as having a body mass index (ratio of weight to height squared) of 25 to 29.9
kilograms/meter² (kg/m²).
KEY DEFINITION ⭐
obesity — A medical condition characterized by excess body fat. It is defined as having a body mass
index (ratio of weight to height squared) of 30 kg/m² or greater.
KEY DEFINITION
globesity — (Described in text) A term coined to reflect the global escalation of obesity and
overweight.
WORKED EXAMPLE — calculated from textbook numbers
How fast has obesity grown?
• 1960 → today: 42.4 ÷ 13.4 ≈ 3.2 times the 1960 rate (an increase of 29 percentage points).
• 1960 → 2000: 13.4% → ≈ 30% (more than doubled); 2000 → today: ≈ 30% → 42.4% (≈ 12 more
points).
EXAM EXAMPLE — FIGURE 9.1
Obesity across America
The line graph shows the U.S. obesity rate rising from about 13–14% (1960–1962) to about 42%
(2017–2018), with the sharpest climb between the 1976–1980 and 1999–2000 surveys (approximate
graph readings). This rise led officials to label the situation an epidemic.
The map shows the % of adults with obesity by state in four bands: 20%–<25%, 25%–<30%, 30%–
<35%, ≥35%.
Interpret the Data — How many states have an obesity rate of 35% or greater? Reading the darkest
band on the map: North Dakota, Iowa, Missouri, Arkansas, Louisiana, Mississippi, Alabama,
Kentucky, West Virginia → 9 states (count read from the printed map; check Appendix L). Only
Colorado (plus DC and Hawaii) falls in the lowest 20–<25% band.
EXCI 204 · Chapter 9 · Page 2
,Why Has the Incidence of Obesity Increased? ⭐
Body weight is affected by biological factors (genetics, age) and lifestyle factors (eating patterns, activity
level), and many outside influences shape those lifestyle patterns — e.g., vending machines with soda,
chips, and candy outside your dorm room vs. hummus, carrots, and fresh fruit in your fridge; well-lit
walking paths vs. no sidewalks. Americans live in an obesogenic environment. The simple answer: we
are eating more and burning fewer calories than 40 or 50 years ago, but the reasons are complex.
KEY DEFINITION ⭐
obesogenic environment — (Described in text) An environment that affects what we eat, how much
we eat, and how much exercise we get in ways that promote weight gain — e.g., plentiful appealing
food and easily avoided physical activity.
Eating more. Since 1960, calorie consumption has increased by about 800 Calories per person per day.
Reasons: changes in food availability, portion sizes, social patterns, and individual choices.
• Availability: supermarkets, fast-food restaurants, and corner stores make palatable, affordable
food available 24 hours a day; advertisements, convenience marts, food courts, and vending
machines bombard us with cues to eat.
• External cues (sight, smell of food) stimulate appetite — usually appetite, not hunger, makes us
stop for ice cream or give in to freshly baked cookies.
• Sociocultural patterns: busy schedules, long commutes, single-parent households, two parents
working full-time → too rushed to cook → prepackaged convenience foods and fast food.
Americans now spend more on food away from home than on groceries; these foods are typically
higher in fat and energy.
• Portion sizes: vending machines offer 20-oz bottles instead of 12-oz cans; a 16-oz coffee drink and
large muffin have about 600 Calories more than the 6-oz coffee and small homemade muffin of
50 years ago. Larger portions → weight gain; small portions → weight loss.
KEY DEFINITION ⭐
appetite — A desire to consume specific foods that is independent of hunger.
KEY DEFINITION ⭐
hunger — A desire to consume food that is triggered by internal physiological signals.
Appetite vs. hunger ⭐
Appetite Hunger
Desire for specific foods Desire for food in general
Independent of hunger; triggered by external Triggered by internal physiological signals
cues (sight, smell, ads)
Example: ice cream on a summer afternoon; Example: contraction of an empty stomach,
cookie smell at the mall ghrelin release (see 9.4)
EXCI 204 · Chapter 9 · Page 3
, Moving less. Fewer Americans work in jobs requiring physical labor; people drive instead of walk or
bike, take elevators instead of stairs, use dryers instead of hanging clothes, and use riding mowers
instead of push mowers. Busy schedules and long workdays leave little time for active recreation; leisure
time goes to TV, video games, tablets, and computers.
• Children: in the 1960s, schools provided daily physical education and children played outdoors
after school; today schools provide fewer opportunities and children spend afternoons indoors
(TV, texting, video games) → burn fewer calories and snack more.
Factors affecting food and activity choices ⭐
Factor type How it promotes weight gain (Figure How it can be improved (Figure 9.3)
9.2)
Environmental A fast-food restaurant on every corner Bike lanes and walking paths → people
and the nearest grocery store miles move more; those who walk or bike to
away → more likely to choose high- work are more active with healthier
calorie fast food body weights and less body fat than
those who drive
Economic Bigger portions increase sales and Making fruits and vegetables accessible
calories: fast-food burger and fry and affordable — e.g., farmer’s
portions are 2 to 5 times larger than markets in inner-city food deserts —
when fast food first became popular; a increases access for low-income families
large soft drink is 32 oz ≈ 300–400
Calories
Sociocultural We interact by cell phone or computer Changes that promote home-cooked
rather than meeting for a walk or tennis family meals and healthier choices at
home can extend to the next
generation
How Can We Reverse the Obesity Epidemic? ⭐
Reversing the epidemic involves more than individual choices — we must address the environmental,
economic, and sociocultural factors contributing to a positive energy balance.
Who can help make the environment less obesogenic
Who Actions described in the text
Community planning Modify buildings, roads, recreational areas, and businesses; grocery
stores with healthy, affordable food; safe, convenient bike paths
and parks
Local, state, national Policies to regulate marketing of unhealthy foods; make nutritious
government options available, accessible, affordable; e.g., some cities tax sugar-
sweetened beverages
EXCI 204 · Chapter 9 · Page 4
