Chapter 7: Energy Balance
Student Learning Outcomes
1. Describe energy balance and its use by the body.
2. Compare methods to determine energy use by the body.
3. Discuss methods for assessing and classifying body composition.
4. Explain risk factors associated with overweight and obesity and related health
consequences.
5. Describe how control of energy balance is fundamental to weight loss and maintenance.
6. Discuss why physical activity is a key component in weight loss and maintenance.
7. Describe how modifying lifestyle behaviors fits into a sound and sustainable weight-loss
program.
8. List and discuss characteristics of a sound weight-loss program.
9. Outline the pros and cons of various weight-loss methods for severe obesity.
10.Discuss the causes and treatment of underweight.
11.Evaluate popular weight-reduction methods and determine which are safest and most
successful.
Section 7.1 Concepts: Energy Balance
1. What are the main components of energy balance?
2. How is the energy content of food determined and expressed?
3. What are the main purposes for which the body uses energy?
4. List three factors that increase and three factors that decrease basal metabolic rate.
Dietary Patterns
Almost 75% of adults are overweight or obese.
From early to middle adulthood, the majority of adults gain about 1.1-2.2 lb per year.
60% of adults are affected by obesity-related chronic diseases.
Most reliable and successful weight loss comes from a:
● Commitment to lifestyle behaviors that improve dietary and physical activity patterns
● Combination of improved energy balance, increased physical activity, and behavior
modification
Positive and Negative Energy Balance
Energy Balance: Energy Input = Energy Output
● Energy intake, in the form of food and beverages, matches the energy expended,
primarily through basal metabolism and physical activity
Positive Energy Balance: Energy Input > Energy Output
● Energy intake is greater than energy expended
● Results in weight gain
Negative Energy Balance: Energy Input < Energy Output
● Energy intake is less than energy expended
● Results in weight loss
Energy Intake
, ● Dietary Guidelines recommends focusing on meeting your nutritional needs without
nutrient-dense foods and beverages, while staying within calorie limits
● Overabundance of energy-dense foods and beverages often leads to overconsumption
of calories and excess stores of body fat
● Wide availability of inexpensive and lightly processed palatable food in grab-and-gos,
vending machines, social gatherings, and fast-food restaurants-combined with
supersized portions
● Average adult is 10 lbs heavier than just 10 years ago
Estimating Calorie Content in Food
● Bomb Calorimeter measures kcal content by burning dried portion of food
● Burning food rises temperature of water surrounding chamber holding food
● 1 kcal=amount of heat needed to raise the temperature of 1kg water by 1℃
Energy Expenditure
Thermogenesis
● Thermogenesis is a metabolic process in which the body burns calories to produce heat
● The body uses energy for three general purposes:
(1) Basal metabolism
(2) Physical activity, and
(3) Digestion, absorption, and processing of ingested nutrients
Adaptive Thermogenesis (AT)
Change in the BMR in response to environmental stresses.
Weight loss can lead to very small in AT.
AT is attenuated, or nonexistent, after periods of weight stabilization of neutral energy balance.
AT also represents the increase in nonvoluntary physical activity triggered by reflex responses
(versus intentional physical activity)
● For example, when your temperature begins to drop when exposed to cold
temperatures, the hypothalamus signals your muscles to contract. These involuntary
muscle contractions, known as shivering thermogenesis, serve as a defense mechanism
to warm your body.
Brown Adipose Tissue
Specialized form of metabolically active adipose tissue that is brown in color and participates in
thermogenesis.
Releases energy into environment as heat instead of producing ATP.
● Hibernating animals use brown adipose tissue to generate heat to withstand long winters
In humans, brown adipose tissue contributes as much as 5% of body weight.
Unlike the muscle-contracting shivering thermogenesis, nonshivering thermogenesis occurs in
the brown adipose tissue.
Adaptive Thermogenesis
Nonvoluntary Physical Activity:
, ● Fidgeting and shivering
● Maintenance of muscle tone
● Maintenance of posture
Overeating:
● Increases sympathetic nervous system activity
● Resists weight gain
Brown Adipose Tissue:
● Greater number of mitochondria
● Participates in thermogenesis
Basal Metabolism
● Minimal amount of calories expended in a fasting state to keep a resting, awake body
alive in a warm, quiet environment
● Very low calorie intake decreases basal metabolism 10% to 20% (about 150 to 300 kcal
per day) as the body shifts into a conservation or starvation mode
● Metabolism peaks at one year of age and declines until age 20
● Metabolism remains stable from ages 20 to 60
● Metabolism declines again in older adulthood
Basal Metabolism (BMR)
Minimal amount of calories used by body
● To support a fasting state when resting and awake in warm, quiet environment
Approximately 60% to 80% of total energy needs
● Includes energy needed to maintain heartbeat, respiration by lungs, and activity of other
organs
● Energy needed for basal metabolism varies between individuals
Resting Metabolism (RMR)
● Slightly higher than BMR when person is not fasting
Sample BMR Calculation
Consider a 130-lb woman:
● 2.2 lb for every kilogram (kg): 59kg
● Use rough estimate of BMR of 0.9 kcal per kilogram per hour for an average female,
calculate her BMR
● Use hourly BMR to find BMR for an entire day
○ 59kg X 0.9 kcal/kg= 53 kcal/hour
○ 53 kcal/hour X 24 hr= 1272 kcal/day
BMR: Energy Used by Organs
While a person (130-lb) woman is resting, the percentage of total energy use and corresponding
energy use by various organs are approximately:
Organ% %Total Energy kcal/day
Brain 19% 242
Student Learning Outcomes
1. Describe energy balance and its use by the body.
2. Compare methods to determine energy use by the body.
3. Discuss methods for assessing and classifying body composition.
4. Explain risk factors associated with overweight and obesity and related health
consequences.
5. Describe how control of energy balance is fundamental to weight loss and maintenance.
6. Discuss why physical activity is a key component in weight loss and maintenance.
7. Describe how modifying lifestyle behaviors fits into a sound and sustainable weight-loss
program.
8. List and discuss characteristics of a sound weight-loss program.
9. Outline the pros and cons of various weight-loss methods for severe obesity.
10.Discuss the causes and treatment of underweight.
11.Evaluate popular weight-reduction methods and determine which are safest and most
successful.
Section 7.1 Concepts: Energy Balance
1. What are the main components of energy balance?
2. How is the energy content of food determined and expressed?
3. What are the main purposes for which the body uses energy?
4. List three factors that increase and three factors that decrease basal metabolic rate.
Dietary Patterns
Almost 75% of adults are overweight or obese.
From early to middle adulthood, the majority of adults gain about 1.1-2.2 lb per year.
60% of adults are affected by obesity-related chronic diseases.
Most reliable and successful weight loss comes from a:
● Commitment to lifestyle behaviors that improve dietary and physical activity patterns
● Combination of improved energy balance, increased physical activity, and behavior
modification
Positive and Negative Energy Balance
Energy Balance: Energy Input = Energy Output
● Energy intake, in the form of food and beverages, matches the energy expended,
primarily through basal metabolism and physical activity
Positive Energy Balance: Energy Input > Energy Output
● Energy intake is greater than energy expended
● Results in weight gain
Negative Energy Balance: Energy Input < Energy Output
● Energy intake is less than energy expended
● Results in weight loss
Energy Intake
, ● Dietary Guidelines recommends focusing on meeting your nutritional needs without
nutrient-dense foods and beverages, while staying within calorie limits
● Overabundance of energy-dense foods and beverages often leads to overconsumption
of calories and excess stores of body fat
● Wide availability of inexpensive and lightly processed palatable food in grab-and-gos,
vending machines, social gatherings, and fast-food restaurants-combined with
supersized portions
● Average adult is 10 lbs heavier than just 10 years ago
Estimating Calorie Content in Food
● Bomb Calorimeter measures kcal content by burning dried portion of food
● Burning food rises temperature of water surrounding chamber holding food
● 1 kcal=amount of heat needed to raise the temperature of 1kg water by 1℃
Energy Expenditure
Thermogenesis
● Thermogenesis is a metabolic process in which the body burns calories to produce heat
● The body uses energy for three general purposes:
(1) Basal metabolism
(2) Physical activity, and
(3) Digestion, absorption, and processing of ingested nutrients
Adaptive Thermogenesis (AT)
Change in the BMR in response to environmental stresses.
Weight loss can lead to very small in AT.
AT is attenuated, or nonexistent, after periods of weight stabilization of neutral energy balance.
AT also represents the increase in nonvoluntary physical activity triggered by reflex responses
(versus intentional physical activity)
● For example, when your temperature begins to drop when exposed to cold
temperatures, the hypothalamus signals your muscles to contract. These involuntary
muscle contractions, known as shivering thermogenesis, serve as a defense mechanism
to warm your body.
Brown Adipose Tissue
Specialized form of metabolically active adipose tissue that is brown in color and participates in
thermogenesis.
Releases energy into environment as heat instead of producing ATP.
● Hibernating animals use brown adipose tissue to generate heat to withstand long winters
In humans, brown adipose tissue contributes as much as 5% of body weight.
Unlike the muscle-contracting shivering thermogenesis, nonshivering thermogenesis occurs in
the brown adipose tissue.
Adaptive Thermogenesis
Nonvoluntary Physical Activity:
, ● Fidgeting and shivering
● Maintenance of muscle tone
● Maintenance of posture
Overeating:
● Increases sympathetic nervous system activity
● Resists weight gain
Brown Adipose Tissue:
● Greater number of mitochondria
● Participates in thermogenesis
Basal Metabolism
● Minimal amount of calories expended in a fasting state to keep a resting, awake body
alive in a warm, quiet environment
● Very low calorie intake decreases basal metabolism 10% to 20% (about 150 to 300 kcal
per day) as the body shifts into a conservation or starvation mode
● Metabolism peaks at one year of age and declines until age 20
● Metabolism remains stable from ages 20 to 60
● Metabolism declines again in older adulthood
Basal Metabolism (BMR)
Minimal amount of calories used by body
● To support a fasting state when resting and awake in warm, quiet environment
Approximately 60% to 80% of total energy needs
● Includes energy needed to maintain heartbeat, respiration by lungs, and activity of other
organs
● Energy needed for basal metabolism varies between individuals
Resting Metabolism (RMR)
● Slightly higher than BMR when person is not fasting
Sample BMR Calculation
Consider a 130-lb woman:
● 2.2 lb for every kilogram (kg): 59kg
● Use rough estimate of BMR of 0.9 kcal per kilogram per hour for an average female,
calculate her BMR
● Use hourly BMR to find BMR for an entire day
○ 59kg X 0.9 kcal/kg= 53 kcal/hour
○ 53 kcal/hour X 24 hr= 1272 kcal/day
BMR: Energy Used by Organs
While a person (130-lb) woman is resting, the percentage of total energy use and corresponding
energy use by various organs are approximately:
Organ% %Total Energy kcal/day
Brain 19% 242
