NUTR 2105 Lecture Notes - Lecture 15: Basal Metabolic Rate, Body Composition, Weight Gain
1 May 2018
School
Department
Course
Professor
The Concept of Energy Balance
-
What Energy Balance Is and Why It is Important
An energy imbalance results in weight gain or loss
Positive energy balance: energy intake is more than energy
expended
Weight gain from increased muscle mass, increased adipose
tissue, or both
□
Periods of growth: pregnancy, childhood, and adolescence
□
§
Negative energy balance: energy expended is more than energy
intake
Food intake is reduced, more energy is expended through
exercise, or both
□
Results in weight loss
Fat loss
®
Muscle loss
®
Loss of glycogen or water
®
□
§
○
Foods and beverages provide energy in
Kilocalories consumed are determined using:
Bomb calorimeter: measure kcals in foods and beverages
Results must be adjusted for the physiological fuel
values
®
Physiological fuel values reflect actual kcals
transformed into energy in the body
®
□
Nutrition analysis software or food composition tables
Carb and protein: 4 kcal/ gram
®
Fat: 9 kcal/ gram
®
Alcohol: 7 kcal/ gram
®
□
§
○
Body processes and physical activity result in energy out
Energy needed throughout the day will vary for each individual
based on:
Basal metabolism
□
Thermic effect of food (TEF)
□
Thermic effect of exercise (TEE)
□
Adaptive thermogenesis
□
§
Knowing your energy expenditure provides the basis for either
establishing energy balance to maintain weight or creating an
energy imbalance to gain or lose weight
§
○
Requirements for the Total Daily Energy Expenditure (TDEE)
○
How is Total Energy Expenditure Calculated?
Total Daily Energy Expenditure (TDEE): total kcals needed to meet
daily energy requirements
§
There are many components
§
○
Basal and Resting Metabolic Rate Contribute to TDEE
Basal metabolic rate (BMR): amount of energy spent to meet the
body's basic physiological needs
§
Factors that influence BMR
Lean body mass□
Age □
Gender□
Body size□
Genes□
Ethnicity□
Emotional and physical stress□
Thyroid hormone levels□
Nutritional state□
Environmental temperature□
Caffeine and nicotine intake□
§
BMR is difficult to measure (in a lab, after fasting), so resting
metabolic rate (RMR) is often used
§
○
Physical Activity or Exercise Burns Energy
Thermic effect of exercise (TEE): increase in muscle contraction that
occurs during physical activity
Amount of kcals you need for TEE depends on the activity
performed, duration of activity, and how much you weigh
□
§
Non-exercise activity thermogenesis (NEAT): energy expended from
activities not considered exercise
§
○
Energy Used for Digestion and Absorption is Called the Thermic Effect of
Food (TEF)
Thermic effect of food (TEF): energy used to process the
macronutrients and extract kcals from food
10% of kcals in food consumed is used for TEF
Meals high in protein have greater TEF than those high
in carb, which have greater TEF than those high in fat
®
□
TEF is influenced by:
Type of nutrients consumed, composition of a meal,
alcohol intake, age, and athletic training status
®
□
□
§
○
Energy is Used for Adaptive Thermogenesis
Body's regulation of heat production influenced by environmental
changes such as stress, temperature, or diet
All result in a change in metabolism□
§
Some researches think it explains why two people can have similar
and exercise patterns but differing body compositions
§
○
Factors Involved in Energy Balance
○
How do we Measure Energy Expenditure?
Direct and indirect calorimetry measure energy expenditure
Direct calorimetry measures energy expenditure by assessing
body heat loss w/in a metabolic chamber
□
Indirect calorimetry estimates energy expenditure by
measuring oxygen consumed and carbon dioxide produced w/
a metabolic cart
□
§
Simple calculations can estimate total energy expenditure
Based on age, gender, height, weight, and level of physical
activity
□
Estimated energy requirement (EER) □
§
Calculations can estimate resting metabolic rate (RMR)
Harris-Benedict equation
Based on gender, height, weight, and age
®
Requires an activity factor to determine TDEE
®
Not good for those who fall outside of the norm
®
□
§
○
-
What is Body Composition and How is it Assessed?
Body composition: the ratio of fat tissue to lean body (muscle, bone,
organs)
Usually expressed as percent body fat
§
Important for measuring health risks associated with too much
body fat
§
○
Most Body Fat is Stored in Adipose Tissue
Two types of fat make up total body fat
Essential fat
Essential for the body to function
®
Women have more essential fat (12%) than men (3%)
®
□
Stored fat
Found in adipose tissue
®
Subcutaneous fat (when eat too much) is located under
the skin
®
Visceral fat (good or bad) is stored around the organs in
the abdominal area
Insulates the body from cold temps
◊
Protects and cushions internal organs
◊
®
□
§
Adipose tissue releases fat during negative energy balance
§
In positive energy balance, fat accumulates and adipose cells
expand
§
Brown adipose tissue (BAT) is
Contain more mitochondria and rich in blood
So more metabolically active, so may be reason by
those who are naturally skinnier (can eat whatever they
want and get away w/ it)are that way
®
□
More in adolescents and infants□
Function is to generate heat□
§
○
Body Fat Distribution Affects Health
Central (android) obesity
Excess visceral fat in the abdomen □
Increases risk for heart disease, diabetes, and hypertension□
Visceral fat releases fatty acids that travel to the liver, causing
insulin resistance, increased LDL, decreased HDL, and
increased cholesterol
□
§
Gynoid obesity
Excess fat around the high and buttocks□
More common in women than men□
§
○
Body Composition is Assessed Indirectly
Hydrostatic weighing
Method asses body volume by underwater weighing □
One of the most accurate assessment tools; 2 to 3% margin of
error
□
§
Air displacement plethysmography (BodPod)
Measures air rather than water displacement □
Accurate w/in 3%□
Gold-standard□
§
Dual-energy x-ray absorptiometry (DEXA)
Most accurate method; margin of 1 to 4% □
Use two low-energy x-ray beams to measure bone density
and body mass
□
Body-comp and bone density□
§
Bioelectrical impedance analysis (BIA)
Measures resistance to low energy current as it travels
through muscle and body fat
□
Not as accurate as body density tests□
§
Skinfold caliper
Measured fat in various locations□
Can be accurate if applied by a trained technician□
§
Waist circumference is a quick indicator of health risk. It indicates
where fat is located, not the percentage of body fat.
Increased health risk w/ a normal BMI if:
Greater than 35 inches in women
®
Greater than 40 inches in men
®
□
§
○
How Do We Estimate a Healthy Body Weight?
Height and weight tables can provide a healthy weight range
Provide a recommended desirable weight range for a given
height based on gender and frame size
□
Problematic b/c:
Do not represent population as a whole, original date
was not standardized, and were constructed w/ the
assumption that weight is associated w/ body fat
®
□
Most health experts use BMI rather than height-weight tables
to determine healthy weight
□
§
Body mass index (BMI) calculates body weight in relation to height
Useful screening tool to determine an individual's risk for
disease
□
Interpreting the BMI values
®Ranges and classifications of BMI
□
Obese individuals have a 50 to 100% higher risk of dying
prematurely bothan those at a healthy weight
□
BMI is not a direct measure of % of body fat□
BMI may not be accurate for everyone
Athletes and some individuals: BMI > 25 but have high
muscle mass and low body fat
®
Older adults w/ chronic weight loss: may have health
BMI but significant loss of muscle mass and depletion of
nutrient stores
®
Individuals less than 5 feet in height may have a high
BMI, but not be unhealthy
®
□
Combine indirect measurements to get a better estimate of
body composition
□
§
○
What Are the Health Risks Associated with Body Weight and Body
Composition?
Being underweight increases health risks
Symptomatic of malnutrition, substance abuse, or disease□
Higher risk of anemia, osteoporosis, and bone fractures, heart
irregularities, and amenorrhea
□
Correlated w/ depression and anxiety, inability to fight
infection, trouble regulating body temperature, decreased
muscle strength, and risk of premature death
□
May be unintentional and due to malabsorption associated
w/ diseased such as cancer, inflammatory bowel disease, or
celiac disease
Also mat be due to certain medications, smoking, and
substance abuse
®
□
§
Being overweight increases health risks
Overweight and obesity are associated w/ increased risk of
heart disease, hypertension, stroke, gallstones,
hyperlipidemia, sleep apnea, and reproductive problems
□
Increases risk of certain cancers, including colon, breast,
endometrial, and gallbladder cancer
□
More than 80% of people w/ type 2 diabetes are overweight□
Metabolic syndrome is associated w/ central obesity□
§
○
-
Disordered Eating
Orthorexia: an obsession w/ "healthy" or "righteous" eating
Often begins w/ a person's desire to live a healthy lifestyle
§
Characteristics of the individual
Spends most of his/ her time thinking about food and how it
was prepared, processed, and overall health benefits of the
food
□
Typically does not obsess over calorie content of foods□
§
Contributors to healthy food obsession
Eliminates foods based on learning about a negative health
effect from eating the food
□
§
Restrictive nature can develop into anorexia
§
○
Night eating syndrome: a type of eating, sleeping, and mood disorders
A person consumes a majority of daily cals after the evening meal
and wakes up during the night to eat
§
Characteristics of the individual
Typically does not have an appetite during morning hours□
Low self-esteem, depression, and stress□
May feel guilty, ashamed, or embarrassed while eating at
night, as well as the next morning
□
Common among young adults 18 to 30 years old□
§
○
-
Ch. 14: Energy Balance and Body Composition
Wednesday, April 11, 2018
1:42 PM
The Concept of Energy Balance
-
What Energy Balance Is and Why It is Important
An energy imbalance results in weight gain or loss
Positive energy balance: energy intake is more than energy
expended
Weight gain from increased muscle mass, increased adipose
tissue, or both
□
Periods of growth: pregnancy, childhood, and adolescence □
§
Negative energy balance: energy expended is more than energy
intake
Food intake is reduced, more energy is expended through
exercise, or both
□
Results in weight loss
Fat loss
®
Muscle loss
®
Loss of glycogen or water
®
□
§
○
Foods and beverages provide energy in
Kilocalories consumed are determined using:
Bomb calorimeter: measure kcals in foods and beverages
Results must be adjusted for the physiological fuel
values
®
Physiological fuel values reflect actual kcals
transformed into energy in the body
®
□
Nutrition analysis software or food composition tables
Carb and protein: 4 kcal/ gram
®
Fat: 9 kcal/ gram
®
Alcohol: 7 kcal/ gram
®
□
§
○
Body processes and physical activity result in energy out
Energy needed throughout the day will vary for each individual
based on:
Basal metabolism□
Thermic effect of food (TEF)□
Thermic effect of exercise (TEE)□
Adaptive thermogenesis
□
§
Knowing your energy expenditure provides the basis for either
establishing energy balance to maintain weight or creating an
energy imbalance to gain or lose weight
§
○
Requirements for the Total Daily Energy Expenditure (TDEE)
○
How is Total Energy Expenditure Calculated?
Total Daily Energy Expenditure (TDEE): total kcals needed to meet
daily energy requirements
§
There are many components
§
○
Basal and Resting Metabolic Rate Contribute to TDEE
Basal metabolic rate (BMR): amount of energy spent to meet the
body's basic physiological needs
§
Factors that influence BMR
Lean body mass
□
Age
□
Gender
□
Body size
□
Genes
□
Ethnicity
□
Emotional and physical stress
□
Thyroid hormone levels
□
Nutritional state
□
Environmental temperature
□
Caffeine and nicotine intake
□
§
BMR is difficult to measure (in a lab, after fasting), so resting
metabolic rate (RMR) is often used
§
○
Physical Activity or Exercise Burns Energy
Thermic effect of exercise (TEE): increase in muscle contraction that
occurs during physical activity
Amount of kcals you need for TEE depends on the activity
performed, duration of activity, and how much you weigh
□
§
Non-exercise activity thermogenesis (NEAT): energy expended from
activities not considered exercise
§
○
Energy Used for Digestion and Absorption is Called the Thermic Effect of
Food (TEF)
Thermic effect of food (TEF): energy used to process the
macronutrients and extract kcals from food
10% of kcals in food consumed is used for TEF
Meals high in protein have greater TEF than those high
in carb, which have greater TEF than those high in fat
®
□
TEF is influenced by:
Type of nutrients consumed, composition of a meal,
alcohol intake, age, and athletic training status
®
□
□
§
○
Energy is Used for Adaptive Thermogenesis
Body's regulation of heat production influenced by environmental
changes such as stress, temperature, or diet
All result in a change in metabolism□
§
Some researches think it explains why two people can have similar
and exercise patterns but differing body compositions
§
○
Factors Involved in Energy Balance
○
How do we Measure Energy Expenditure?
Direct and indirect calorimetry measure energy expenditure
Direct calorimetry measures energy expenditure by assessing
body heat loss w/in a metabolic chamber
□
Indirect calorimetry estimates energy expenditure by
measuring oxygen consumed and carbon dioxide produced w/
a metabolic cart
□
§
Simple calculations can estimate total energy expenditure
Based on age, gender, height, weight, and level of physical
activity
□
Estimated energy requirement (EER) □
§
Calculations can estimate resting metabolic rate (RMR)
Harris-Benedict equation
Based on gender, height, weight, and age
®
Requires an activity factor to determine TDEE
®
Not good for those who fall outside of the norm
®
□
§
○
-
What is Body Composition and How is it Assessed?
Body composition: the ratio of fat tissue to lean body (muscle, bone,
organs)
Usually expressed as percent body fat
§
Important for measuring health risks associated with too much
body fat
§
○
Most Body Fat is Stored in Adipose Tissue
Two types of fat make up total body fat
Essential fat
Essential for the body to function
®
Women have more essential fat (12%) than men (3%)
®
□
Stored fat
Found in adipose tissue
®
Subcutaneous fat (when eat too much) is located under
the skin
®
Visceral fat (good or bad) is stored around the organs in
the abdominal area
Insulates the body from cold temps
◊
Protects and cushions internal organs
◊
®
□
§
Adipose tissue releases fat during negative energy balance
§
In positive energy balance, fat accumulates and adipose cells
expand
§
Brown adipose tissue (BAT) is
Contain more mitochondria and rich in blood
So more metabolically active, so may be reason by
those who are naturally skinnier (can eat whatever they
want and get away w/ it)are that way
®
□
More in adolescents and infants□
Function is to generate heat□
§
○
Body Fat Distribution Affects Health
Central (android) obesity
Excess visceral fat in the abdomen □
Increases risk for heart disease, diabetes, and hypertension□
Visceral fat releases fatty acids that travel to the liver, causing
insulin resistance, increased LDL, decreased HDL, and
increased cholesterol
□
§
Gynoid obesity
Excess fat around the high and buttocks□
More common in women than men□
§
○
Body Composition is Assessed Indirectly
Hydrostatic weighing
Method asses body volume by underwater weighing □
One of the most accurate assessment tools; 2 to 3% margin of
error
□
§
Air displacement plethysmography (BodPod)
Measures air rather than water displacement □
Accurate w/in 3%□
Gold-standard□
§
Dual-energy x-ray absorptiometry (DEXA)
Most accurate method; margin of 1 to 4% □
Use two low-energy x-ray beams to measure bone density
and body mass
□
Body-comp and bone density□
§
Bioelectrical impedance analysis (BIA)
Measures resistance to low energy current as it travels
through muscle and body fat
□
Not as accurate as body density tests□
§
Skinfold caliper
Measured fat in various locations□
Can be accurate if applied by a trained technician□
§
Waist circumference is a quick indicator of health risk. It indicates
where fat is located, not the percentage of body fat.
Increased health risk w/ a normal BMI if:
Greater than 35 inches in women
®
Greater than 40 inches in men
®
□
§
○
How Do We Estimate a Healthy Body Weight?
Height and weight tables can provide a healthy weight range
Provide a recommended desirable weight range for a given
height based on gender and frame size
□
Problematic b/c:
Do not represent population as a whole, original date
was not standardized, and were constructed w/ the
assumption that weight is associated w/ body fat
®
□
Most health experts use BMI rather than height-weight tables
to determine healthy weight
□
§
Body mass index (BMI) calculates body weight in relation to height
Useful screening tool to determine an individual's risk for
disease
□
Interpreting the BMI values
®Ranges and classifications of BMI
□
Obese individuals have a 50 to 100% higher risk of dying
prematurely bothan those at a healthy weight
□
BMI is not a direct measure of % of body fat□
BMI may not be accurate for everyone
Athletes and some individuals: BMI > 25 but have high
muscle mass and low body fat
®
Older adults w/ chronic weight loss: may have health
BMI but significant loss of muscle mass and depletion of
nutrient stores
®
Individuals less than 5 feet in height may have a high
BMI, but not be unhealthy
®
□
Combine indirect measurements to get a better estimate of
body composition
□
§
○
What Are the Health Risks Associated with Body Weight and Body
Composition?
Being underweight increases health risks
Symptomatic of malnutrition, substance abuse, or disease□
Higher risk of anemia, osteoporosis, and bone fractures, heart
irregularities, and amenorrhea
□
Correlated w/ depression and anxiety, inability to fight
infection, trouble regulating body temperature, decreased
muscle strength, and risk of premature death
□
May be unintentional and due to malabsorption associated
w/ diseased such as cancer, inflammatory bowel disease, or
celiac disease
Also mat be due to certain medications, smoking, and
substance abuse
®
□
§
Being overweight increases health risks
Overweight and obesity are associated w/ increased risk of
heart disease, hypertension, stroke, gallstones,
hyperlipidemia, sleep apnea, and reproductive problems
□
Increases risk of certain cancers, including colon, breast,
endometrial, and gallbladder cancer
□
More than 80% of people w/ type 2 diabetes are overweight□
Metabolic syndrome is associated w/ central obesity□
§
○
-
Disordered Eating
Orthorexia: an obsession w/ "healthy" or "righteous" eating
Often begins w/ a person's desire to live a healthy lifestyle
§
Characteristics of the individual
Spends most of his/ her time thinking about food and how it
was prepared, processed, and overall health benefits of the
food
□
Typically does not obsess over calorie content of foods□
§
Contributors to healthy food obsession
Eliminates foods based on learning about a negative health
effect from eating the food
□
§
Restrictive nature can develop into anorexia
§
○
Night eating syndrome: a type of eating, sleeping, and mood disorders
A person consumes a majority of daily cals after the evening meal
and wakes up during the night to eat
§
Characteristics of the individual
Typically does not have an appetite during morning hours□
Low self-esteem, depression, and stress□
May feel guilty, ashamed, or embarrassed while eating at
night, as well as the next morning
□
Common among young adults 18 to 30 years old□
§
○
-
Ch. 14: Energy Balance and Body Composition
Wednesday, April 11, 2018 1:42 PM
Document Summary
What energy balance is and why it is important. An energy imbalance results in weight gain or loss. Positive energy balance: energy intake is more than energy expended. Weight gain from increased muscle mass, increased adipose tissue, or both. Negative energy balance: energy expended is more than energy intake. Food intake is reduced, more energy is expended through exercise, or both. Bomb calorimeter: measure kcals in foods and beverages. Results must be adjusted for the physiological fuel values. Physiological fuel values reflect actual kcals transformed into energy in the body. Body processes and physical activity result in energy out. Energy needed throughout the day will vary for each individual based on: Knowing your energy expenditure provides the basis for either establishing energy balance to maintain weight or creating an energy imbalance to gain or lose weight. Requirements for the total daily energy expenditure (tdee) Total daily energy expenditure (tdee): total kcals needed to meet daily energy requirements.
