Energy Balance
By Jennifer Turley and Joan Thompson
© 2016 Cengage
Presentation Overview
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Energy Balance Equations
States of Energy Balance
Energy Intake verses Expenditure
Components of Energy Expenditure
BMR
PA
SDA
Principles of Energy Balance
• 1 pound fat = 3500 Calories stored.
• To lose body fat, a Calorie deficit needs
to be created.
• To gain body weight, a Calorie excess
needs to be created.
• Body weight changes
are based on the
relationship of Caloric
(Energy) intake &
Energy Expenditure.
Energy Balance Equations
• If Calories Consumed = Calories Expended
– Body weight is typically maintained. Energy balance occurs.
• If Calories Consumed > Calories Expended
– Weight is typically gained. Positive energy balance occurs.
• If Calories Consumed < Calories Expended
– Weight is typically lost. Negative energy balance occurs.
Energy Intake
• Consumption of Energy Producing
Nutrients in Food and Beverages
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Protein (4 Calories per gram)
Carbohydrate (4 Calories per gram)
Fat (9 Calories per gram)
Alcohol (7 Calories per gram)
• All of the Calories add up!
Energy Expenditure, Part 1
• Basal Metabolic Rate (BMR)
» An amount of energy needed to sustain life
• Voluntary muscle movement
» Calories burned in physical activity (PA)
• The specific dynamic action (SDA) of food (also
called the thermic effect of food)
» Energy required for food digestion & processing
Energy Expenditure, Part 2
Energy Expenditure, Part 3
Basal Metabolic Rate (BMR):
• The energy required by the body to minimally
function (heart to beat, lungs to breathe, …).
• It is determined in a fasting state (12 hours) and
when the body is at complete rest.
• Majority of expenditure in a sedentary person.
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Energy Expenditure
Resting Energy Expenditure (REE):
– Is similar to BMR.
– It considers the amount of energy burned
by a person at rest.
– REE can be measured in the lab or
estimated using the Mifflin-St. Jeor
Equations.
The Mifflin-St. Jeor Equations
Are based on gender, height, weight, and age
REE Formula For WOMEN:
• REE (Calories/day) =
• (10 x W) + (6.25 x H) – (5 x A) - 161
REE Formula For MEN:
• REE (Calories/day) =
• (10 x W) + (6.25 x H) – (5 x A) + 5
W= Weight in Kg (pounds divided by 2.2)
H = Height in centimeters (inches x 2.54)
A= Age in years
Factors Affecting BMR/REE
• Age: BMR is reduced with age.
• Gender: More lean mass means a higher BMR
(gender differences).
• Physiological State: Illness, pregnancy, lactation,
stress, metabolic diseases like hyperthyroidism can
increase the BMR. Starvation or prolonged fasting
decreases BMR up to 80% in women & 60% in men.
• Environmental Temperature: Hot or cold
temperatures increase BMR.
Energy Expenditure, Part 4
Physical Activity (PA):
• The energy expended to perform
physical activity.
• Voluntary muscle movement.
• The total amount of energy
expended increases with body
weight and the intensity of the
exercise.
Physical Activity & Calorie Burn
• The BMR or REE can be used to determine
energy spent or Calorie burn in PA.
• Calories burned = Hours spent in activity x
REE x Activity Factor ÷ 24 hours/day.
• Activity factors
• Sleeping/Reclining: Factor of 1
• Very Light Activity: sitting or standing in a
small space: Factor of 1.5
• Light Activity: moving without sweating:
Factor of 2.5
• Moderate Activity: moving and sweating:
Factor of 5.0
• Strenuous Activity: all out efforts that cannot
be sustained for more than a few minutes
without exhaustion: Factor of 7.0
Energy Expenditure, Part 5
Specific Dynamic Action (SDA):
• The food processing charge.
• Also called the thermic effect of food.
• ~10% of the total number of Calories consumed
is required for the digestion, absorption &
assimilation of nutrients into the body.
• Metabolism is increased when fed.
Some
Summary Points
• Energy balance is the state of
energy intake verse energy
expenditure.
• Intake occurs with food
consumption.
• Expenditure occurs by BMR,
PA, & SDA.
• Weight gain & body fat
accumulation occurs
with positive energy
balance.
• Weight loss & fat mass
reduction occurs with
negative energy
balance.
References for this presentation are the same as those
for this topic found in module 4 of the textbook