Transcript Chapter

Energy Balance
& Healthy Eating
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Energy
Balance
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Components of Energy Expenditure
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Basal Metabolism
• Energy expended to sustain basic life
functions
Respiration, heart beat, nerve
function, muscle tone
• Basal metabolic rate (BMR)
Amount of energy expended per hour
Accounts for 50-65% TEE
BMR measured in morning, fasting
state, & temperature-controlled room
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Factors Influencing BMR
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Age
Sex
Growth
Body shape
Body composition
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Temperature
Stress
Fever
Thyroid function
Nutritional status
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Physical Activity
• Accounts for 25-50% of TEE
• Factors affecting amount of energy
needed:
Time & intensity of activity
Body size
Fitness
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Thermic Effect of Food
• Accounts for 5-10% of TEE
• Energy expended to digest, absorb,
transport, metabolize, & store
nutrients following a meal
• Influenced by:
Amount & composition of food
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Assessing Total Energy
Expenditure (TEE)
• Direct calorimetry
• Indirect calorimetry
• Use of stable
isotopes: Doubly
labeled water
• Mathematical
formulas
 DRIs
• Estimated Energy
Requirements
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Estimating Energy Requirements
Males (19 years and older)
EER = 662 - (9.53 x age) + PA x [(15.91 x
wt) + (539.6 x ht)]
Females (19 years and older)
EER = 662 – (6.91 x age) + PA x [(9.36 x
wt) + (726 x ht)]
*Age in years, weight in kilograms, height in meters
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Estimating Physical Activity Factor
Description
Sedentary
Physical Activity
Equivalents
Only activities required for
normal independent living
Men:
PA Factor
Women:
PA Factor
1.0
1.0
Activities equivalent to walking
at a pace of 2-4 mph for the
following distances:
Low Active
1.5 to 3.0 miles/day
1.11
1.12
Active
3 to 10 miles/day
1.25
1.27
Very Active
10 or more miles/day
1.48
1.45
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EER Example
Ex: 20 y.o. female, 5’4”, 123#, walks
to class
• 5’4”  64 ÷ 39.37 = 1.63 m
• 123#  123/2.2 = 55.9 kg
EER = 662 – 6.91(20) + 1.12[(9.36)(55.9) +
(726)(1.63)]
= 662 – 138.2 + 1.12[523.22 + 1183.38]
= 2435
2435 +/- 10% = 2192 – 2679 kcal/day
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Regulation of Energy Balance
Brain uses information to coordinate
adjustments in energy intake and
expenditure to maintain energy
balance on short- & long-term basis.
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Short-Term Regulation of
Food Intake
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Hunger & Satiety
• Hunger
 Basic physiological need for food
• Satiety
 Physiological response to having eaten
enough
• Influences
 Neuropeptides
 GI neural & hormonal signals
 Pancreas
 Adipose tissue
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Appetite
• Desire for food
Stimuli may override hunger & satiety
Psychological vs physiological
Influences
• Appearance, taste, aroma, emotional
states
• General vs specific
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Long-Term Regulation of Weight:
Set Point Theory
• Thermostat analogy
• Energy-wasting proteins convert
energy to heat
• When weight varies from “set point”
Food intake changes
Energy expenditure changes
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Assessing Body Weight
• Body Mass Index (BMI) =
[wt (kg)] / [ht (m)2]
Healthy = 18.5 – 24.9 kg/m2
Overweight = 25-29.9 kg/m2
Obese ≥ 30 kg/m2
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BMI & Weight-Related Morbidity & Mortality
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Other Body Measurements
• Body Composition
Adipose vs Muscle, water, & bone
Determinants:
• Genetics, sex, hormones, physical
activity, diet
“Normal” body fat levels
• Males = 12-20%
• Females = 20-30%
• Waist Circumference
Men ≤ 40 inches
Women ≤ 35 inches
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Waist-to-Hip Ratio
• Indicator of
body fat
distribution
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Problems with using anthropometric
measurements to assess health
• BMI/Weight
does not account for body composition,
frame size, age, or ethnicity
reported correlations between categories
and health risk skewed
• Research
most looks just at weight, not lifestyle
factors
Fitness is more important than fatness!
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What is a healthy weight for you?
• Consider genetics
• Consider your own history
How has your weight changed?
How has your life changed?
• Consider your eating and exercise habits
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Weight Management
at UVa
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BMI Data
80
70
60
50
Natl Male
Natl Female
UVA Male
UVA Female
40
30
20
10
es
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Students’ Perceptions of their
Weight
60
50
40
Natl Male
Natl Female
UVA Male
UVA Female
30
20
10
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ov
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Students’ Intentions About
Weight
60
50
40
Natl Male
Natl Female
UVA Male
UVA Female
30
20
10
ga
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“Everyone is
dieting…”
91% of women recently surveyed on
a college campus had attempted to
control their weight through dieting,
22% dieted “often” or “always”
(Kurth et al., 1995)
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“…even though dieting
doesn’t work…”
• Evidence is inadequate to recommend
commercial or self-help programs [for
weight loss] (Tsai & Wadden, 2005)
• Programs restricting dietary fat and/or
focusing on behavior modification are
generally no more effective than
traditional dieting techniques (Miller, 2006)
• 95% of all dieters will regain their lost
weight in 1-5 years (Grodstein, et al., 1996)
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“…and is, in fact, harmful.”
• Dieting problems include:
 Increased risk of heart disease
 Slowed metabolism
 Nutrient deficiencies
 Loss of muscular strength and endurance
 Interference with concentration and reaction time
 Increased stress, low self-esteem, and feelings of
depression
(NEDA 2006)
• 35% of “normal dieters” progress to pathological
dieting. Of those, 20-25% progress to partial or
full-syndrome eating disorders. (Shisslak & Crago, 1995)
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Health At Every Size
1. Health enhancement
2. Size- and self-acceptance
3. Pleasure of eating well
4. Joy of movement
5. End to weight bias
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Health At Every Size
Pleasure of eating
well
Eating based on internal
cues of hunger and
satiety, appetite, and
individual needs, rather
than on external food
plans or diets.
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Intuitive Eating
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Unconditional permission to eat
when hungry and what food is
desired
Eating for physical rather than
emotional reasons
Reliance on internal hunger and
satiety cues to determine when and
how much to eat
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Does it work?
• Weight management
• Physical health
• Psychological health
• Nutritional adequacy
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Weight Management
YES!
• “Listening to body signals in
determining what, when, and how
much to eat is associated with lower
body mass.”
(Tylka, 2006)
• Those scoring higher in “Intuitive
Eating” had lower BMI values. (Hawks &
Smith 2006)
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Physical Health
YES!
“Size Acceptance and Intuitive Eating
Improve Health for Obese, Female Chronic
Dieters”
(Bacon et al 2005)
 HAES group maintained weight, improved
cholesterol and blood pressure, and
sustained improvements.
 Diet group showed initial weight loss and
metabolic improvement, but by 2 years
weight was regained and little improvement
was sustained.
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Psychological Health
YES!
• HAES vs dieters study
(Bacon et al, 2005)
 Depression: both improved, HAES sustained, diet
group did not
 Self-esteem: HAES group improved, diet group
worsened
• Higher “intuitive eating” scores associated
with higher levels of psychological health (Tylka
2006)
 Self-esteem
 Satisfaction with life, optimism, proactive coping
 Eating disorder symptomatology
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Nutritional Adequacy
YES!
• Intuitive eating correlated with
variety in intake.
• No correlation between intuitive
eating and % junk food consumed.
• Intuitive eating associated with
greater pleasure in eating.
(Hawks & Smith 2006)
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Strive for overall wellness
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Get adequate sleep
Practice stress and time management
Be physically active
Engage social support
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EAT WHAT YOU WANT …
… when you are truly hungry. Stop when
you are full. And eat exactly what
appeals to you. Do this instead of any
diet, and you are likely to maintain a
healthy weight and avoid eating
disorders.
(National Eating Disorders Association, 2002)
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