© 2007 thomson - wadsworth energy balance & healthy eating
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© 2007 Thomson - Wadsworth
Energy Balance & Healthy Eating
© 2007 Thomson - Wadsworth
Energy Balance
© 2007 Thomson - Wadsworth
Components of Energy Expenditure
© 2007 Thomson - Wadsworth
Basal Metabolism• Energy expended to sustain basic life
functionsRespiration, heart beat, nerve
function, muscle tone
• Basal metabolic rate (BMR)Amount of energy expended per hourAccounts for 50-65% TEEBMR measured in morning, fasting
state, & temperature-controlled room
© 2007 Thomson - Wadsworth
Factors Influencing BMR
• Age• Sex• Growth• Body shape• Body composition
• Temperature• Stress• Fever• Thyroid function• Nutritional status
© 2007 Thomson - Wadsworth
Physical Activity
• Accounts for 25-50% of TEE• Factors affecting amount of energy
needed:Time & intensity of activityBody sizeFitness
© 2007 Thomson - Wadsworth
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
© 2007 Thomson - Wadsworth
Assessing Total Energy Expenditure (TEE)
• Direct calorimetry• Indirect calorimetry• Use of stable
isotopes: Doubly labeled water
• Mathematical formulasDRIs
• Estimated Energy Requirements
© 2007 Thomson - Wadsworth
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
© 2007 Thomson - Wadsworth
Estimating Physical Activity Factor
DescriptionPhysical Activity
EquivalentsMen:
PA FactorWomen:
PA Factor
SedentaryOnly activities required for normal independent living
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
© 2007 Thomson - Wadsworth
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
© 2007 Thomson - Wadsworth
Regulation of Energy Balance
Brain uses information to coordinate adjustments in energy intake and expenditure to maintain energy balance on short- & long-term basis.
© 2007 Thomson - Wadsworth
Short-Term Regulation of Food Intake
© 2007 Thomson - Wadsworth
Hunger & Satiety
• HungerBasic physiological need for food
• SatietyPhysiological response to having eaten
enough• Influences
NeuropeptidesGI neural & hormonal signalsPancreasAdipose tissue
© 2007 Thomson - Wadsworth
Appetite
• Desire for foodStimuli may override hunger & satiety Psychological vs physiologicalInfluences
• Appearance, taste, aroma, emotional states
• General vs specific
© 2007 Thomson - Wadsworth
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
© 2007 Thomson - Wadsworth
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
© 2007 Thomson - Wadsworth
BMI & Weight-Related Morbidity & Mortality
© 2007 Thomson - Wadsworth
Other Body Measurements• Body Composition
Adipose vs Muscle, water, & boneDeterminants:
• Genetics, sex, hormones, physical activity, diet
“Normal” body fat levels• Males = 12-20%• Females = 20-30%
• Waist CircumferenceMen ≤ 40 inchesWomen ≤ 35 inches
© 2007 Thomson - Wadsworth
Waist-to-Hip Ratio
• Indicator of body fat distribution
© 2007 Thomson - Wadsworth
Problems with using anthropometric measurements to assess health
• BMI/Weight does not account for body composition,
frame size, age, or ethnicityreported correlations between
categories and health risk skewed• Research
most looks just at weight, not lifestyle factors
Fitness is more important than fatness!
© 2007 Thomson - Wadsworth
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
© 2007 Thomson - Wadsworth
Weight Management
at UVa
© 2007 Thomson - Wadsworth
BMI Data
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© 2007 Thomson - Wadsworth
Students’ Perceptions of their Weight
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© 2007 Thomson - Wadsworth
Students’ Intentions About Weight
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© 2007 Thomson - Wadsworth
© 2007 Thomson - Wadsworth
“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)
© 2007 Thomson - Wadsworth
“…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)
© 2007 Thomson - Wadsworth
“…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)
© 2007 Thomson - Wadsworth
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
© 2007 Thomson - Wadsworth
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.
© 2007 Thomson - Wadsworth
Intuitive Eating
• 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
© 2007 Thomson - Wadsworth
Does it work?
• Weight management
• Physical health
• Psychological health
• Nutritional adequacy
© 2007 Thomson - Wadsworth
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)
© 2007 Thomson - Wadsworth
Physical HealthYES!
“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.
© 2007 Thomson - Wadsworth
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
© 2007 Thomson - Wadsworth
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)
© 2007 Thomson - Wadsworth
Strive for overall wellness• Get adequate sleep• Practice stress and time management• Be physically active• Engage social support
© 2007 Thomson - Wadsworth
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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