Energy Balance Body Composition

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Energy BalanceBody Composition

• Immediate (proximate) influences
• Long term influences

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Gaining Losing weight

• Gaining or losing weight depends on
• Energy intake vs. energy expenditure
• How much extra weight you carry depends on
• Genetic factors
• Childhood weight
• Behavioral factors
• Social factors

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Energy Balance

• Energy balance
• energy intake energy expenditure
• Energy intake kcal from food
• Energy expenditure energy expended at rest
  during physical activity

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Energy Expenditure breakdown

• BMR
• Physical activity
• Thermic Effects
• Cost of food processing

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Energy Balance

• Basal Metabolic Rate (BMR)
• Energy expended to maintain base, or resting,
  functions of the body
• highest proportion (65) of total energy budget
• More muscle increases your BMR
• BMR decreases with age
• 3-5 per decade after 30
• Estimating BMR
• body weight (kg) 1.0 kcal/kg/hour

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So, obese people have lower BMR, right?
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Factors affecting BMR
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Energy Balance

• Thermic Effect of Food (TEF)
• Energy expended to process food
• 5-10 of total energy budget
• 500 kcal meal costs 25 - 50 kcal to process
• Fats require little energy to digest, transport
  absorb
• Proteins Carbs require more

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Physical Activity

• 20-35 of total energy budget
• Includes everything above basal level
• Sitting, standing, walking
• Moving large muscles requires more Energy
• Calculating Energy expenditure
• Energy Cost (kcal/kg/min) Time (min)
• Do a couple

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Genetic factors

• Different hypotheses explain the impact of
  genetics on body fat
• Thrifty Gene Theory
• Set-point Theory
• Leptin Theory

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Thrifty Gene Theory

• H1 individuals with the gene use less energy (at
  all times) than people who do not possess the
  gene
• More efficient fat storage
• Lower metabolic rates
• Evolutionary story Protection against starvation
  during lean times
• Applied to American Indian populations with high
  rates of obesity diabetes
• Evidence No direct little indirect

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Set-Point Theory

• H1 Body is tuned to maintain weight within a
  narrow range, or set-point
• Evidence
• Rebound weight gain among dieters
• Occasional over-eating usually does not result in
  weight gain
• Can change set point through consistent, long
  term changes in diet exercise

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Leptin Theory

• Leptin hormone produced by adipose cells
• Binds to neurons in satiety center in brain
  inhibits neurons that stimulate feelings of
  hunger
• Increased production reduces food intake, body
  weight and body fat

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Childhood weight

• Childhood weight gain is often carried into
  adulthood. Critical periods
• Gestation early infancy
• Ages 5-7
• Adolescence
• Behaviors learned in childhood influence adult
  behaviors
• Food choices
• Activity levels
• Overweight children have increased risk of heart
  disease and premature death as an adult

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Increase in childhood obesity
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Behavioral Choices

• Food Choices
• Balanced diet
• Overeating dietary fat increases obesity faster
  than overeating carbs or proteins
• Why?
• Less energy required to digest fats than other
  two
• More easily stored as adipose tissueno
  conversion necessary

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Behavioral Choices

• Hunger vs. Appetite
• Appetite may promote overeating
• Satiety mechanism malfunction
• Hormone or sensory receptor malfunction
• Increase or decrease satiety

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Social Factors

• Social factors influence our diet
• Family or cultural traditions
• Holidays and celebrations
• Easy access to high-fat foods
• Less physically active lifestyles
• Societal expectations of the perfect body

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What is a healthful body weight?

• Appropriate for your age
• Maintained without constant dieting
• Is acceptable to you
• Based on family history of body shape and weight
• Promotes healthful eating habits and allows for
  regular physical activity

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Evaluating body weight

• Actual weight is not the only factor to consider
• Determining if a persons body weight is
  healthful should include
• Determining the Body Mass Index (BMI)
• Measuring body composition
• Assessing the pattern of fat distribution

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Evaluating body weight

• Body Mass Index BMI
• BMI weight (kg) / height (m)2
• BMI values below 18.5 or above 30 have increased
  risks of health problems

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Disorders Energy intake

• Underweight having too little body fat to
  maintain health
• BMI less than 18.5 kg/m2
• Increases risk of infection and illness
• Overweight
• BMI of 25 - 29.5 kg/m2
• Some health risks most importantly, adopt
  healthier lifestyle to avoid becoming obese

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Obesity Morbid obesity

• Obesity Having excess body fat that adversely
  effects health
• BMI 30 - 39.9 kg/m2
• BMI gt 40 kg/m2 morbidly obese
• Body weight exceeds 100 of normal
• Morbid obesity body weight exceeding 100 of
  normal, creating a very high risk for serious
  health complications

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Excess Death among overweight people
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Declining weight of Miss America
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Distribution of Body Weights in U.S. Adults
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Achieving maintaining healthy weight

• Healthful weight change requires
• Gradual change in energy intake
• Regular and appropriate physical exercise
• Application of behavior modification techniques

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Techniques for losing weight

• Follow recommended serving sizes
• Reduce intake of high-fat and high-energy foods
  (20)
• Regular physical exercise (of ANY kind will do,
  but which kinds preferentially burn fat?)
• Increase energy expenditure
• Increase BMR

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Gaining weight

• Eat 500 to 1,000 extra kcal/day
• Eat frequently throughout the day
• Maintain a balanced diet
• Avoid tobacco products
• depresses appetite increase BMR
• Regular exercise with resistance training
• Promotes conversion of calories to lean muscle
  rather that fat

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Gaining weight

• Supplements?
• Studies continue to show no effect of AA and
  protein supplements
• No gains in muscle mass and strength, nor in
  performance
• Including androstenedione (Mark McGuire)
• Some effects of this supplement are increased
  LDLHDL levels (why bad?) mood disturbances
• Also, those unfortunate (if youre a male)
  feminizing characteristics

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How many kcals do we need?

• Manual calculation
• BMR (women) body weight (kg) 0.9 kcal/
  kg/hour
• BMR (men) body weight (kg) 1.0 kcal/ kg/hour
• 77.3 kg 1 24 1855 kcal
• Activity some percentage of BMR Ex 70
• 1855 kcal 0.70 1299 kcal
• 1855 1299 3154 kcal
• How many are you eating? Recall
• Fats 9 kcal/gram
• Carbs 4 kcal /gram
• Proteins 4 kcal/gram