Body Composition

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Body Composition

• Determination,Importance, and Weight Control

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Answer the following questions to yourself

• Is my body weight just right, too high, too low?
  What about my body fat? How do I look in a
  swimsuit?
• Females no matter what the reality of the body
  weight, composition, shape, they feel that their
  values are too high
• Males when asked to select a body silhouette
  that reflects their current one, and the ideal
  they would like to look like, there wasnt a
  difference
• Cultural expectations
• When dealing with the public, you will get more
  questions concerns about body composition /
  weight control than just about anything else we
  deal with.

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Body Composition - The partitioning of body mass
into fat-free mass and fat mass
1)Densities of FW and FFW (water, mineral,
protein) are known, additive, and relatively
constant 2) Percentage of each FF component is
relatively stable 3) Individuals differ only in
the amount of storage fat
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Body Composition Assessment

• Hydrostatic (underwater) weighing Criterion
  measure for determining body composition through
  the calculation of body density
• Archimedes Principle The principle that a
  partially or fully submerged object will
  experience an upward buoyant force equal to the
  weight or the volume of fluid displaced by the
  object (The volume of any object can be measured
  by determining the weight lost by complete
  submersion under water)
• Densitometry The measurement of mass per unit
  volume (foundation of HW based on dividing the
  body into 2 compartments)

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Water 73.8 Mineral 7 Protein 20 (minimal
changes throughout childhood adolescence)
Db increases in a curvilinear fashion from 1.08
to 1.10 g.cc for males 1.08 to 1.095 g.cc for
females (leads to an overestimation of BF)
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Skinfolds - The double thickness of skin plus the
adipose tissue between the parallel layers of
skin most widely used anthropometric estimation
of body composition
1/3 of total fat is estimated to be subcutaneous
represented by the selected skinfold site
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Bioelectrical Impedance Analysis

• Ability to conduct the electrical current is
  directly related to the amount of water and
  electrolytes in the various body tissues
• Accuracy depends on
• Maintenance of normal
• hydration level
• .measure 3-4 h post meal or exercise
• .cautious of caffeine ingestion
• Ambient and skin temperatures
• resistance is higher under cool temps
• than warm temps
• Equations used
• Converting resistance to TBW, Db, fat

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Body Mass Index - A ratio of total body weight to
height
27.3 ? 27.8 ?
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Body Composition Assessment
Used b/c of data from previous slide
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Body Composition Assessment
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Overweight and Obesity
? Puberty 12 yo ? Puberty 10 yo
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Overweight and Obesity
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• The Cellular Basis of Obesity
• Two critical periods
• Infancy
• Adolescence
• Greatest change in size occurs between birth 1
  yr
• Greatest change in is between 10-16 years

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Fat Distribution Patterns
Excess fat in the abdominal cavity pushing
against the abdominal muscles stretching them
out
Soft jiggly no pseudohardness is apparent
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Fat Distribution Patterns
Inhibit fat transfer to from the adipocytes
Enhance transfer/unstable adipose cells
1. Linked to reproductive function 2. Reshaping
is extremely limited
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Fat Distribution Patterns

• Waist-to-Hip ratio High risk values
• 0.9 males
• 0.8 females
• Waist circumference High risk values
• 100 cm (39.4 inches) males
• 88 cm (34.6 inches) females

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Heredity and Body Composition

• 5 of variation in BMI and skinfold thickness is
  genetically transferable
• 25-30 of variation in BF, FFW, and fat
  distribution is genetically transferable
• 30 of transmission of body composition
  variables is linked to cultural factors
• 45-60 of variation in body composition is
  genetically nontransferable

Storage of internal fat is influenced by genetic
factors more than the storage of subcutaneous fat
Nutrient partitioning manipulation of the
macronutrient content of diet - affects the
bodys tendency to gain fat or fat-free mass
- no way to identify who falls into which
category - ?Programmed for fat gain in
response to excess calories?
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The Caloric Balance Equation

• Kilocalorie The amount of heat needed to raise
  the temperature of 1 kg of water 1 degree Celsius
  (1 calorie 0.001 kcal)
• Caloric Balance Equation The mathematical
  summation of the caloric intake () and energy
  expenditure (-) from all sources (quantifies the
  law of conservation of energy)

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The Caloric Balance Equation

• Caloric Balance
• food ingested (kcal)
• - basal or resting metabolic rate (kcal)
• - thermogensis (kcal)
• - work or exercise metabolism (kcal)
• - energy excreted in waste products (kcal)

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The Caloric Balance Equation

• Food Ingested
• Impact of diet on food intake
• Impact of exercise and exercise training on food
  intake
• No clear evidence for a transient reduction or
  increase in food intake following exercise bout
• Active individuals consume more calories than
  sedentary individuals (but generally maintain
  their weight composition at normal levels)

Food regularly consumed during normal
living Restriction of caloric intake
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The Caloric Balance Equation

• Energy intake increases (highly trained and lean)
  or remains unchanged as a result of training
  (untrained and obese)
• When training ceases, energy intake is
  spontaneously reduced
• Does not appear to be matched to the reduced
  energy expenditure
• Leads to a energy balance, regain of lost body
  weight, concomitant elevation of body fat

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The Caloric Balance Equation

• Resting or Basal Metabolism
• Basal Metabolic Rate (BMR) - The level of energy
  required to sustain the bodys vital functions in
  the waking state, when the individual is in a
  fasted condition (8-18 hrs), at normal body and
  room temperature, and without psychological
  stress
• Resting Metabolic Rate (RMR) - the energy
  expended while an individual is resting quietly
  in a supine position
• Liver is largest consumer of energy at rest
  (30) brain (20) muscles (18) heart (10)

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165
1465 kcal/d
65
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Adult males 1500-1800 kcal/day females
1200-1450 kcal/day For each 1 in BF, the RMR
0.6 kcal/hr, or 14.4 kcal/d
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The Caloric Balance Equation

• Impact of diet on resting metabolic rate (RMR)
• Severe caloric restriction decreases RMR
  (discouraging effect of slowing the weight loss)
• The impact of acute exercise on resting metabolic
  rate
• Metabolism is elevated by exercise, but the
  resting metabolism remains constant
• Transient increase EPOC (additional kcal that
  are expended as a result of exercise RMR has not
  been affected)
• A lot of speculation, but little clear evidence
  that an exercise bout changes RMR for 24-48h
  after exercise bout

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The Caloric Balance Equation

• Exercise training and resting metabolic rate
• Research is inconclusive
• Some cases show differences up to 200 kcal/d
• RMR is related to muscle mass, but not totally
  dependent on it (SNS, energy flux?)
• High energy flux heavy training volume with
  caloric balance
• Low energy flux sedentary, but in caloric
  balance
• Weight cycling
• Repeated bouts of weight loss and gain does not
  appear to negatively influence RMR or subsequent
  weight loss
• Has been speculatively associated with upper body
  fat deposition

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The Caloric Balance Equation

• Thermogenesis The production of heat
  (precisely how it occurs has not been determined)
• The impact of diet on the thermic effect of a
  meal
• Total caloric content composition of a meal
• greatest effect occurs with protein
• The impact of exercise on the thermic effect of a
  meal (before or after ? enhanced?)
• Exercise training and the thermic effect of a
  meal
• moderate enhance TEM no effect on RMR
• vigorous decrease TEM elevate RMR

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The Caloric Balance Equation

• The Effect of Diet, Exercise, and Exercise
  Training on Energy Expenditure

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The Caloric Balance Equation

• The Effect of Diet, Exercise Training, and Diet
  Plus Exercise Training on Body Composition and
  Weight
• Physiological Goals
• 1. To lose body fat
• 2. To preserve fat-free weight
• 3. To maintain or improve health
• 4. To maintain/improve performance (i.e
  athletics)
• 5. What determines wt loss success?
• initial status type of diet selected time
  frame inclusion of exercise etc.

Most lose weight strictly for aesthetics
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Restricting water intake while dieting causes a
higher proportion of water to be lost, not less,
which could lead to dehydration.
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Vary considerably not to be interpreted as
values that all athletes competing in a
particular sport should achieve
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Total weight loss is similar in all 3 groups, but
in some cases muscle mass can be gained
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Applications of Training Principles for Weight
and Body Composition Loss and/or Control

• Specificity (diet exercise is recommended)
• Goal is caloric deficit of 3500 - 7000 kcal per
  week (500 - 1000 per day) in order to loss 1-2lb
  per week
• Overload (defined as the attainment of net
  caloric deficit)
• Burning large number of calories is most
  beneficial, for many people this requires low to
  moderate intensity activity that is maintained
  for a long duration
• 300 kcal per session, 3 days per wk plus 2-3
  days resistance exercises 1 day rest

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Applications of Training Principles for Weight
and Body Composition Loss and/or Control

• GOAL
• Maximize decreases in body fat
• Minimize decreases in fat free weight
• Supply adequate nutrition
• Lifestyle changes not a temporary test of
  willpower
• Adaptation
• Early weight loss is due almost entirely to water
  loss
• The longer the deficit is maintained, the greater
  the proportion of fat loss
• Progression
• of calories that can be expended in exercise as
  the individual adapts

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Applications of Training Principles for Weight
and Body Composition Loss and/or Control

• Individualization
• Estimate RMR
• dietary analysis (caloric intake vs expenditure)
• Retrogression/Plateau/Reversibility
• Weight loss is fastest in initial stages
  (glycogen water loss)
• Not a linear pattern (food efficiency may become
  a factor as RMR can decrease with caloric
  restriction)
• Food efficiency an index of the amount of
  calories an individual needs to maintain weight
• Food efficiency decreases after a weight loss
  such that an individual needs fewer calories to
  sustain a given weight
• Maintenance
• Key is exercise training (most cannot handle food
  deprivation alone)
• Weight loss maintenance typically requires 60-90
  minutes of exercise 5-7 d/w

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Application Question

• Would you recommend a series of short, very-low
  calorie diet regimens for quick weight loss or a
  slow steady approach? Why?

Latter approach is better the individual must
get past the early water loss stages and into the
stage where fat loss is proportionally the
greatest. This adaptation will occur in addition
to the specific adaptations to the exercise
training.
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Application Question

• To lose fat, is it better to burn fat by doing
  long duration, low intensity exercise or to burn
  carbohydrate by doing shorter duration, higher
  intensity exercise?

• The important factor in weight loss is to
  establish a caloric deficit no matter which fuel
  is being utilized or what intensity/duration is
  chosen.
• Ballor et al. showed low intensity ex. 283 kcal
  (66 fat) vs. high intensity ex. 280 kcal (26
  fat) ? lost equal amounts of fat
• 2. EPOC considerations