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Energy Balance and Body Composition

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Burns food and measures the amount of heat given ... (thermic effect of food) 4. Adaptive thermogenesis (energy of adaptation) ... 3. Thermic effect of food: ... – PowerPoint PPT presentation

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Title: Energy Balance and Body Composition


1
Energy Balance and Body Composition
  • Chapter 8

2
Energy Balance
  • 1. Positive energy balance
  • Energy IN gt Energy OUT
  • result stored in adipose tissue
  • necessary during pregnancy, growth.
  • 2. Negative energy balance
  • Energy IN lt Energy OUT
  • result weight loss

3
Weight Maintenance
  • Energy IN Energy OUT

4
Determining Energy Composition
  • Bomb calorimeter.
  • Burns food and measures the amount of heat given
    off this is a direct measure of foods energy
    value.
  • Chemical bonds break and release energy.
  • 1kcal energy required to increase 1kg water 1oC.

5
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6
What is hunger?
  • The feeling that prompts thoughts of food and
    motivates food consumption.
  • A physiological response a feeling.
  • Influenced by nutrients in the bloodstream,
    eating patterns, climate, etc.

7
What is hunger?
  • Appetite-
  • Signals that guide dietary selection.
  • Comes from a psychological state.
  • Can have physiological dimensions (desire for
    a certain food).

8
What is hunger?
  • Satiety-The brain signals the body to stop
    eating (hunger is suppressed).
  • 1. Sensory stimulation meal was eaten.
  • 2. Effects of nutrient digestion, absorption and
    metabolism are felt.
  • 3. Over time, lack of food leads to lack of
    satiety.
  • 4. The cycle begins again.

9
Internal Forces that regulate satiety
  • Cholecystokinin (CCK) and GI distention register
    satiety.
  • The hypothalamus As the sympathetic nervous
    system declines, food intake increases the
    opposite is true.
  • Increased nutrients in the blood.
  • Hormonal and drug affects.

10
Energy use by the body
  • 1. Basal thermogenesis
  • (basal metabolism)
  • 2. Exercise-induced thermogenesis
  • (physical activity)
  • 3. Diet-induced thermogenesis
  • (thermic effect of food)
  • 4. Adaptive thermogenesis
  • (energy of adaptation)
  • Thermogenesis The bodys generation of heat.

11
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12
Energy use by the body
  • 1. Basal metabolism
  • Defined Basic functions in the human body that
    support life.
  • BMR (Basal metabolic rate) The rate at which the
    body spends energy for maintenance activities.
  • Rates vary with age, height, activity, etc.

13
Energy use by the body
  • 2. Physical Activity
  • Defined Voluntary movement of the skeletal
    muscles and support systems.
  • The muscles need energy to move
  • Influenced by duration, frequency and intensity.
  • Energy expended depends on muscle mass, body
    weight and activity.

14
Energy use by the body
  • 3. Thermic effect of food
  • Defined The energy required to aid in
    digestion, absorption, transport and metabolism
    of food.

15
Energy use by the body
  • 4. Adaptive thermogenesis
  • Defined Adjustments in energy expenditure
    related to changes in environment, physiological
    events, trauma or hormone status.

16
Body Composition
  • Muscle, bone, fat and tissue that make up a
    persons body weight.
  • Body weight fat lean tissue (including H2O)
  • A persons weight does not accurately
  • represent their body composition.

17
What is a healthy body weight?
  • Identify weights associated with good health and
    longevity.
  • Weight within the suggested range for height.
  • Fat distribution at low risk of illness and
    premature death.
  • Medical history without risk factors of obesity
    blood pressure, blood cholesterol, etc.

18
Body Mass Index (BMI)
  • Describes relative weight for height.
  • Healthy weight BMI 18.5-24.9
  • Underweight BMI below 18.5
  • Overweight BMI above 25
  • Average BMI in the U.S. 26.5

19
Overweight v. Overfat
  • Health risks of being obese apply to people who
    are overfat
  • Men gt25 body fat
  • Women gt 30-35 body fat
  • Measuring body fat
  • Underwater weighing (most accurate)
  • Skinfold thickness
  • Bioelectrical impedance

20
How much body fat?
  • It depends on the individual person.
  • Women naturally have more body fat
  • 18-32.
  • Men may have 10-25 body fat.
  • Athletes need less body fat.
  • Pregnant women, people living in colder climates
    need more body fat.
  • A person should have enough body fat to meet
    basic needs but not too much to incur health
    risks.

21
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22
Distribution of body fat
  • Critical to health.
  • Intra-abdominal fat stored around the organs of
    the abdomen. (Apple shape)
  • Increased risk of heart disease, stroke,
    diabetes, hypertension and some cancers.
  • Lower-body fat stored around the hips and
    thighs. (Pear shape)
  • Less susceptible to health problems.
  • Most common in women during reproductive years.

23
Body Types
  • Apple shape
  • Intra-abdominal fat.
  • Common in men.
  • Pear shape
  • Lower-body fat
  • Common in women.

24
Health Risks and Body Weight
  • Underweight
  • Malnutrition, Illness, Smoking habits, Extreme
    physical activity.
  • Inadequate immune response and decreased ability
    to fight disease.
  • Infertility.
  • Osteoporosis and bone fractures.
  • Increased weight increases health.

25
Health Risks and Body Weight
  • Overweight
  • Increased risk of diabetes, hypertension, heart
    disease, respiratory disease, etc.
  • Increased mortality.
  • Weight gain gt20 lbs in adulthood correlates with
    increased mortality.
  • Normal weight and unfit people have increased
    mortality.
  • Decreased weight increases health.

26
Health Risks and Body Weight
  • Heart disease (CHD)
  • Obesity and heart disease are related.
  • Central obesity is especially harmful.
  • Inactivity is harmful.
  • Obesity increases risk factors for CHD.
  • Weight loss can lower risk factors for CHD.

27
Health Risks and Body Weight
  • Diabetes
  • 2x more likely to develop in an obese person.
  • Central obesity is related to diabetes.
  • Increased insulin resistance in obese people.
  • Weight gain (11-24 lbs) since age 18 doubles the
    risk of developing diabetes.
  • Weight loss improves glucose tolerance and
    insulin resistance.
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