Energy Balance Powerpoint Presentation...

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1. Energy Balance
When a person maintains a healthy body
weight: Energy In = Energy Out
Copyright 2005 Wadsworth Group, a division of Thomson Learning

2. ENERGY BALANCE
Energy In - depends on the amount and
kind of food eaten
-Hunger-the physiological response to a
need for food triggered by chemical
signals from the hypothalamus
-Appetite-response to the sight, smell,
thought, or taste of food that triggers
eating
-Satiation-the feeling of fullness &
satisfaction during a meal
-Satiety-the feeling of fullness &
satisfaction after a meal

3. ENERGY EXPENDITURE
Energy Out – depends
primarily on 3 factors:
-Basal Metabolism
-Physical activity
-Thermic effect of food -the
energy required to process food;
5-10% of energy needs

4. Components of Energy
Expenditure
Copyright 2005 Wadsworth Group, a division of Thomson Learning

5. Components of
Energy Expenditure
•Basal metabolic rate (BMR):
energy needed to maintain body
processes at rest
•For most adults, BMR = ~2/3 of
daily energy output
Copyright 2005 Wadsworth Group, a division of Thomson Learning

6. Copyright 2005 Wadsworth Group, a division of Thomson Learning

7. Body Weight vs.
Body Composition
•Body weight = fat + lean tissue
(including water)
•Body composition – the proportions
of muscle, bone, fat, and other tissue
that make up a person’s total body
weight
•A higher percent body fat is
associated with a lower BMR
Copyright 2005 Wadsworth Group, a division of Thomson Learning

8. Body Weight Distribution
Copyright 2005 Wadsworth Group, a division of Thomson Learning

9. Body Composition
•Methods used to assess body fat
1. Fatfold measures – thickness of fat
below skin measured using a caliper
at various sites (triceps, subscapular,
abdomen)
2. Hydrodensitometry - underwater
weighing; the “gold standard” for %
body fat, but not readily available

10. Body Composition
3. Bioelectrical impedance – uses a
low-intensity electrical current to
measure % body fat
4. Air displacement plethysmography
the amount of air displaced by the
body measured while sitting inside
a chamber
5. Dual Energy X-ray absorptiometry
(DEXA) - low dose X-rays that
differentiates fat-free soft tissue, fat
& bone

11. Body Composition
Analysis of measures
1. Value of anthropometric measures
depends on:
a) Clinician’s skill
b) Equipment accuracy
c) Interpretation of values
2. Body composition can also be altered
by fluid retention, dehydration,
exercise

12. ENERGY EXPENDITURE
Voluntary Activity – energy
expenditure depends on:
1. Muscle mass
2. Body weight
3. Activity level – duration &
intensity

13. Copyright 2005 Wadsworth Group, a division of Thomson Learning

14. Copyright 2005 Wadsworth Group, a division of Thomson Learning

15. Estimating Energy
Requirements
Formulas are available to estimate energy
needs based on weight & level of physical
activity
•Gender-women generally have a lower
energy requirements than men
•Age-reduction in energy expenditure is
about 5% per decade
•Body size-a tall, thin person requires more
energy than a short, wide person due to
greater heat lose over larger surface area
Copyright 2005 Wadsworth Group, a division of Thomson Learning

16. Estimating Energy
Requirements
•Physical activity-level varies with
level of intensity, gender and body
size
•Growth-pregnant woman and
children have their own sets of
energy equations
Copyright 2005 Wadsworth Group, a division of Thomson Learning

17. Estimating Energy
Requirements
•For men = 662-9.53 x age + physical
activity [(15.91 x wt) + (539.6 x ht)]
•For women = 354 – 6.91 + physical activity
x [(9.36 x wt) + (726 x ht)]
•Physical Activity Factor 1.0 – 1.48
•Stress factor

18. Severe Stress
•Acute conditions – major infections,
trauma, surgery, burns
•Characterized by increased need as
a result of increased BMR due to:
1. Rapid tissue breakdown
(negative nitrogen balance)
2. Heightened immune function
3. Repair of damaged tissues

19. Severe Stress
•Hypermetabolism peaks after 3-4
days; subsides by 7-10 days
•Failure to meet protein/energy
needs -> organ failure
•High stress often accompanied by
poor appetite & G.I. Problems
•Drugs may further alter nutritional
status

20. Severe Stress
•Chronic conditions – “wasting
syndromes” that develop gradually &
persist long-term as a result of
disease
•Energy – to spare protein & meet
needs due to stress, fever, etc.

21. Wasting Syndromes
•Congestive Heart Failure – reduced blood flow
due to coronary heart disease, hypertension,
obesity, severe stress
Nutritional consequences:
1. Increased energy needs due to
increased work load of heart &
lungs
2. Anorexia – cardiac cachexia
•Chronic Obstructive Pulmonary Disease (COPD) –
persistent obstruction of airflow due to emphysema &
chronic bronchitis caused by smoking &/or environmental
pollution
1. Increased energy needs for breathing

22. Wasting Syndromes
•Cancer – uncontrolled growth of malignant cells/tumors
•Nutritional consequences:
Cachexia – wasting assoc. with anorexia &
increased BMR
Contributing factors are:
1. Early satiety
2. Fatigue
3. Pain
4. Psychological stress
5. Cancer therapies 6.
Nutrient losses
7. Metabolic alterations

23. Wasting Syndromes
•HIV Infection (AIDS) – fatal disease of the
immune system
•Nutrition consequences:
Protein-energy malnutrition/wasting due to:
1. Anorexia related to psychological stress,
pain, lethargy & dementia, drug therapy,
cancer (Kaposi’s sarcoma)
2. Nutrient losses due to diarrhea and
malabsorption
3. Increased metabolism due to fever and
infections