|
Review Questions and Answers
Chapter 5 – Energy Balance and Body Composition
1) Describe what our general energy requirements
are and what they require us to be able to do.
A definition posited by the world health
organisation gives the best answer to this question:
Energy requirement is the energy intake that
will balance energy expenditure when the individual has a
body size and composition and a level of physical activity
consistent with long term good health and that will allow
for maintenance of economically necessary and socially desirable
physical activity. In children and pregnant or lactating women
the energy requirement includes the energy needs associated
with the deposition of tissues or the secretion of milk at
rates consistent with good health.
2) What are the biological levels at which
the composition of the body might be considered?
Four major levels can be identified:
a) Elements: 99% of mass from 6 most abundant
– oxygen, carbon, hydrogen, nitrogen, calcium and phosphorous.
b) Molecular or Macromolecular: Majority water, then lipid,
protein, mineral and salts.
c) Physiological of Cellular: Mass of body cells including
water, protein and mineral content plus extracellular fluids
and solids.
d) Anatomical: Combination of sophisticated methods of body
composition at a tissue and organ related level.
3) How can body fat content be estimated
using skinfold callipers?
This method of estimation is primarily based
on the work of Durnin and Rahaman (1967). Measurements are
taken at four sites on the body: bicep, tricep, subscapular
and suprailiac, and then the sum of these is compared to the
standardised table of body fat measures created by Durnin
and Womersley (1974). The same skinfold thickness in women
and older people indicates a greater percentage body fat than
in men.
4) How can densiometric principles be utilised
to estimate body composition?
Body composition based on densiometric principles
is carried out using two main methods; underwater weighing,
air displacement plethysmography. These methods are based
on how much air or water are displaced by the body in these
mediums. Other methods can are used such as medical imaging,
total body water and dual energy x-ray absorptiometry. When
evaluating body composition the body is generally partitioned
into two compartments; fat mass and fat free mass, with the
Siri equation employed to provide the appropriate densities
of fat and lean tissue.
5) In what ways can energy intake be estimated?
Dietary evaluation including anthropometric,
biochemical and clinical assessment are employed to estimate
energy intake. Both qualitative and quantitative measures
are utilised in dietary evaluation, beginning with simple
food questionnaires to provide simple answers to the questions
of what and how much people are consuming. A food diary is
the next step up in this assessment, and with a weighed amount
of food for consumption very accurate measures of energy intake
can be produced using food composition tables, packaging,
labels, and biochemical analysis.
6) What factors determine energy expenditure?
Total Energy Expenditure =
Basal Metabolic Rate + Thermogenesis + Physical
Activity
7) How can the storage of carbohydrate by
body tissues be manipulated as a result of diet and exercise?
By restricting calorific intake basal metabolic
rate will decrease, facilitating storage to a point, alternatively
an increase in consumption will increase metabolic rate and
storage will be less. These factors will change depending
on the size of the decrease or increase in consumption of
food. If consumption does not meet energy requirements then
stores will be used, similarly if consumption is too high
then excess will be stored (not a desirable situation). An
increase in physical activity is a good way of preventing
obesity and becoming overweight. So storage of carbohydrates
will be lower with higher levels of physical activity and
vice versa.
8) What is the major component of energy
expenditure for a tour de france cyclist and a sedentary individual?
Sedentary Individual: Basal Metabolic Rate
Tour De France Cyclist: Physical Activity
Level
9) Describe the main macronutrient
and energy requirements for endurance exercise.
^ back to top
|
