Energy Requirements and Balance Flashcards
What is a kilocalorie?
The amount of energy required to raise the temperature of 1 gram of water by 1 degree celsius.
1 kcal= 4.184 kJ and 1 kJ = .02389 kcal
How is energy measured?
in units based on transfer of heat (calories) or in units based on performance of work (joules).
Human energy expenditure consists of what 3 principles?
BEE (Basal energy expenditure), TEF (thermic effect of food), and EEPA (energy expenditure of physical activity)
What is BEE?
the minimal energy expenditure required to support body functions in the absence of physical activity or food intake.
What percentage of TEE does BEE account for?
50-70% of kcal/day.
what is RMR?
The kcal your body burns while at rest.
what is the kcal difference between BEE and RMR?
RMR is 10-20% higher than BEE because of the additional energy costs of arousal, posture, and being in a nonfasted state.
What percentage of TEE does TEF account for?
5-15% (adults)
What does direct calorimetry measure?
the transfer of heat from the body to the environment.
how is direct calorimetry performed?
closed environmental chamber (bod pod).
what does indirect calorimetry measure?
respiratory gas exchange; O2 uptake or CO2 release via the lungs is measured as a surrogate for heat production.
what is a respiratory quotient?
the ratio of CO2 produced to O2 consumed, measured by indirect calorimetry, that provides information about whether fat or CHO is being used as fuel.
what is PAL and how is it defined?
Physical Activity Level; defined as the ratio of TEE to BEE.
How many kJoules are in 1 kcal?
4.184 kJ
1 kJ = .02389 kcal
How quickly is liver glycogen stores depleted?
essentially depleted by a 24 hour fast.
How quickly is muscle glycogen depleted?
can be largely exhausted in less than 1 hour during vigorous activity.
What is the main function of stored glycogen?
- to serve a source of glucose for output by the liver when plasma glucose levels decrease
- to provide glucose 6-phosphate for use as fuel in skeletal muscle during exercise.
Substantial net conversion of glucose, AA’s, or alcohol to fat will only occur if what is true?
if the intake of these macronutrients as well as total energy intake is quite high (excess of TEE).
The body is considered to be made up of what six components?
lipid, water, PRO, osseous minerals, cell minerals, glycogen
What % of the following makes up the body? lipids water PRO minerals CHO
14% lipids 62% water 17% PRO 6% minerals 1% CHO
The most widely used assessments of body composition are what?
FM and FFM
What is the difference between FFM and LBM?
FFM includes water, PRO, osseous and soft tissue minerals, and glycogen.
LBM includes the essential fat present in all nonadipose cells and tissues as well as the fat present in the central nervous system (CNS) and bone marrow.
How much difference in % is there between FFM and LBM?
LBM is 2-3% greater than FFM in Men
LBM is 5-12% greater than FFM in Women
What is currently considered the gold standard for assessing body composition?
DEXA (dual-energy x-ray absorptiometry)
