Intro to sports nutrition Flashcards
Define Anabolism
Energy utalisation/use of ATP to synthesise end products from pre-curser molecules
Define catabolism
the generation or re-synthesis of ATP via the breakdown of carbohydrate fat or protein
Give the three components of energy expenditure and give their relative contributions
RMR
Dietery induced thermogenesis (constant at around 10%)
Thermic effect of exercise (highly variable)
What is the difference between RMR and BMR
BMR is measured immediately after waking and when fasted
As a result it will be slightly lower than RMR
give the kcal/g values for the 4 main macronutrients
carbohydrate = 4 protein = 4 Alcohol = 7 Fat = 9
In terms of energy expenditure, why is the consumption of a high protein diet potentially beneficial
what is the reason for this
processing protein requires more calories than the processing of other macronutrients
therefore this increases dietry induced thermogenesis and so there are less overall calories available /reduced number of effective calories
this is bc. protein needs to go through extra pathways (gluconeogenesis etc.) before it can be used as energy
Define energy balance
dietary energy intake - total energy expenditure
The amount of energy which is added to or lost from energy stores after all the body’s physiological systems have done their work for the entire day
An output from the physiological systems once they have done what they need to do
Define energy availability
dietary energy intake - exercise energy expenditure
the energy which remains after exercise to carry out all other metabolic functions
An input into the body’s physiological systems
what reasons do the IOC give for the avoidance of low energy availability
can impair performance
can impair adaptation to training
can be harmful to brain, reproduction, metabolic and immune function and to bone health
what evidence is there to show that there are possible dangers of low energy availability in terms of down regulation of physiological systems
participants put into low EA, via a fixed amount of exercise and a fixed intake
total energy expenditure decreased over 7 day period so is likely to have been because of a supression of their physiological systems
this caused energy balance to increase because it was being defended by a reduction in energy use by other physiological systems
give some evidence to show how athletes may not have sufficient energy intake post exercise (hormone levels)
ghrelin (drives hunger) was decreased in those exercising
Peptide YY (hunger supression) was increased post exercise
No difference in total food intake, but this demonstrates a lack of compensation for the increased energy expenditure caused by the exercise
what possible explanations are there for high carb diets resulting in lower overall energy intake
less energy dense
high fibre diet so feel more full when not eaten as many kcal
State the guidelines for levels of energy availability
loading/growth = >45kcal/kg of FFM
weight maintainance = around 45kcal/kg of FFM
fat loss = 30 - 45 kcal/kg of FFM
never have <30 kcal/kg of FFM
From the reading, why is energy balance considered to be inferior to energy availability
doesn’t consider that physiological systems could be operating at an unhealthily low level
what 3 reasons did the ACSM give for the development of energy deficiency in athletes
obsessive eating disorders
intentional and rational mismanaged efforts to reduce body size or fatness
inadvertent failure to increase energy intake to compensate for exercise
