energy intake and expenditure Flashcards
how to break down the word ‘deaminase’ to work out its function?
ase = enzyme de = removal amine = amine group
so deaminase = enzyme that helps with the removal of amine group
can you get energy from micronutrients?
no, they don’t give energy only help with the process
what is the law of energy and how is it predominantly used in the body?
energy cannot be created or destroyed, just moved from one form to another
most chemical energy in the body goes to heat (80-85%) so not very efficient
what is the gross efficiency equation?
(work accomplished / energy expended) x100
what is the net efficiency equation?
(work accomplished / energy expended - resting energy expenditure) x 100
what is the equation of work efficiency?
(work accomplished / energy expenditure - energy expenditure in unloaded) x 100
takes into account 0W
what is the equation for delta efficiency?
(change in work accomplished / change in energy expenditure) x 100
what are the 2 harder ways to measure energetic efficiency?
work and delta efficiency
what is the energy content per gram of lipids, carbohydrates and protein and alcohol?
what is the digestibility of each nutrient and the resulting usable energy?
lipid - 9.45 kcal - 95% - 9 kcal
carbohydrate - 4.3 kcal - 97% - 4 kcal
protein - 5.65 kcal - 92% - 4 kcal
varies depending on nitrogen content
alcohol - 7 kcal - 100% - 7 kcal
what are the proportions that energy expenditure occurs in?
basal metabolism - 60-75%
admr, bmr and rmr
thermogenesis - 10%
tef and dit
physical activity - 15-30%
tee and eea
in what conditions will body weight remain stable?
when Total Daily Energy Intake (TDEI) = Total Daily Energy Expenditure (TDEE)
what happens when TDEI is less than TDEE?
more energy expenditure than intake
body uses stored energy to make up the difference (when this imbalance occurs over a prolonged period)
what are the main organs which use energy during rest and what proportion of total energy do they use?
liver - 20% brain - 19% skeletal muscle - 18% (significantly increases during exercise) kidneys - 10% heart - 7%
what does ADMR stand for?
components of energy expenditure
average daily metabolic rate
what does bmr and rmr stand for?
components of energy expenditure
basal metabolic rate
resting metabolic rate
resting rate will be higher as not in such strict resting conditions as in a lab
what is tef and dit?
components of energy expenditure
thermic effect of food (digestion and absorption)
diet induced thermogenesis
tef=dit (the same)
what does tee stand for?
components of energy expenditure
thermic effect of exercise
as heat produced during exercise
what does eea stand for?
components of energy expenditure
energy expenditure for physical activity
describe the usage of the direct calorimetry chamber to measure metabolic rate?
pros and cons?
small insulated chamber with ventilation
measures energy expenditure in the form of heat - O2 inspired and CO2 expired
cons: expensive, not ptable, need trained people
pros: can be made into a suit (not much better)
describe the usage of the respiratory chamber to measure metabolic rate?
pros and cons?
measurement of oxygen in and carbon dioxide out (hours-days)
pros: food intake can be measured and urine and faeces can be collected (measure energy and nitrogen balance)
cons: expensive and need highly trained people
how can you use measurement of inspired and expired gas to measure resting metabolic rate?
what is this measurment called?
what else can it measure?
what are the pros and cons?
indirect calorimetry - measure the relative contribution of CO2 and O2 in each breath
can also use to understand amount of fat and CHO being burned
pros: immediate analysis and continuous measurement and measure more people than direct calorimetry chamber and non-invasive
cons: doesn’t distinguish between carbs and fat
describe the usage of doubly labelled water to measure metabolic rate?
pros and cons?
2H2 18O
can measure and track the water in body
pros: free living
cons: expensive
difference between energy cost in very light compared to strenuous activities?
very light: 3-5 kcal/min
strenuous: more than 13 kcal/min
which factors determine amount of energy burned during running?
distance and body mass
1kcal per kg BM per km
what are the effects of prolonged existance at the lower limits of energy?
1000-1500 kcal per day anaemia amenorrhea decreased body mass low bone mineral density
what are some of the ways to measure energy intake?
issues with this type of measurement?
self report:
(but people will under report by roughly 20%)
24h recall
3/7 day food diary
food frequency questionnaire
diet history (cross between 24h recall and food frequency questionnaire)
what most accurate way to measure energy intake and why?
conduct a 3 day weighted food diary
2 weekdays and 1 weekend day
allows calories and macro/micro nutrient intake to be measured
as 7 days produces less high quality data
which eternal factors may increase or decrease resting metabolic rate?
increase - caffeine, carbohydrate intake, exercise, protein, food
decrease - starvation, hot temperature
what equipment is needed to measure indirect calorimetry with a cortex?
hair net
mask
turbine
turbine casing
