nutrition2

Question 1

what is energy

Answer 1

the capacity to do work

Question 2

what is energy balance

Answer 2

energy intake - energy expenditure
the amount of dietary energy added to or lost from the body’s energy store after the body’s physiological systems have done all their work for the day

Question 3

energy balance concept

Answer 3

in balance- energy in = energy out - stable body mass
positive balance- energy in > energy out - body mass gain
negative balance - energy in < energy out - body mass loss

Question 4

what is energy intake ?

Answer 4

the metabolizeable energy content of food expressed as kcal

Question 5

what is energy expenditure?

Answer 5

fuels metabolized to support resting metabolic rate 60-80 %, thermic effect of food 6-10% and physical activity 10-30 %

Question 6

what is energy availability?

Answer 6

energy intake - exercise energy expenditure
45 kcal/kg/day available to support non-exercise physiological functions
if EA <30 health status compromised
during weight/fat loss EA should be at 30-45

Question 7

what do prospective methods do ?

Answer 7

provide information on dietary intake but rely on motivation and accurateness of subjects

Question 8

different prospective methods are …

Answer 8

• diet surveys
• weighed food record
• duplicate food collections
• use of food analysis software/database

Question 9

food records strengths

Answer 9

• simple
• fairly accurate (weighed foods more accurate )
• inexpensive
• longer periods needed for intake of fats, cholesterol and some micronutrients

Question 10

food records weakness

Answer 10

• accuracy requires training
• highly motivated participant
• errors in estimating portion size when using household measures
• if unweighed: energy intake underestimated by 50 % and nutrients by 20 %
• after a week, bored less accurate
• women more competent
• dietary change when aware

Question 11

what are retrospective methods?

Answer 11

provide information on past dietary intake

• diet history
• food frequency questionnaires
• dietary recall

Question 12

strengths of dietary recall 24 h

Answer 12

-easy to administer
-time efficient
-inexpensive
low respondent burden

Question 13

weakness of dietary recall

Answer 13

• may not represent usual food intake ( more accurate if repeated)
• underreporting
• memory bias
• underestimating energy and nutrient intake

Question 14

types of gas exchange measurement

Answer 14

• resting
• activity
• whole room

Question 15

what is the doubly labelled technique ?

Answer 15

subject ingests 2^H2^18O- 2^H excreted as H2O independent of metabolic rate
O18 as water and CO2 dependent on metabolic rate
urine analysis- difference btw excretion rates gives CO2 production
VO2=VCO2/RQ

Question 16

what is the factorial approach?

Answer 16

estimate basal or resting EE with an equation

depending on age sex height weight and activity

Question 17

How can using MET throughout the day be even more specific to the activity level

Answer 17

1 MET = 3.5 ml O2/kg/min = 1 kcal/kg/min

sum of METs for the day convert to kcal to BasalEE predicted to ThermicEE

Question 18

Other methods to measure EE

Answer 18

• HR monitoring
• accelerometry
• questionnaire