Lecture 18 - Dietary Assessment Challenges and How to Overcome them Flashcards
it is quite common for people to report very low energy intakes when reporting what they eat. if they are under reporting their energy can we believe their nutrient intakes
no not really
what is under reporting
deliberate or unintentional omission or underestimation of foods
what is under-eating
process of diet reporting can make people change their eating habits
what is the mean intake of a 19-30y old male from the adult nutrition survey (2008)
11.9MJ
what is the mean intake of a 19-30y old female from the adult nutrition survey (2008)
8.4MJ
what is a method of identifying low energy reporters
“doubly labeled water”
doubly labeled water technique can determine
degree of diet underestimation
how accurate is doubly labelled water
very accurate estimation of free living energy expenditure (only 1-2% error)
what is meant by energy balance in terms of dietary assessment
if they are in energy balance
the energy they report to be eating should be = to their energy expenditure
what are 3 forms of indirect calorimetry
- douglas bag
- portable gas analysis
- on line gas analysis
what does doubly labelled water contain
stable isotopes : deuterium and oxygen 18
what does doubly labelled water estimate
CO2 production without needing breathing apparatus
how does doubly labelled water work
drink a small amount of doubly labelled water and collect urine samples to determine how quickly isotopes disappear from body
what are the two ways we lose oxygen from the body
through urine and breathing out CO2
how do we know how much of the doubly labelled water is lost through CO2 without a breathing apparatus
measure the amount of oxygen lost in the urine, calculate difference by the doubly labelled water oxygen that wasnt lost in urine