Lecture 8 Flashcards
Portion size estimation in dietary assessment. The good, the bad and the ugly
what is the definition of portion size
the amount of food that is actually eaten within a defined eating episode
what are the dietary assessment steps
- measure food intake
- convert food to nutrients
- estimate absorbed intake of nutrients
- evaluate dietary adequacy
what are the sources of error for food and nutrient intakes
- memory / recall
- incorrect use of portion size tools
- quantification skills of respondent
- density factors
what are the cognitive processes in dietary assessment
- perception = amount in relation to aid
- conceptualisation = amount not present
- memory
what are the factors affecting accuracy of portion size estimation
- dietary assessment method
- type of food
- respondent characteristics
what are the characteristics of weight diet records
- exact grams
- largest respondent burden
- outside of home can be difficult
- reactivity
-before - after (amount consumed) - Missing ?
what are portion size estimation tools
24hr diet recall or diet record
estimate volumes (Beans, water and measuring cylinders)
what are the characteristics of 24hr diet recall or diet record
-household measures
- standard measure units
- known packaging size
- visual aids
- categorical size estimations (small, medium and large)
- food models
- hands
what are the possible settings of diet record methods
home versus research clinics / schools or workplaces
what are the ways that diet recall methods can be administrated
interviewer administrated or self administrated
characteristics of computer based self administered recalls
- photos
- common standard measures
- packaging sizes
- shapes / dimensions
what is the recipe dilemma
- ingredients
- quantity
- before cooking : can change after cooking
- yield after cooking
- % consumed by participant
- part eaten
why is pre portioned food great for dietary assessment
easy way of knowing how much someone consumes, , however portion sizes can be inaccurate when comparing to what the person actually consumed
what is the flat slope phenomenon
- large portions : underestimated
- small portions : overestimated
what are examples of amorphous food and why are they an issue in dietary assessment
more difficult to estimate than single unit food
- example : pasta, rice, mashed potato
what is commonly found with pack size and dietary assessment
consumers estimates large portion sizes if food is from a large size pack
NZ FOOD COMPOSITION DATABASE: common standard measures
1 cup=250ml
1 tablespoon=15ml
1 teaspoon= 5ml
three factors of respondent characteristics
- ethnicity and culture
- literacy and numeracy
- age
how is ethnicity and culture affect respondent characteristics
- shared dishes
- different utensils
- eat with hands
litracy and numeracy
Seld administered versus interviewer
Age
-Older adults memory
-Cognitive development children
what are the challenges for research with children
- eat smaller amounts
- varied cognitive ability
- served by others
- more left overs
- food literacy
- proxy respondent
it is not advisable to do recalls for children under the age of
10
what are the challenges with research of children under 10 years
- volume can remain the same if object changes dimension
- size of object depends on eye distance
- reverse action-liquid in original bottle
