Lecture 8 Flashcards

Portion size estimation in dietary assessment. The good, the bad and the ugly

1
Q

what is the definition of portion size

A

the amount of food that is actually eaten within a defined eating episode

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2
Q

what are the dietary assessment steps

A
  • measure food intake
  • convert food to nutrients
  • estimate absorbed intake of nutrients
  • evaluate dietary adequacy
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3
Q

what are the sources of error for food and nutrient intakes

A
  • memory / recall
  • incorrect use of portion size tools
  • quantification skills of respondent
  • density factors
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4
Q

what are the cognitive processes in dietary assessment

A
  1. perception = amount in relation to aid
  2. conceptualisation = amount not present
  3. memory
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5
Q

what are the factors affecting accuracy of portion size estimation

A
  1. dietary assessment method
  2. type of food
  3. respondent characteristics
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6
Q

what are the characteristics of weight diet records

A
  • exact grams
  • largest respondent burden
  • outside of home can be difficult
  • reactivity
    -before - after (amount consumed)
  • Missing ?
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7
Q

what are portion size estimation tools

A

24hr diet recall or diet record

estimate volumes (Beans, water and measuring cylinders)

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8
Q

what are the characteristics of 24hr diet recall or diet record

A

-household measures
- standard measure units
- known packaging size
- visual aids
- categorical size estimations (small, medium and large)
- food models
- hands

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9
Q

what are the possible settings of diet record methods

A

home versus research clinics / schools or workplaces

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10
Q

what are the ways that diet recall methods can be administrated

A

interviewer administrated or self administrated

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11
Q

characteristics of computer based self administered recalls

A
  • photos
  • common standard measures
  • packaging sizes
  • shapes / dimensions
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12
Q

what is the recipe dilemma

A
  • ingredients
  • quantity
  • before cooking : can change after cooking
  • yield after cooking
  • % consumed by participant
  • part eaten
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13
Q

why is pre portioned food great for dietary assessment

A

easy way of knowing how much someone consumes, , however portion sizes can be inaccurate when comparing to what the person actually consumed

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14
Q

what is the flat slope phenomenon

A
  • large portions : underestimated
  • small portions : overestimated
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15
Q

what are examples of amorphous food and why are they an issue in dietary assessment

A

more difficult to estimate than single unit food
- example : pasta, rice, mashed potato

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16
Q

what is commonly found with pack size and dietary assessment

A

consumers estimates large portion sizes if food is from a large size pack

17
Q

NZ FOOD COMPOSITION DATABASE: common standard measures

A

1 cup=250ml
1 tablespoon=15ml
1 teaspoon= 5ml

18
Q

three factors of respondent characteristics

A
  • ethnicity and culture
  • literacy and numeracy
  • age
19
Q

how is ethnicity and culture affect respondent characteristics

A
  • shared dishes
  • different utensils
  • eat with hands
20
Q

litracy and numeracy

A

Seld administered versus interviewer

21
Q

Age

A

-Older adults memory

-Cognitive development children

22
Q

what are the challenges for research with children

A
  • eat smaller amounts
  • varied cognitive ability
  • served by others
  • more left overs
  • food literacy
  • proxy respondent
23
Q

it is not advisable to do recalls for children under the age of

A

10

24
Q

what are the challenges with research of children under 10 years

A
  • volume can remain the same if object changes dimension
  • size of object depends on eye distance
  • reverse action-liquid in original bottle
25
Q

characteristics of 24hr recall in teens and children

A
  • neutral and non judgemental
  • siblings and parents
  • table ideal (50%)
  • wide variety in sizes of household measures
26
Q

what are active approaches to dietary assessment

A

remote food photography and digital food records

27
Q

how does remote food photography and digital food records work

A

foods photographed before and after eating on a 45 degree angle

images transferred wirelessly in real time

28
Q

what is the analysis of remote food photography and digital food records

A
  • manual image analysis
  • automated image analysis
29
Q

what is passive approach to dietary assessment

A

automated cameras

30
Q

what are the strengths to automated cameras

A
  • lower respondent burden ?
  • not memory reliant
  • less reliant on food literacy
  • less subjective error
  • measure contextual factors
31
Q

what are the limitations

A
  • privacy, ethical considerations
  • software dependent
  • currently labour intensive
  • image quality
  • quantification of food
32
Q

future Directions: technology

A

-Reactivity
-Complement current methods
-Automate
-Equipment and software accessible