Lecture 8: Portion Size Estimation Flashcards
What is portion size?
The amount of food that is actually eaten within a defined eating episode
What is happening to portion sizes over time?
They are increasing (e.g. supersized options available) - obesity epidemic
What happens to enviornmental cues with age?
They come into play more e.g. 5-6 year olds will eat more when given more whereas 3-4 year olds will eat the same amount
Does offering larger portion size effect energy intake?
Yes
What are the four steps to dietary assessment?
- Measure food intake
- Convert foods to nutrients
- Estimate absorbed intake of nutrients
- Evaluate dietary adequacy
What does measuring food intake require?
Appropriate method and tool for population, measurement aids.
What does converting foods to nutrients require?
Density factors: mLs to grams
What does evaluating dietary adequacy require?
Reference values for age and sex groups
What are sources of error in dietary assessment?
- Memory/recall
- Incorrect use of portion size tools (interviewer)
- Quantification skills of respondent
- Density factors
What is the 1 cup diet phenomenon?
Cups come in lots of different sizes: People get quite burdened with thinking about exactly how much they have had
What are the cognitive processes of a diet recall?
- Perception - amount in relation to aid
- Conceptualisation - amount not present
- Memory
- Social desirability
Who are more likely to underreport?
Women and overweight people
What factors influence the accuracy of portion size estimation?
- Dietary Assessment Method
- Type of food
- Respondent Characteristics
What do you need to look at when recalling a recipe?
- Ingredients
- Quantities
- Yield before and after cooking
- % consumed
What type of food is really easy to recall?
Pre-portioned food e.g. weet-bix
What is the flat slope phenomenon?
That large portions are underestimated and small portions are overestimated
What type of foods are more difficult to estimate?
Amorphous foods (e.g. rice, pasta, mashed potato) compared to single unit foods
How many mLs is 1 cup?
250mL
How many mLs is 1 tablespoon?
15mL
How many mLs is 1 teaspoon?
5mL
How is density used?
Measure differently shaped foods using volume and measure density: Then can convert into a gram amount
How do ethnicity and culture influence respondent characteristics?
- Shared dishes
- Different utensils
- Eat hands
How do literacy and numeracy influence respondent characteristics?
Self-administered versus interviewer techniques
What are the challenges when doing recalls with children?
- Eat smaller amounts
- Use smaller utensils
- Varied cognitive ability
- Served by others
- More left-overs
- Food literacy
How does age influence respondent characteristics?
Older adults = memory
Children = cognitive development
What are the strengths of using automated cameras?
- Lower respondent burden
- Not memory reliant
- Less reliant on food literacy
- Less subjective error
What are limitations of automated cameras?
- Privacy, ethical considerations
- Software dependent
- Labour intensive
What has seen to be more accurate, computers or people?
Computers
