NS 210 – Unit 3 Seminar Measuring Diets and Interview Techniques Jennifer Neily, MS, RD, CSSD, LD...
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Transcript of NS 210 – Unit 3 Seminar Measuring Diets and Interview Techniques Jennifer Neily, MS, RD, CSSD, LD...
NS 210 – Unit 3 Seminar
Measuring Diets and Interview Techniques
Jennifer Neily, MS, RD, CSSD, LDRegistered/Licensed DietitianKaplan University
Reasons for Measuring Diet
• “TO IMPROVE HUMAN HEALTH”
• 4 Major Uses Of Dietary Intake Data– Assessing and monitoring
intake– Formulating and evaluating
government and agricultural policy
– Epidemiologic research– Commercial purposes
Assessing and Monitoring Food and Nutrient Intake• Ensuring adequacy of the food
supply
• Estimating the adequacy of dietary intakes of individuals and groups
• Monitoring trends in food and nutrient consumption
• Estimating exposure to food additives and contaminants
Figure 1
Source: Journal of the American Dietetic Association 2010; 110:1638-1645 (DOI:10.1016/j.jada.2010.08.018 )
Copyright © 2010 American Dietetic
Figure 3
Source: Journal of the American Dietetic Association 2010; 110:1638-1645 (DOI:10.1016/j.jada.2010.08.018 )
Formulating and Evaluating Government Health & Agricultural Policy
• Planning food production and distribution
• Establishing food production and distribution
• Establishing programs for nutrition education and disease risk reduction
• Evaluating the success and cost-effectiveness of nutrition education and disease risk reduction programs
Conducting Epidemiologic Research
• Studying the relationships between diet and health
• Identifying groups at risk of developing diseases because of their diet and/or nutrient intake
Commercial Purposes
• Data from national nutrition surveys are used by the food manufacturers to develop advertising campaigns or new food products
Measuring Diet
• Most widely used indirect indicator of nutritional status
• Estimating intake can be difficult– Weakness of data-gathering
techniques– Human behavior– Natural tendency of intake– Limitations of nutrient
composition tables and databases
Methods for Measuring Intake• 24-hour recall• Food Record or Diary• Food Frequency
Questionnaires (FFQs)• Diet History• Duplicate Food Collections• Food Accounts• Food Balance Sheets• Photographic and Digital
Video Methods
24-Hour Recall• Strengths
– Requires less than 20 minutes
– Inexpensive– Easy to administer– Low respondent
burden– Can provide detail info
on types of food consumed
– Probability sampling possible
– More objective than dietary history
– Does not alter usual diet
• Limitations– One recall is seldom
representative of a person’s usually intake
– Underreporting/ overrreporting occurs
– Relies on memory– Omissions of dressings,
sauces, and beverages can lead to low estimates of energy intake
– May be a tendency to overreport intake at low levels and overreport intake at high levels of consumption
– Data entry can be very labor intensive
Food Record or Food Diary
• An extensive record of log including brands and portions of all foods eaten over the course of several days or weeks.
• A diary may include more information like when, where, and with whom.
One month “Billy C” client food record
Food Record or Diary
• Strengths– Does not depend
on memory– Can provide
detailed intake data
– Can provide data about eating habits
– Multiple-day data more representative of usually intake
– Reasonably valid up to 5 days
• Limitations– Requires high degree
of cooperation– Response burden can
result in low response rates when used in large national surveys
– Subject must be literate
– Takes more time to obtain data
– Act of recording may alter diet
– Analysis is labor intensive and expensive.
– Must know portions and be able to estimate
Food Frequency Questionnaires (FFQ)
• Assess energy and/or nutrient intake by determining frequency of intake
• Usually 150 foods or less. What food and how often
• May take 7 – 60 minutes depending on complexity of FFQ
• May provide visual pictures/graphics to help assess portion
Food Frequency Questionniares
• Strengths– Usually self
administered– Computer read– Modest demand on
respondents– Relatively inexpensive
for large sample sizes– May be more
representative of usual intake than food diary
– Design can be based on large population data
– Considered by some as the method of choice for research on diet-disease relationships
• Limitations– May not
represent usual foods or portion sizes chosen
– Intake data can be compromised when multiple foods are grouped within single listings
– Depend on ability of subject to describe diet
Block Questionnaires
• Very popular in research setting
• Solid history of validatoin• Evidence based results
used in hundreds of research studies.
• Multiple versions: long, short, fruits/veggies, meat, soy, nutrients, adults, children, physical activity
Diet History
• Strengths– Assesses
usually nutrient intake
– Can detect seasonal changes
– Data on all nutrients can be obtained
– Can correlate well with biochemical means
• Limitations– Lengthy
interview process
– Requires highly trained interviewers
– Difficult and expensive to code
– May tend to overestimate nutrient intake
– Requires cooperative respondent with ability to recall usual diet
Food Accounts
• Strengths– Suitable for use
with large sample size
– Can be used over relatively long periods
– Gives data on dietary patterns and habits of families and other groups
– Less likely to lead to alterations in diet than some other methods
– Relatively economical
• Limitations– Does not
account for food losses
– Respondent literacy and cooperation necessary
– Not appropriate for measuring individual food consumption
Food Balance Sheet• Strengths
– Can give a total view of a country’s food supplies
– Indicates food habits and dietary trends
– Sued to plan international nutrition policies and food programs
– May be the only data available on a country’s food consumption practices
• Limitations– Accuracy of
data may be questionable
– Only represents food available for consumption
– Does not represent food actually consumed
– Does not indicate how food was distributed
– Does not account for wasted food
Other Interview Techniques
• Duplicate Food Collection Method
• Photographic and Video Records
• Computerized Techniques
p. 294
Issues in Dietary Measurement
• Validity– Ability of an instrument to
measure what it is intended to measure
• Reproducibility– The ability of a method to
produce the same estimate on two or more occasions
• How Many Days?– It is important to know how long
a dietary intake must be measure before a sufficiently reliable estimate of usual intake is obtained
Estimating Portion Sizes
• Photographs of food• Geometric Shapes• Measuring Devices• Lifelike plastic food
models
Estimating Portion Sizes…
Portion Distortion!
FRENCH FRIES 20 Years Ago
Today
210 Calories
2.4 ounces
How many calories are intoday’s portion of fries?
National Heart Lung and Blood Institute
FRENCH FRIES 20 Years Ago
Today
210 Calories
2.4 ounces
National Heart Lung and Blood Institute
610 Calories6.9 ounces
How long will you have to walk leisurely in order to burn those extra 400 calories?*
*Based on 160-pound person
Maintaining a Healthy Weight is a Balancing ActCalories In = Calories Out
National Heart Lung and Blood Institute
*Based on 160-pound person
If you walk leisurely for 1 hour and 10 minutes you will burn approximately 400 calories.*
Calories In = Calories Out
National Heart Lung and Blood Institute
320 calories
How many calories are in today’s turkey sandwich?
TURKEY SANDWICH 20 Years Ago
Today
National Heart Lung and Blood Institute
320 calories
TURKEY SANDWICH 20 Years Ago
Today
National Heart Lung and Blood Institute
820 calories
*Based on 160-pound person
If you ride a bike for 1 hour and 25 minutes,you will burn approximately 500 calories.*
Calories In = Calories Out
National Heart Lung and Blood Institute
CHICKEN CAESAR SALAD
20 Years Ago Today
390 calories 1 ½ cups
How many calories are in today’s chicken
Caesar salad?
National Heart Lung and Blood Institute
CHICKEN CAESAR SALAD
20 Years Ago Today
390 calories 1 ½ cups
National Heart Lung and Blood Institute
790 calories
3 ½ cups
Calorie Difference: 400 calories
Bagel
Calorie difference: 210
• 25 years ago:– 140 calories– 2 inch diameter
• Today:– 350 - 400 calories– 6 inch diameter
Blueberry Muffin
Calorie difference: 290
• 25 years ago:– 210 calories– 1.5 ounces
• Today:– 500 calories– 4 ounces
Chocolate Chip Cookie
Calorie difference: 220+++
• 25 years ago:– 55 calories– 1.5 inch diameter
• Today:– 275 - 600 calories– 3.5 - 4 inch diameter
Overview of Chapter 3
• Research Design Considerations– Correlation Studies– Case Control Studies– Cohort studies
• Factors that influence selection of dietary methods
• Different Techniques in Measuring diet– Strengths and Limitations
• Validating Dietary Methods
Stuff you need to know!
• Always check announcements and your email.
• Unit 5 midterm coming up. Information posted in Doc Sharing. It’s worth 140 points – 14% of your grade!
• New sections in Doc Sharing: – APA info, samples and formatting– Turnitin.com and plagiarism