24-Hour Dietary Recall and

Food Record Method

Chapter 4: Short-term dietary recall and recording methods by Jelia C Witschi

In Nutritional epidemiology By WALTER WILLETT

Introduction

24-Hour dietary recall and food record methodBased on foods and amounts actually consumed by

an individual on one or more specific days

Food frequency questionnaires (FFQ) and diet historiesBased on an individual’s perceptions of usual intake

over a less precisely defined period of time

Data collection methods for 24-h recall• An in-depth interview conducted by a

trained dietary interviewer• Interviewees—subjects, parent, caretake• The dietary interviewer solicits detailed

information about everything the subject had to eat and drink from midnight to midnight of the previous day or over the 24-hour period, either backward or forward

• The importance of a skilled interviewer• Dependent on short term memory and

cooperation

• Food preparation methods, recipe ingredients, brand name of commercial products, use of dietary supplements

• Interviewer (important factors in obtaining complete and accurate information) – Use open-ended questions– Nonjudgmental manner/a neutral attitude /avoid

asking questions in a manner that might influence the subject’s responses

– Use key questions and memory aids

• Accurate quantification of amounts of foods– Amount estimation tool– Food containers– Photographs– Geometric shapes– Number

• Using computer software– The Minnesoda Nutrition Data System

(NDS) /Currently the most commonly used method for dietary surveys in the U.S.

– DAC designed by Academia Sinica• Face to face, telephone interview

– Saving traveling time– “Surprise” effect

Data collection methods for Food record• Food intake is recorded by the subject (or

observer) at the time the foods are eaten to minimize reliance on memory

• Intensive training for the subjects• The fields worker weighs the raw

ingredients, as well as the individual portions of the cook dishes—determine individual food intakes

• Food quantifying tools• Carefully reviewed by a trained nutritionist

Strengths and limitations of the 24-hour dietary recall and food record methods

• Strength (both methods)– Based on actual intake to estimate absolute

amount rather than relative amount of nutrients– Open ended—high level of specificity– Interviews should be sensitive to cultural

difference• Limitation (both method)

– Day to day variation

• Strength (recall vs. food record)– Recall does not need literacy– Recall is less likely to alter eating behavior– Relatively minimal respondent burden

• Limitation (recall vs. food record)– Reliance on memory– The need for a highly trained interviewer

• Limitation (food record)– High level of subject motivation

Number of days and which days• For group means

– Single day • For the distribution of individual intake within the

group, or relationship between individual intake and other variables– More than one day– The number of days is dependent on the studied

nutrient• Work days vs. Weekend days

– Combination of days of the week and not consecutive days

• Estimate of long term intake– Seasonal effect

• For micronutrients such as vitamin A, C– Food frequency questionnaire

Reducing error in data collection• Factors affecting data from dietary recall :

Age, gender, intelligence, mood, attention, consistency of eating pattern

• Comparison of mean energy intake (Recall vs. food record) Table 4-1

Reducing error from dietary recall

1. Considerable training and practice of the interviewers.

2. Providing a relaxed and unhurried atmosphere for the subject.

3. Asking about the previous day’s activities to help jog the subject’s memory

4. Providing a list of foods 5. To use an automated system for collecting the

data in which the computer provides all of the prompts for describing foods at the appropriate level of detail.

-Back-

Reducing error from food record1. Subject’s motivation2. Careful training of subjects in methods of keeping

accurate records3. Emphasizing the importance of the subject’s

contribution to the research4. Stressing the need for timely recording of food

intake5. Encouraging subjects to maintain usual eating

habits during the recording period (They may changer for ease of recording, social desirability).

6. Providing written examples7. To review the food records by trained nutritionist

ASAP.

Reducing error from both methods 1. Between meals snacks2. Eating-out details3. Quantification of portion sizes: Food weighing devices, photographs or food

models of more than one portion size, models of geometric shapes, training of subjects in the use of food models (Table 4-2),

4. For telephone interview, tools (ex: ruler, standard measuring cups or spoons, or a notebook of photographs of different portion sizes for selected foods) can be provided to each subjects to keep at home.

5. Improvement of tools: two-dimensional visuals portraying various sizes of geometric shapes, mounds, and beverage containers to facilitate amount estimation.

6. Inducing motivation: a. convincing participants the importance of

the research and the critical role they play b. Monetary or other types of incentives

-Back-

-Back-

Analysis of food intake data• At individual level, by food group, by meal

pattern (the investigation of the effects of foods when eating together)

• Calculation of nutrient intakes (database of food composition)

• The degree of specificity of food description detail required at the data collection level forcoding and nutrient calculation.

Sources of error in nutrient calculation

• Inaccuracies in the coding of food intake data– data entry check of the computer system,

intensive training and certification of coders/interviewer, 10% or 20% duplicate coding.

• Accuracy and representativeness of the nutrient values in food composition databases.

• The use of outdated nutrient data• Analytical methodology

Validation of 24-hour recalls and food records

• Reporting accuracy• Accuracy of nutrient calculations• Accuracy of assessing usual intake

– how well the selected days of intake represent usual individual intake

Reporting accuracy1. Omissions of food items are more common than

additions• Side dishes or add-ons (Figure4-1)

2. Overestimation appears to be more frequent than underestimation for portion sizes (Table 4-4).

• Beverages: best estimation• Add-ons: poorest estimation

3. The under-reporting of energy intake observed in validation studies of records and recalls is more likely due to omissions in reporting foods than to underestimate of portion sizes

4. The greatest difficulty in estimating amounts was associated with items that could not be separately visualized.

.

5. Overall, recalls tend to underestimate intake by about 10% compared with observed intake (vary considerably among individuals).

6. Flat slope syndrome: Over-estimaton of portion sizes tended to be

greater among those who ate smaller portions and under-estimation among those who ate larger portions.

-Back-

-Back-

Accuracy of nutrient calculations

1. (Table 4-5) Calculated values tend to be higher or lower than the analyzed values

Nutrient dependent

Accuracy of assessing usual intake

1. The use of biochemical indicator for validation (Ch 9)

2. Under-reporting /underestimation• Obesity, athlete, education, motivation, age

(adolescent, elderly)• Nutrient intakes expressed as a percentage of total

energy intake have not been found to be biased, even when energy intake itself was under-reported

3. Reproducibility• Day-to-day variation, seasonal difference• Reproducible at the group level• Reproducible when averaging of multiple days of

intake at the individual level

• There are limitations and potential sources of error for dietary recalls and food records.

• Be careful when using these methods to validate food-frequency questionnaires or diet histories designed for estimating long term usual dietary intake (CH 6).

-Back-

Summary Foods records and 24-hour recalls

1. Consist of specific foods consumed by an individual on one or more days

2. Greater specificity for describing foods and food preparation methods, greater flexibility for analyzing the data

3. Seldom used as the primary method for estimating usual intake in large scale epidemiologic research

4. Important in describing mean values for groups and in validating food frequency questionnaires (most commonly used method)