254 Introduction to Human Nutrition
the dietary pattern, with respondents either reporting
a “good” dietary pattern in order to project a good
self-image or reporting a “poor” dietary pattern in the
hope of receiving hand-outs or other assistance.
Response rates in short-term recall studies tend to
range from 65% to 95% and depend largely on how,
under what conditions, and from whom the infor-
mation is obtained. A recall may consist of a face-to-
face or telephone interview or of a self-completed
questionnaire.
The 24 hour recall is probably the most widely used
method of obtaining information on food intake
from individuals. It is often used in national surveys
because it has a relatively high response rate and can
provide the detailed information required by regula-
tory authorities for representative samples of differ-
ent population subgroups.
The 24 hour recall is an attempt to reconstruct
quantitatively the amount of food consumed either
in the previous 24 hours or on the previous day. This
period is considered to provide the most reliable
recall of information. With longer periods memory
becomes an increasing limitation. Incomplete recalls
are more likely with self-completed records unless
these records are subsequently checked with the
respondent by the investigator. An example of a 24
hour recall sheet is shown in Figure 10.4.
Traditionally, the food intake has been reviewed
chronologically, i.e., starting from the time the respon-
dent wakes up and going through the day until the
following morning. Recalling daily activities often
assists the respondent to remember food intakes.
Problems encountered in estimating the amounts of
foods consumed are similar to those encountered
with estimated records. Recalls conducted by means
of a face-to-face interview often use aids such as pho-
tographs, food models, and household utensils to
help the respondent to describe how much food was
eaten. In telephone recalls respondents may be pro-
vided with pictures or other two-dimensional aids
prior to the interview to help them to describe the
amounts consumed. There is, however, very little
information on how effective these aids are. For this
type of study a standardized interview protocol, which
is based on a thorough knowledge of local food habits
and commonly used foods, is essential when more
than one interviewer is involved.
In its simplest form, the 24 hour recall consists of
foods and the amounts consumed over a 24 hour
period. In order to obtain suffi cient information to
quantitatively analyze food intakes from a 24 hour
recall, a skilled interviewer will use several “passes” or
stages in questioning the respondent. This procedure
has become known as the multiple-pass 24 hour
recall. This is an interviewing technique consisting of
three to fi ve steps which take the respondent through
the previous day’s food consumption at different
levels of detail. All multiple-pass 24 hour recalls com-
mence with the respondent simply listing all foods
and beverages consumed during the previous 24
hours. The content and number of further steps differ
from study to study. The US Department of Agricul-
ture (USDA) has developed a fi ve-step multiple pass
method comprising the following passes (steps)
(Conway et al., 2003).Pass 1 Quick list: the respondent lists all food and
beverages consumed during the preceding 24 hours
in any order without any prompting or interrup-
tions from the interviewer.
Pass 2 Forgotten foods list: the interviewer asks about
categories of foods, such as snacks and sweets,
which are frequently forgotten.
Pass 3 Time and occasion: the interviewer asks for
details of the times and names of the eating occa-
sions at which foods were consumed.
Pass 4 Detail: the interviewer asks for details, such as
descriptions and preparation methods, and
amounts of foods consumed.
Pass 5 Review: the interviewer goes through the
information probing for any foods which may have
been omitted.A simplifi ed version of the multiple-pass 24 hour
recall consists of three steps:Pass 1 the respondents provide a list of all foods eaten
on the previous day using any recall strategy they
desire, not necessarily chronological.
Pass 2 the interviewer obtains more detailed infor-
mation by probing for amounts consumed, descrip-
tions of mixed dishes and preparation methods,
additions to foods such as cream in coffee, and
giving respondents an opportunity to recall food
items that were initially forgotten.
Pass 3 in a third pass the interviewer reviews the list
of foods to stimulate reports of more foods and
eating occasions.