Do you get the urge to fib about
your eating style or your diet behavior even if it happens to be on the survey
form? If yes, then you are not alone.
Assessments of diet in researches
are usually based on self-report methods but the validity of these methods is
dependent on the accuracy with which participants record their dietary intake.
Under-reporting in self-reported dietary methods is a well-documented
phenomenon among adults.
But why don't we tell the truth
in surveys? Is it because we want to present a positive image of ourselves to
friends, family and colleagues? It is a bias and it has a term - Social
The existence of systematic bias
in dietary self-reports has been confirmed by many studies and research is on
regarding methods of correcting for measurement error.
In an NIH funded Women's Health
Initiative-Nutrition & Physical Activity Assessment Study (WHI-NPAAS),
Yasmin Mossavar-Rahmani, associate professor of clinical epidemiology and
population health at the Albert Einstein College of Medicine of Yeshiva
University, New York, and her colleagues examined the extent to which
psychosocial and diet behavior factors can affect self-report and how they can
improve the assessment methodologies, viz. food frequency questionnaire (FFQ),
four day food record (4DFR) and 24 hour dietary recall (24HR).
The researchers used doubly
labeled water and urinary nitrogen as biomarkers of objective measures of total
energy expenditure and protein, respectively, in 450 post-menopausal women.
The psychosocial and diet
behavior factors were body image perception, rating on the Social Desirability
Scale, cognitive restraint for eating, uncontrolled eating, and emotional
eating, and number of meals eaten at home.
Following were the findings-
Participants with high social
desirability scores were more likely to under-report on the FFQ for energy and
protein intake compared to those with low social desirability scores.
Participants who ate most of
their meals at home were less likely to under-report on the FFQ for energy and
protein compared to those who consumed a low percentage of meals at home.
In the assessments combining
FFQ, 4DFR, 24HR with age, BMI, race, and the psychosocial and diet behavior
variables, the six psychosocial and diet variables explained 1.98%, 2.24%, and
2.15% of biomarker variation for energy, protein, and protein density
The researchers thus concluded
that adding psychosocial and diet behavior factors to the assessment methods
can strengthen the precision of the assessments by correcting self-report for
The study has been published in the Nutrition Journal.