Determinants of eight-year diet recall ability.

This study investigated how well people can recall their food habits of years ago and identified factors that predict recall ability. We examined the self-reported dietary intakes of 623 people, about one-third of whom were vegetarians. Subjects included cancer cases and controls who were selected as a representative sample of the Adventist Health Study population. We compared the initial (1976) dietary data with data recalled retrospectively in 1984. The initial and retrospective assessments made use of the same food frequency questionnaire for the same 35 food items. Recall ability was measured in two ways: exact recall and recall error. Persons with a stable diet had by far the best recall. Vegetarian status and level of education also were determinants of exact recall, whereas diet stability and education were the most significant determinants of recall error. These results indicate that some individuals, particularly those with a stable diet, those with a vegetarian diet, and those with more education, are able to recall their past dietary practices with reasonable reliability.