Cognitive strategies for reporting portion sizes using dietary recall procedures

Objectives To examine recall strategies used by interview respondents when making judgments about portion size and to better understand how respondents use various portion-size aids. Design Study participants were separated into groups, each using a different set of portion-size estimation aids: (a) 2-dimensional paper aids presented in stacks, (b) 2-dimensional aids, cut out and presented on rings, (c) household-type aids, and (d) a combination of 2- and 3-dimensional aids, many of which are used in national government surveys. Respondents gave a "quick list" of foods consumed the previous day and practiced cognitive thinking skills. Then the interviewer selected at least 2 solid, 2 liquid, and 2 amorphous foods for probing. Respondents were asked to think aloud as they reported how much they ate of each food. Types and frequencies of cognitive strategies used for portion-size estimation were determined. Subjects Interviews of 1 to 1 1/2 hours were conducted with 76 adults aged 18 to 65 years. Participants were recruited to obtain a mix of races, ages, educational levels, and genders. Results The most frequently used strategy was visualization and comparison to aids, Others strategies were known amounts, estimations based on known amounts, visualization of volume or a container, and actions such as pouring or moving hands to the mouth. Respondents preferred aids that were similar in size and shape to actual portions consumed for liquid or amorphous food and preferred the ruler for solid foods. Applications To obtain the best data from dietary recalls, expect answers that are possible for respondents to give, supply respondents with aids that help them recall amounts consumed, and guide respondents to appropriate aids that help them formulate focused responses.