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Article Excerpt
An understanding of food consumption and the challenges associated with changing consumption patterns are critical to improving human health and well-being. One barrier to understanding consumption is the difficulty in measuring what people eat. Dietary recall studies, such as the National Health and Nutrition Examination Survey (NHANES) and the Continuing Survey of Food Intakes by Individuals (CSFII), have been used extensively (Thompson & Byers, 1994) to estimate food consumption and to give insight into dietary inadequacies. However, some nutrition researchers have questioned the accuracy and validity of portion-size estimation to quantify dietary intake (e.g., Cypel, Guenther, & Petot, 1997). It is important that dietary data such as portion-size estimation be as accurate as possible (McGuire, Chambers, Godwin, & Brenner, 2001; Mertz, 1992; Young & Nestle, 1995). Other authors have suggested that the accuracy of information obtained from older respondents may be lower than that obtained from younger ones (Taylor-Davis & Smiciklas-Wright, 1993). If this is true, the data used to determine the critical diet-related issues facing the elderly population may be less accurate than desired. This is of added importance because the proportion of elderly in the population is rising annually (U.S. Bureau of the Census, 1994).
Dietary recall places substantial cognitive demands on the respondent--requiring an in-depth search of memory, estimation, and judgment skills (Baranowski & Domel, 1994; Fries, Green, & Bowen, 1995). Until recently, little has been known about these cognitive demands (Buzzard & Sievert, 1994). Hence, the National Center for Health Statistics (NCHS) has cited the need for additional research in this area (U.S. Centers for Disease Control, 1994). A better understanding of cognitive strategies (i.e., the ways in which people access and recall information) used during the recall process could help to design survey questions and interview procedures--and improve recall. These strategies, however, are not well understood, especially in older population groups. Recent information suggests that adults age 18 to 65 use various cognitive strategies when recalling portion sizes of foods eaten the previous day (Chambers, Godwin, & Vecchio, 2000). Understanding the cognitive strategies for estimating portion size is important information to have when developing effective estimation methods for procedures such as the 24-hour dietary recall, a technique used in many nutrition studies. Currently, there is little information about the cognitive strategies used by the elderly and how accurately they estimate portion sizes.
It is unclear whether using aids to help respondents estimate portion sizes increases accuracy for the elderly. Although these aids have the potential to provide an accurate, convenient means of estimating food portions, some research has indicated the accuracy of estimations may not improve with certain foods when aids are used (Godwin et al., 2001). The purpose of this research, therefore, was to gain a better understanding of the process that elderly respondents use to estimate portion sizes and to determine if aids used to estimate portion sizes improve these respondents' accuracy in saying how much they had eaten.
Methods
Phase I
Four highly trained interviewers conducted one-on-one interviews with 118 respondents age 65 years or older. Respondents were recruited from existing consumer-testing databases; by referral from associates; and through advertisements posted in health departments, churches, schools, and businesses. Of the 118 respondents, 75 percent were women; 65 percent were White, 32 percent were Black, and 3 percent were of other racial origins.
Because strategies for estimating portion size could be affected by the aids shown to participants, four sets of aids were used, with about 30 respondents assigned to each specific set. The aids represented various 2- and 3-dimensional aids for estimating portion sizes that have been used in the CSFII and NHANES studies as well as new aids that have been available to nutritionists, such as a book of photographs of portion sizes (Hess, 1997). The first set consisted primarily of 2-dimensional aids in a booklet that included full-size drawings of bowls, cups, plates, and glasses; three diagrams of geometric shapes--a muffin-shaped grid, cylindrical diagram, and circles; and a tool for estimating portions of wedges. Actual measuring cups and spoons and a ruler also were included.
The second set included mostly 3-dimensional aids such as actual bowls, cups, plates, glasses, measuring cups and spoons, bean bags in four sizes, a ruler, and sticks for estimating thickness. Also included in...
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