January 2010

Assessment of the Accuracy of Portion Size Reports Using Computer-Based Food Photographs Aids in the Development of an Automated Self-Administered 24-Hour Recall

Amy F. Subar, PhD, MPH, RD; Jennifer Crafts, PhD; Thea Palmer Zimmerman, MS, RD; Michael Wilson, PhD; Beth Mittl, MS; Noemi G. Islam, MPH; Suzanne McNutt, MS, RD; Nancy Potischman, PhD; Richard Buday, FAIA, Stephen G. Hull, MS; Tom Baranowski, PhD; Patricia M. Guenther, PhD, RD; Gordon Willis, PhD; Ramsay Tapia; Frances E. Thompson, PhD

The goal of the research presented in this article was to assess the accuracy of portion-size estimates and the preferences of the subjects by showing them digital images of foods and food shapes. The researchers wanted to know how best to provide these images as part of an online 24-hour dietary recall known as ASA24 (automated, self-administered 24-hour recall), an Internet-based research tool developed by the NCI, Westat (a research firm), Archimage, Baylor College and the USDA. During the course of 2 studies, subjects selected and ate foods for breakfast and lunch. What they selected was weighed and the amounts recorded. A day later the same subjects used a computer program to select photographs that best represented the portion sizes they had eaten on the first day. Five food categories were used in the studies: amorphous/soft foods, single unit foods, small pieces, spreads and shaped foods. Nine types of food were served.

There were 2 objectives for Study 1. The first used 4 different types of images to assess accuracy of portion sizes: aerial photographs, photos shot at a 45 degree angle, images of household measures like cups and spoons, and images of food mounds. The second objective was to determine participant preference of the way food images were presented on the screen: either simultaneous (all portion size options were presented at once) or sequential (portion sizes were presented one at a time).

In Study 2 the effects of both size and number of portion-size images on the accuracy of estimates was assessed. The subjects were shown either small or large images, and either 4 or 8 images.

Within food categories there was no significant difference in accuracy by method of presentation, although there was better accuracy across groups for simultaneous vs. sequential presentation for amorphous/soft foods and small pieces. Approximately 15% of the overall number of estimates were within 10% of the amount actually consumed. Participants generally preferred the aerial photographs and most indicated a strong preference for simultaneous vs sequential presentation of images. For most foods, 8 vs 4 photos were more accurate, but not significantly so. For photo size there was no significant difference in accuracy of reporting. Overall, accuracy results tended not to be statistically significant in these studies, but the researchers felt that the results confirmed that using various types of images (photographs, mounds, and household measures) in combination (as opposed to just photos) in an ASA24 would be acceptable.

The additional article referenced below describes a study undertaken in West Africa that looked at the efficacy of prenatal micronutrient supplementation on birth outcomes. In it pregnant women were given 2 food items on one day and then, on the next day, asked to choose a photograph (from several in an album) that best represented the amount they ate the previous day. The correct photo was chosen 55% of the time and the researchers concluded that using photos in a 24-hour recall context may be useful.

Continuing Education Article:

Subar, A., Crafts, J., Zimmerman, Thea P., Wilson, M., Mittl, B., Islam, N., McNutt, S., Potischman, N., Buday, R., Hull, S., Baranowski, T., Guenther, P., Willis, G., Tapia, R., Thompson, F. (2010). Assessment of the Accuracy of Portion Size Reports Using Computer-Based Food Photographs Aids in the Development of an Automated Self-Administered 24-Hour Recall. Journal of the American Dietetic Association, 110(1), 55-64.

http://download.journals.elsevierhealth.com/pdfs/journals/0002-8223/PIIS0002822309016836.pdf

Additional Article:

Huybregts, L., Roberfroid, D., Lachat, C., VanCamp, J., Kolsteren, P. (2008) Validity of Photographs for Food Portion Estimation in a rural West African Setting. Public Health Nutrition, 11(6), 581-587.