Poster Topical Area: Nutritional Epidemiology

Location: Hall D

Poster Board Number: 740

E05-01 - Formative Evaluation of Pictorial Methods for Portion Size Estimation in Malawi

Sunday, Jun 10
8:00 AM – 6:00 PM

Abstract Category: Nutritional Epidemiology – Innovation and Validation of Detiary Assessment Tools and Their Applications

Keywords: Dietary assessment tools, portion size estimation, pictorial literacy, low-resource settings

Objectives: Current dietary recall methods used in low-resource settings are prone to errors in portion size estimation. This study investigated the preference for, ease of use perceptions, and accuracy of visual variables in portion size estimation aids (PSEAs) for dietary recall in Malawi. Visual variables tested included food shapes versus photos, number of portion size options, photo angle, and simultaneous versus sequential portion size image presentation.

Ninety-six women 18-45 years of age served themselves portions of five foods (groundnuts, bananas, nsima, bean relish, vegetable relish) and water, which were weighed before and after consumption. We administered a meal recall using a digital or printed PSEA thirty minutes after eating and assessed participants' preferences for and ease of use perceptions of the PSEAs through a structured interview. Across participants and foods, we calculated the percentage of PSEA selections within 20% of the actual gram weight of food or water consumed.

Participant preference and ease of use perceptions favored photos, 45-degree photo angle, and simultaneous presentation. Three and five portion sizes had similar preference and ease of use perceptions, but three portions were slightly more accurate than five (28% versus 25% within 20% of actual gram weight). A 45-degree versus 90-degree photo angle was more accurate (35% versus 25%), as was a simultaneous versus sequential presentation of images (41% vs. 31%). Accuracy was similar for other visual variables. Differences in preference and ease of use perceptions between digital and printed PSEAs were inconclusive, but will be further tested in an upcoming validation study.

Results indicate PSEA visual variables can be optimized to improve participants' experiences during and enhance accuracy of dietary recalls. Results of this formative evaluation and the planned validation study can inform the development of PSEAs for dietary intake data in low-resource settings.

Funding Source: RTI International
Photos, 3 portion sizes, beans relish

Photos, 5 portion sizes, beans relish

Shapes, 3 with in-between portion sizes, beans relish

Shapes, 5 portion sizes, beans relish

CoAuthors: Chrissie Thakwalakwa Kantukule, PhD – Chancellor College, University of Malawi; Mary Muth, PhD – RTI International; John Phuka, PhD, MBBS – College of Medicine, University of Malawi; Jennifer Coates, PhD – Tufts University; Beatrice Rogers, PhD – Tufts University; Brooke Colaiezzi, MS – Tufts University; Winnie Bell, MS, MPH, PhD candidate – Tufts University; Valerie Flax, PhD, MPH – RTI International

Courtney H. Schnefke

Research Public Health Analyst
RTI International
Research Triangle Park, North Carolina