Subjects’ Perception in Quantifying Printed and Digital Photos of Food Portions

Abstract

Although digital photos have the potential to improve the precision of reported portions in dietary assessment, there are few studies investigating its accuracy in comparison to printed photos. The aim of this study was to evaluate the perception of adults in quantifying food portion sizes using printed and digital photos, displayed on computer-screens and tablets. In total, 1165 evaluations were performed for 60 photos of portion sizes in Brazil. Each participant (n = 58) attended two sessions in the study center, with an interval of at least one week. In each session, twelve food portions were prepared and randomly evaluated by each participant in its printed and digital forms. The mean error (difference between the estimated and true portions) was not significantly different between the printed photos (2.1 g ± 47.2) and the digital ones (−6.4 g ± 53.7). The agreement on using the printed and digital photos was 91% and 90%, respectively. Furthermore, the use of the tablet was more prone to underestimation when compared to printed and computer-screen photos (p < 0.001). Overall, participants did not present major difficulties in perceiving the portion sizes using the printed and digital photos, but the use of tablets led to less accurate results, indicating that this needs to be further evaluated.

Validation of a digitally displayed photographic food portion-size estimation aid among women in urban and rural Malawi

“…We found that our digitally displayed PSEA did not have sufficient accuracy to be scaled up in Malawi in their current form. This finding is consistent with recent results from Brazil showing that digital PSEA displayed on a tablet led to more underestimation than other methods (19) . However, given that these are the first studies in LMIC to validate digitally displayed photographic PSEA, we expect that future studies could refine digital PSEA to improve accuracy for estimating usual individual intakes or intake of specific nutrients and for measuring differences in intakes between groups.…”

“…Although our study had some limitations, digitally displayed photographic PSEA could be improved with further testing and the advantages and disadvantages of using different types of PSEA should be considered. Our findings showed that digitally displayed and print photographic PSEA were comparable, which is consistent with findings from two studies in the USA (35,36) and one from Brazil (19) . This indicates that even in a setting with low media exposure, digitally displayed PSEA can be used interchangeably with printed food atlases of the same dimensions, provided the accuracy of the PSEA is adequate.…”

“…Most published validation studies of PSEA to date have been carried out in high-income countries with high literacy rates (12) . Only eight validation studies have been conducted with adults in low-and middle-income countries (LMIC) (7,(13)(14)(15)(16)(17)(18)(19) . Two of these used life-size printed photographs as PSEA (14,18) , four used smaller-than-life-size printed photographs (13,(15)(16)(17) , and one used smallerthan-life-size printed photographs and digital photographs taken by the participants themselves as a memory aid (7) .…”

“…Two of these used life-size printed photographs as PSEA (14,18) , four used smaller-than-life-size printed photographs (13,(15)(16)(17) , and one used smallerthan-life-size printed photographs and digital photographs taken by the participants themselves as a memory aid (7) . A recent study in Brazil, a middle-income country, compared digitally displayed and printed photographic PSEA in a small sample of adults (19) . To date, there are no studies with adults in low-income countries that assessed the validity of a digitally displayed photographic PSEA or that included more than one type of PSEA for comparison.…”

Perspectives from individuals with low education and interviewers using the GloboDiet 24 h recall: a qualitative study

“…In Brazil, an adapted version of the software together with a photograph manual for food portion sizes is available (7) . Nonetheless, when we assessed the ability of individuals to quantify some of those photographs, we noticed larger errors among low-educated individuals compared with other population groups (8) . Although individuals are cognoscenti (9) and education level is usually considered not to be a limiting factor for the R24h (10) , the level of education seemed to influence the ability of those interviewed to inform their food intake.…”