Accuracy of dietary intake assessments using food records based on photographic images captured by visually impaired people

Abstract

Traditional methods to assess dietary intake have limited and questionable application in visually impaired people since the lack of vision and low leading role in their diet make it difficult to quantify and detail the food consumed throughout the day. Thus, this study investigated whether it is possible to accurately identify foods and estimate their quantities using food records based on photographic images captured by visually impaired people. A panel of experts composed of nutritionists (n = 20) assessed these records comprising three standardized meals (breakfast; lunch/dinner; snack) from visually impaired people (n = 40) using two different protocols (frontal photo; aerial photo). Each nutritionist reported an estimated food record for each photographic image, which was compared to its respective weighed food record. For both frontal and aerial photos, experts were frequently correct for the number of food items in the meal (95.0% or over for breakfast, 100% for lunch/dinner, and 100% for snacks). All experts identified at least 11 of the 13 food items, but the majority correctly estimated the food amount only for 23% of the items. Compared to the weighed food record, the photographic records underestimated the amount of 61.5% of food items based on frontal photos, and of 76.9% of food items based on aerial photos. While most foods could be identified by photographic images captured by visually impaired people enabling a qualitative assessment of the diet, they could not be quantified accurately by nutritionists.