Accuracy of applications to monitor food intake: Evaluation by comparison with 3-d food diary

Objective: The availability of nutrition applications (apps) has increased in recent years. The aim of this study was to assess the accuracy of nutrient intake calculations from some of the leading apps. Methods: We identified five apps according to some selection criteria: >4-star ratings, >1 million downloads, including a food composition database, and in Italian language. Apps were used for 2 wk each. Using a 3-d food diary, the nutritional values obtained from each app were compared to a reference method including the Food Composition Database for Epidemiologic Studies in Italy. Energy intake differences were calculated for single nutrient and 3-d food diary between single app and reference method after food-item matching. Bland–Altman plots were used to assess agreement of the methods. Results: Apps identified were FatSecret, Lifesum, MyFitnessPal, Yazio, and Melarossa. Apps tended to underestimate total energy intake compared with the reference method, from a minimum of –2 kcal for Lifesum, to a maximum of –5.4 kcal for Yazio (average per item). Apps tended to underestimate lipids, and to a lesser extent carbohydrate and fiber intake, except for Yazio and Lifesum, which overestimated the intake of protein. These discrepancies appear to be due to the use of no country-specific food composition databases and to user customization of the food list. Conclusions: The present findings suggest that the leading nutrition apps present critical issues in assessing the intake of energy and nutrients. Implementation of a framework for quality assessment is necessary to drive the design and development of higher-quality apps. Further research on efficacy and use of apps to monitor food intake is also warranted and some recommendations are provided.