Samenvatting

Background & aim Adequate protein intake is essential during recovery from illness to prevent complications such as malnutrition, sarcopenia, and delayed wound healing. Mobile applications may support self-monitoring and early detection of inadequate intake. This study evaluated the concurrent validity of the eiFIT app, a simplified self-monitoring tool based on the Rate-a-Plate method, by comparing its protein intake estimates with a 24-h dietary recall and by assessing its ability to detect inadequate protein intake. Methods This cross-sectional study used data from the Optimal Physical Recovery After Hospitalization (OPRAH) randomized controlled trial, involving patients undergoing major oncologic gastrointestinal and pulmonary surgery. Daily protein intake recorded by the patient with the eiFIT app was compared to a 24-h dietary recall conducted by a dietitian on the same day. Protein intake was categorized as very low (<50 %), low (50–75 %), adequate (75–125 %), or high (>125 %) relative to individual protein requirements. Sensitivity, specificity, and predictive values were calculated for the app in detecting inadequate intake (<75 %). Results In total, 62 patients (mean age 62 ± 11 years; 52 % male) contributed 245 paired days of intake data. The eiFIT app showed a sensitivity of 72 % and specificity of 83 % in identifying inadequate protein intake, with an overall accuracy of 78 %. Misclassification appeared to occur more frequently among overweight or obese individuals and males with higher protein requirements. Conclusions The eiFIT app demonstrates moderate validity in identifying inadequate protein intake among surgical oncology patients and may support early nutritional screening and self-monitoring. Its ease of use makes it suitable for daily application, though refinements in portion estimation and data input may improve accuracy. Further validation in broader clinical populations is warranted.