There is a confirmed and ongoing need to encourage adherence to healthy dietary patterns in the general population in western societies, given their recognized positive impact in preventing non-communicable diseases (NCDs). A potentially very effective solution is the use of digital tools such as apps and web apps, which can reach a large number of people quickly. Still, to be effective, it is necessary to better understand how participant engagement in these interventions works, to identify the motivations that may lead them to drop out, and to evaluate the effectiveness of these interventions. In our study, an innovative web app designed to encourage adherence to the Mediterranean diet (EATMED) was tested in an intervention study, evaluating adherence to the Mediterranean diet before and after the use of the web app in a cohort of people, compared to a control group, using the MEDI-lite questionnaire. The Health and Taste Attitude Scale questionnaire was also administered to all participants to assess interest in healthy foods and diets, as well as attitudes toward food. The study showed that the score of the Food as Reward subscale of the HTAS had a significant effect on dropout from the intervention study, and that the use of the app among participants who remained resulted in a two-point increase in adherence to the Mediterranean diet, according to the MEDI-lite questionnaire. These results indicate the effectiveness of the EATMED tool and provide useful insights into how to understand and mitigate dropout in digital nutrition interventions.

Background/Objectives: Menu calorie labeling policies aim to promote healthier eating habits, yet their effectiveness remains debated. The present study aimed to evaluate the effectiveness of two alternative qualitative labeling strategies—Physical Activity Calorie Equivalent (PACE) labels and Percent Daily Intake (PDI) pie charts—compared to the standard numeric calorie count mandated in several countries, since they have been proposed to enhance consumer comprehension and decision-making. Methods: A nationwide online survey elicited responses from N = 885 individuals living in Italy. Survey participants were randomly assigned to one of three menu conditions: (1) numeric calorie labeling only, (2) numeric calories plus PACE labels, or (3) numeric calories plus a PDI pie chart. Participants selected a three-course meal from their respective menus. Data on sociodemographic factors, dietary habits, BMI, self-assessed nutritional knowledge, and psychological traits—restrained eating (DEBQ-R) and impulsivity (SUPPS-P)—were collected. Ordinal logistic regressions assessed the impact of labeling format, gender, and nutritional knowledge on total calories ordered. Results: Neither PACE labels nor PDI pie charts significantly influenced total calorie selection compared to numeric calorie labels alone. No significant interactions emerged between labeling format and gender or nutritional knowledge. However, age, BMI, and dietary habits were strongly associated with calorie choices: older adults, individuals with restrictive diets, and those with higher restrained eating scores selected lower-calorie meals, while participants with higher BMI or frequent meat intake opted for more calorie-dense options. Conclusions: Alternative calorie labeling formats alone may be insufficient to alter food choices in online settings. Future interventions should integrate motivational and educational strategies tailored to individual traits and dietary habits, rather than relying solely on calorie presentation format.

There is a confirmed and ongoing need to encourage adherence to the Mediterranean diet in the general population in western societies, given its recognized positive impact in preventing non-communicable diseases (NCDs). A potentially very effective solution is the use of digital tools such as apps and web apps, which can reach a large number of people quickly. Still, to be effective, it is necessary to better understand how participant engagement in these interventions works, to identify the motivations that may lead them to drop out, and to evaluate the effectiveness of these interventions. In our study, an innovative web app designed to encourage adherence to the Mediterranean diet (EATMED) was tested in an intervention study, evaluating adherence to the Mediterranean diet before and after the use of the web app in a cohort of people, compared to a control group, using the MEDI-lite questionnaire. The Health and Taste Attitude Scale questionnaire was also administered to all participants to assess interest in healthy foods and diets, as well as attitudes toward food. The study showed that the score of the Food as Reward subscale of the HTAS had a significant effect on dropout from the intervention study, and that the use of the app among participants who remained resulted in a two-point increase in adherence to the Mediterranean diet, according to the MEDI-lite questionnaire. These results indicate the effectiveness of the EATMED tool and provide useful insights into how to understand and mitigate dropout in digital nutrition interventions.