The same, only different: Smartphone-based dietary Ecological Momentary Assessment tools vary in complexity, usability and active information processing.

OBJECTIVES

Ecological Momentary Assessment (EMA) is popular for assessing dietary intake in real life and real time. Available tools differ substantially in the type and number of implemented features, including features to assess what and how much was consumed. These features require qualitatively different input that might have a differential impact on the participants' cognitions and behaviours while taking part in the study. This study aimed to test whether more complex dietary assessment tools, indicated by the type and number of assessment features, induce more active information processing (AIP).

DESIGN

Preregistered online between-subjects experimental study.

METHODS

A total of 373 participants (65.4% female; mean age 30.4 years) were randomly allocated to view one of eight EMA protocol mock-ups, each describing a food tracking process verbally and using screenshots. Afterwards, they rated the protocol in terms of its complexity (manipulation check), AIP and its potential impact on eating-related cognitions, intentions and eating behaviour change.

RESULTS

The eight EMA protocols differed in perceived complexity, that is protocols with more tracking features were perceived as more complex compared to those with fewer tracking features. EMA protocols that were perceived to be more complex were also perceived to induce more AIP. However, there were no differences in perceived impact on eating-related cognitions, intentions and behaviour.

CONCLUSIONS

Differences in complexity and usability may influence compliance and study results. Researchers thus need to carefully select the appropriate EMA protocol for their study to balance the need for collected information with the need for high compliance.

© 2026 The Author(s). British Journal of Health Psychology published by John Wiley & Sons Ltd on behalf of British Psychological Society.