Strengths and Limitations
OFD, OFD behaviors
EVENTS, EMA
To the best of our knowledge, this is the first study to use EMA to capture OFD behaviors and context in near real time. Real-time monitoring is critical to ensuring ecological validity and is a major advantage of the EMA methodology, given the sporadic nature of OFD use. Moreover, this study gathered data on the use of OFD that is independent of market research or company reports and is an important addition to the public health literature that currently lacks evidence on the consumption of OFD.However, several limitations of this study must also be acknowledged. This was a pilot study where 2 varying EMA protocols were tested for their feasibility and acceptability. Hence, caution is warranted when interpreting the associations found in this study between demographics, lifestyle risk factors, and OFD events. In addition, this study has yet to validate the capture of OFD consumption against gold standard dietary assessment methods such as the 24-hour recall. An important next step would be to examine the percentage match for each occasion of OFD consumption between a 24-hour recall and the EMA protocol.All data gathered and analyzed in this study were self-reported by the participants, which is inherently prone to response bias. Furthermore, the EMA app used in this study was limited to iOS or Android users and appeared to cause more issues with Android users. Owing to convenience sampling, the study sample was highly educated females residing in areas of high socioeconomic advantage, which accordingly may limit the generalizability of the findings.In addition, it is noted that the monitoring period of 7 days may not have adequately or accurately captured OFD events, as more than half of the study sample reportedly used OFD services 1 to 2 times a month. Future studies could use the event-contingent sampling approach and potentially extend the monitoring period to 14 days instead, alongside incorporating end-of-day reminders.Moreover, although a training guide was provided online to participants, the study would also benefit from an in-person training day, as recommended by previous EMA studies [