The importance of field experiments in testing of sensors for dietary assessment and eating behavior monitoring.

The field of sensor-based dietary assessment and behavioral monitoring is rapidly expanding. New devices and methods for detection for food intake and characterization of ingestive behavior, energy intake and nutrition have been introduced. Quite often the testing of new devices is limited to restricted meals in laboratory setting, which has the advantage of being controlled, but may not be representative of real life conditions. To illustrate the importance of field testing, we performed a statistical comparison of meal microstructure metrics acquired in laboratory versus a field-like study. In the laboratory study, individual participants ate a self-selected meal in isolation. In the field-like study, participants consumed selfselected meals in a social setting. In both studies, the participants were monitored by both video observation and wearable food intake sensors. Statistically significant differences were observed in the duration of the meals, duration of ingestion, number of bouts of ingestion, duration of pauses between ingestive bouts, number of bites and other metrics. These results suggest that field testing presents a far different picture of ingestion process and therefore is needed for any realistic assessment of the monitoring devices.