The use of a wearable camera to capture and categorise the environmental and social context of self-identified eating episodes.

Research investigating the influence of the environmental and social factors on eating behaviours in free-living settings is limited. This study investigates the utility of using wearable camera images to assess the context of eating episodes. Adult participants (N = 40) wore a SenseCam wearable camera for 4 days (including 1 familiarisation day) over a 15-day period in free-living conditions, and had their diet assessed using three image-assisted multiple-pass 24-hour dietary recalls. The images of participants' eating episodes were analysed and annotated according to their environmental and social contexts; including eating location, external environment (indoor/outdoor), physical position, social interaction, and viewing media screens. Data for 107 days were used, with a total of 742 eating episodes considered for annotation. Twenty nine per cent (214/742) of the episodes could not be categorised due to absent images (12%, n = 85), dark/blurry images (8%, n = 58), camera not worn (7%, n = 54) and for mixed reasons (2%, n = 17). Most eating episodes were at home (59%) and indoors (91%). Meals at food retailers were 24.8 minutes longer (95% CI: 13.4 to 36.2) and were higher in energy (mean difference = 1196 kJ 95% CI: 242, 2149) than at home. Most episodes were seated at tables (27%) or sofas (26%), but eating standing (19%) or at desks (18%) were common. Social interaction was evident for 45% of episodes and media screens were viewed during 55% of episodes. Meals at home watching television were 3.1 minutes longer (95% CI: -0.6 to 6.7) and higher in energy intake than when no screen was viewed (543 kJ 95% CI: -32 to 1120). The environmental and social context that surrounds eating and dietary behaviours can be assessed using wearable camera images.