RESUMO
Online systems that allow employees to pre-order their lunch may help reduce energy intake. We investigated the acceptability of a pre-ordering website for a workplace canteen that prompts customers to swap to lower-energy swaps and the factors influencing swap acceptance. Employees (n = 30) placed a hypothetical lunch order through a pre-ordering website designed for their canteen while thinking aloud. Semi-structured interview questions supported data collection. Data were analysed using thematic analysis. Acceptability was generally high, but potentially context dependent. Practical considerations, such as reminders to pre-order, user-friendliness, provision of images of menu items and energy information while browsing, an ability to reserve pre-ordered meals, and a swift collection service facilitated acceptability. The restrictive timeframe within which orders could be placed, a lack of opportunity to see foods before ordering, and prompts to swap being perceived as threatening autonomy were barriers to acceptability. Swap acceptance was facilitated by the provision of physical activity calorie equivalents (PACE) information, and swap similarity in terms of taste, texture, and expected satiety as well as the perception that alternatives provided meaningful energy savings. Online canteen pre-ordering systems that prompt lower-energy swaps may be an acceptable approach to help reduce energy intake in the workplace.