Participant recruitment and study procedure
OSF, eating disorder
MAY
A convenience sample of university staff and students was recruited through online advertisements and the distribution of physical flyers. An online screener questionnaire excluded participants who did not meet the following criteria: living in Australia, aged between 18–65 years, fluent in English, no current or previous diagnosis of an eating disorder, and who were able to attend an in-person laboratory session.Participants attended the in-person session at a university campus in Sydney (April to May 2022). Instructions were provided upon arrival; participants were requested to complete the online tool individually using a laptop, and following the prompts at the start of each section (based on either food images on computer screen or real foods at food stations) to select the closest match of their perceived portion size norms from the provided options for each test food. All participants were blinded to the aim of the study but were reminded of the definition of portion size as ‘the amount of food they eat at one sitting’. A hard copy of the instructions was provided for participants to keep during the session, informed consent was obtained from all participants. Researchers remained in the laboratory room in an unobstructive manner during the study process.A small token was offered to compensate participants for their time. The study was approved by The University of Sydney Human Research Ethics Committee (ethics approval number 2022/147). Study protocol was registered a priori on the Open Science Framework (OSF registration 10.17605/OSF.IO/X3FM7).Due to the preliminary nature of this study, a power analysis could not be calculated based on previous literature. Thus, a sample size of 100 participants was used as recommended for preliminary validation in dietary assessment [