The impact of restricting price promotions on foods high in fat, sugar and salt on purchasing behaviours: a randomised controlled trial in a simulated online supermarket in the UK.

Unhealthy diets, including those high in saturated fats, added sugars and Na, are a leading risk factor for non-communicable diseases including CVD, type 2 diabetes, some cancers, as well as development of overweight and obesity. Globally, in 2015, overweight and obesity contributed to 4 million deaths and 120 million disability-adjusted life years. When making food purchasing decisions, consumers rely on a range of information sources to determine the nutritional content and suitability of products to meet their requirements and preferences. These can include nutritional information panels, descriptions from packaging or menus and claims made by food manufacturers. However, food industry marketing tactics can often misinform consumers. The accurate presentation of nutritional information can influence consumer perceptions and choices, particularly when health-related claims are used. Increasingly, consumers are purchasing food and drinks from online food delivery (OFD) platforms. These platforms provide consumers with a convenient way to order meals from fast-food outlets, restaurants and cafes, as well as items from convenience stores and supermarkets. An analysis of meals purchased away from home in five countries between 2018 and 2021 found that while the overall number of meals purchased out-of-home remained consistent, the proportion ordered using an OFD platform almost doubled. Additionally, analysis of nationally representative survey data found that 34 % of Australians reported using an OFD platform to order meals in the previous 30 d. Other recent studies have shown that the majority of foods available on OFD platforms are unhealthy, and that unhealthy food outlets are more common in areas of socio-economic disadvantage and regional areas (population centres outside major metropolitan areas). Despite this, OFD platforms often use an unregulated ‘healthy’ category label for food outlets within their apps. However, there is limited evidence regarding the validity of these classifications and whether they support or hinder informed consumer choice and public health nutrition efforts. This study aimed to examine how a leading OFD platform classifies ‘healthy’ food outlets in Australia compared to classification by expert-informed proxy tools for assessing the healthiness of online food outlets.