Background In the UK, there has been rapid growth in the use of online food delivery services, particularly in the out-of-home sector. To enable consumers to make healthier out-of-home purchases, policymakers have recently implemented mandatory calorie labelling including on digital food delivery platforms, but this only applies to large businesses (250+ employees). Post implementation of this policy, this study investigates the prevalence of restaurant calorie labelling in one of the largest online food delivery platforms and whether this is patterned by deprivation.

Methods Web-scraped data for June 2022 and 2023 derived from a major online food delivery service were used to determine the number and percentage of all restaurants displaying calorie labelling delivering to neighbourhoods (LSOAs) in England and Wales (n=28,085, 80.8%). Average calorie content of dishes available (excluding drinks and condiments) was also determined. Associations between area deprivation (LSOA Townsend Score) and (i) the percentage of online restaurants displaying calories and (ii) the average energy content of restaurant dishes were assessed.

Results In 2022 the median number of delivering restaurants per LSOA was 173, of which 13.1% displayed calories with a median energy value of 675 kcal per dish. In 2023 the median number was 205, with 12.6% displaying calories and with a median energy content of 628 kcal per dish. The total number of delivering restaurants per LSOA was positively associated with area deprivation (p<0.001, both years). However, the percentage of restaurants displaying calories was negatively associated with area deprivation, with the median percentage of restaurants displaying calories higher in the most affluent (2022: 17.0%; 2023: 16.0%) compared to the most deprived LSOAs (2022 and 2023: 8.4%; p<0.001, both years). This pattern remained when stratifying by urban-rural status but was less pronounced in rural LSOAs. Overall calories decreased by 7.9% between 2022 and 2023 (95%CI: 7.8 to 8.1; p<0.001). Minimal differences in average energy content of dishes with displayed calories between the most and least deprived areas (15 kcal; p<0.001) were observed.

Discussion In the context of mandatory calorie labelling for larger food businesses, the overall proportion of restaurants displaying calorie information remained low. More deprived areas had a lower percentage of restaurants displaying calorie information compared to more affluent areas, even though the absolute number of restaurants was higher. This suggests that mandatory calorie labelling policy is currently poorly targeted as it only affects a small proportion of restaurants, particularly in more deprived areas.