Low body mass index is associated with higher rates of mild cognitive impairment and worse memory performance among older Canadian adults: An analysis of the Canadian Longitudinal Study on Aging (CLSA

Consumption of food that is high in fat, salt and/or sugar (HFSS) is a known contributor to poor diet, obesity and associated non-communicable diseases. To target these items, the UK government introduced legislation restricting the promotion, placement and advertisement of HFSS items. Since 2022, HFSS items cannot be placed in prominent locations in stores, including within two metres of checkouts or queuing areas, at the end of aisles, at the store entrance or equivalent places online. Other restrictions on HFSS items, such as restrictions of volume price promotions (e.g. multi-buy offers), came into force in 2025 and a ban on TV advertising before 21.00 or paid-for online advertising in 2026. Price promotions, i.e. making temporary changes to the price of foods and beverages, are used to market food to consumers, to stimulate sales and consumption. Among the different types of price promotions, temporary price reductions (TPR: short-term price reductions such as ‘50p off’ or ‘25 % lower price’) are the most common price promotion in the UK, with foods and beverages high in sugar more likely to get promoted and receive higher discounts. A Public Health England analysis on the role of price promotions in household purchases of food and drinks reported that 18 % of take-home food and drink purchases can be considered incremental as a result of price promotions, with TPR contributing to 24 % of overall spend on take home food and drink in the UK in 2015. Similarly, an analysis of retail purchase and price promotions in Scotland reported that in 2016 TPR accounted for 26 % of total calories purchased for take-home food and beverages, and that unhealthy food and drinks were more likely to be purchased while on promotion. However, such promotions on HFSS products were not within the scope of the regulations on promotions in 2025, despite the evidence that price promotion, especially TPR, significantly increases sales of HFSS foods due to both its widespread application and impact on purchasing behaviours. It is unclear whether TPR restrictions would be an effective public health policy. Although there is robust evidence that price promotions on unhealthy foods can increase sales, which could then lead to consumption of such foods, there is no direct evidence addressing whether restricting price promotions on unhealthy foods could reduce consumption. However, a later study in a simulated online supermarket explored the effects of restricting TPR on HFSS foods completely on purchasing behaviours, reporting 10 % less total energy selected in shopping baskets following the removal of TPR. This suggests that restricting TPR on HFSS foods has the potential to influence consumer behaviours, albeit with further studies needed to investigate the robustness of this effect. However, concerns have also been raised regarding whether restricting TPR could impact on the cost of living. There is evidence that price promotions can deliver significant savings for households, thus a policy restricting TPR might have implications for food affordability, potentially generating public and/or political backlash. Therefore, it is also important to explore alternative options that might be similarly effective, yet more acceptable. One option might be to allow price promotions on HFSS foods, but restrict the communication of these promotions to consumers (e.g. restricting the signage that alerts the consumers to the reduced price). To our knowledge, there is currently no evidence of the impact of exclusively restricting communications regarding price promotions, without restricting the price promotion itself, on purchasing behaviours. Thus, in this study, we investigated the potential impact of restricting communication of TPR on HFSS items, on food purchasing behaviour. We also investigated the impact of restricting TPR entirely. Specifically, this study set out to investigate: