Food retail outlets, by making food accessible, available and affordable, contribute significantly to consumers’ food choices, including snack food choices, and ultimately their longer-term health status. Therefore, the food retail environment may represent an opportune place to harness marketing power to implement anti-obesity measures. The study aimed to understand consumers’ purchasing decisions for confectionery and savoury snack food items both on and off promotion. Associated objectives sought to identify what influences consumers’ food buying decisions and understand if these differ by food product category or promotional status, particularly in respect of single versus multi-pack confectionery/savoury snack food items, to inform retail promotional strategies and anti-obesity policymaking. In order to gain an insight into consumers’ motivations, attitudes and behaviours, an ethically compliant, quantitative survey was designed which collected data from 302 respondents aged 18-75. Three-quarters (76%) of those surveyed believed promotions are more prevalent for less healthy foods compared to healthy foods. Promotions were found to have a significant impact on consumer behaviour, causing 64% to purchase greater volume of an item and 76.5% to purchase confectionery and savoury snacks more readily. Respondents made unintended purchases regularly with the highest incidence among those shopping four to six times per week, while 72% of all unintended purchases were attributed to promotional activity. Findings highlight the clear effect promotions have on consumers’ buying behaviour. The main enabler reported to encourage consumers to make healthier food choices was “if healthy food was cheaper”. Additionally, the findings also suggest that increasing the price of less healthy foods (such as confectionery and savoury snacks) could also impact positively on consumers’ purchasing behaviours. The research indicates the potential for future supermarket health promotion initiatives to encourage consumers to make healthier food choices which could play a vital role in improving public health and subsequently reduce obesity levels.