Investigating cognitive biases: Does halo effect from nutrition or health claims drive negative calorie illusion in food combinations?

People in developed countries have access to healthier food options. However, there is also an increasing availability of energy-dense foods. While energy-dense foods play a major role in food accessibility, their prevalence also escalates the obesogenic environment. This paper aims to understand the role of cognitive biases on food consumption from the view of calorie underestimation. Specifically, the study examines how consumers perceive food calorie content and how consumers interpret the claims on food packaging. 525 UK respondents were asked to evaluate five different food combinations. The average calorie estimations for each meal were compared with their actual calorie contents to identify underestimation/overestimation. T-test was conducted, and logistic regression and linear regression were estimated. The results show that heuristic is often adopted in food selection. Foods are categorised into vice and virtue according to the different goals they support. The existence of virtue food options (e.g., fruit and vegetable) reduces the perceived calorie content of the meal. Likewise, nutrition and health claims such as low-fat and zero-sugar also decrease the calorie estimation, especially when the labelled food is unhealthy. Considering overeating is a consequence of calorie underestimation, consumers' knowledge of nutritional quality needs to be improved.