Eating with eyes - Comparing eye movements and food choices between overweight and lean individuals in a real-life buffet setting

Researchers have long sought to pinpoint factors underpinning individual differences in eating behaviour. Emerging data from eye-tracking studies have suggested that attentional biases to food exist among individuals and food types. However, such studies have thus far relied on food images and computerised tasks, limiting real-world implications. The present study tested 32 healthy male participants (16 being overweight) for attentional biases in an ad libitum buffet setting, using wearable eye-trackers. The eye-tracking analyses suggested that sugar content moderated visual fixation biases (p < 0.05), whereas BMI exerted significant effects on pupil diameter (p < 0.05). In addition, findings from the study revealed tripartite relationships between eye-tracking, self-reported liking, and ad libitum intake. Although visual fixation in the “view” condition was correlated with liking for high-calorie food, further analyses showed that this measure was not a strong predictor of food selection. Instead, visual fixation during the selection task could be the key predictor for selection of savoury food. In contrast, neither eye-tracking nor self-reported measures could adequately predict selection of desserts, implicating distinct decision-making processes for different types of food. Due to the small sample size, findings from this study should be replicated in future research. Overall, this study highlights the importance of realistic experimental settings in eye-tracking studies for understanding eating behaviour.