Biopsychological examination of changes in food reward during weight loss in women

Background: While taste is a main driver of food choice, food reward is more than just the sensation of taste and interacts with the homeostatic system (e.g. hunger) to create pleasure (liking) and motivation (wanting) for food. Food reward is a driver of food intake and therefore commonly thought to be related to obesity. However, liking/wanting have never been targeted to improve weight management strategies. Objectives: This thesis aims to explore the role of food reward during 1) weight management, 2) weight loss (WL) and no-contact follow-up, and 3) its association with appetite control and obesity in women. Methods: Food reward and appetite-related variables (e.g. body composition, energy intake, eating behaviour traits) were investigated during a controlled-feeding WL, 1-year follow-up and a cross-sectional analysis between women with or without overweight/obesity. Liking and implicit wanting were assessed with the Leeds Food Preference Questionnaire. Results: Contrary to expectations, a systematic review showed that liking and wanting decreased after different weight management interventions. The diet intervention added that liking decreased for all food categories independently from diet modality or improvement in appetite control. After 1-year of no-contact, weight was regained, appetite control weakened and liking returned to baseline levels. Lastly, women with overweight/obesity did not have higher wanting for high-fat sweet but lower wanting for low-fat sweet food compared to women within the normal range of BMI. Importantly, wanting for low-fat food was associated with improved appetite control and less fat mass while it was the contrary for high-fat food. Conclusions: The role of food reward in weight management distinguishes between liking and wanting and high-fat vs low-fat, as its components dissociated during WL and had opposite impact on appetite control. Food reward does not differ greatly between women with or without overweight/obesity and other appetite-related factors are needed to understand obesity status.