Stay the course: determining predictors of lapse and relapse in weight loss maintenance behaviors

Overweight and obesity have emerged as a growing public health concern, with global rates steadily rising over the past decades. In the Netherlands, 50% of the adult population are overweight, with 14% classified as obese. This is problematic as being overweight is associated with an increased risk of various non-communicable diseases, such as cardiovascular diseases, diabetes, musculoskeletal disorders, and several cancers. While losing weight offers numerous health benefits for individuals who are overweight or obese, maintaining weight loss is often challenging. Understanding the predictors of lapse and subsequent relapse is crucial for preventing or minimizing their occurrence in weight loss maintenance behaviors. Therefore, the overall aim of this thesis is to determine the predictors of lapse and relapse in weight loss maintenance behaviors, in specific physical activity and dietary behavior. This thesis demonstrates that there are several predictors that show promise in predicting lapse and relapse, both at the individual level and within the environmental context. Across the studies, self-efficacy consistently emerged as a significant predictor, emphasizing its pivotal role in behavior change and relapse prevention. Additionally, the environment, encompassing both the physical and social environment, played a significant role. Particularly social pressure and social norms were key factors within the social environment. Our findings underscore the multifaceted nature of predictors of lapse and relapse in physical activity and dietary behavior. This highlights the importance of addressing both individual and environmental factors for health practitioners guiding individuals toward sustainable lifestyle changes, and in interventions aimed at behavior change maintenance. Furthermore, to enhance lifestyle coaching, health practitioners need to be mindful that their perceptions of primary predictors of relapse in physical activity and dietary behavior might not fully align with those of individuals who have experienced relapse. Moving forward, achieving consensus on operational definitions of lapse and relapse in physical activity and dietary behavior is of importance to advance future research in this field.