Gender differences in the impact of weight-related stigmatisation on self-determined motivation and physical activity in individuals with overweight and obesity

Stigmatisation based on an individual’s weight remains a prevalent occurrence across the world. This form of stigma has been shown to impact psychological, behavioural, motivational and physiological domains for not only individuals with overweight and obesity, but also those within the normal weight ranges. Despite impacting individuals across all weight ranges, weight-related stigma appears particularly salient for those with overweight and obesity with evidence that rates of stigma increase as weight status increases. It is well established that having overweight or obesity increases an individual’s risk for a variety of medical conditions that impact quality of life and morbidity. However, many of these conditions are preventable through key factors such as physical activity and diet. High rates of physical activity play a role in weight reduction, and are particularly crucial in the maintenance of weight loss. Further, physical activity has established benefits for broader physical health and wellbeing irrespective of weight status. While a direct relationship between weight-stigma experiences and physical activity has not consistently been found, relationships between weight-stigma and different forms of motivation regarding exercise, as well as between motivation and physical activity have been demonstrated in the research. If it is possible that there is a relationship between weight-stigma and motivation for exercise, which in turn can impact levels of physical activity, then it is important to explore whether this potential indirect relationship could be playing a role in reducing levels of physical activity in individuals with overweight and obesity. If this is the case, then weight-related stigma may present an additional target variable in the treatment of overweight and obesity. The body of research exploring weight-related stigma, including prevalence and negative impacts, has been growing steadily over the last two decades. However, despite this increase in research very few studies have explored the relationship between weight-related stigma, motivation for exercise, and level of physical activity. To our knowledge no research to date has explored this relationship using longitudinal data. Further, a large amount of the existing research literature utilises female-only or female-majority samples, which has limited the ability to explore whether females and males are differentially affected by weight-related stigma. This thesis aimed to address these limitations in the existing literature by exploring the relationship between weight-related stigma, self-determined motivation, and physical activity across genders utilising both cross-sectional and longitudinal data.