This thesis is a qualitative investigation of the factors which maintain anorexia nervosa (AN) according to the transdiagnostic theory of eating disorders (Fairburn et al., 2003). AN is difficult to treat and continues to evade complete understanding. The present study aimed to promote further understanding of food restriction and physical activity in relation to the constructs of clinical perfectionism, core low self-esteem, mood intolerance, and interpersonal difficulties. Twenty females with self-reported AN were recruited from Guelph, Ontario and participated in semi-structured interviews. Thematic analysis revealed eight major themes for clinical perfectionism, five for core low self-esteem, five for mood intolerance, and six for interpersonal difficulties. The in-depth emotional accounts and details of food restriction and physical activity in relation to the four constructs examined in this study may contribute to further appreciation of AN, informing practitioners and family members, promoting empathy, and improving treatment options.