Factor-of-risk (Φ) for vertebral fracture is the ratio of applied load to vertebral strength. Obese subjects had higher Φ for standing and lifting compared to lean controls and women with anorexia nervosa. In contrast, women with anorexia nervosa had higher Φ for bending than lean and obese women. Obese subjects and women with anorexia nervosa had higher Φ for holding compared to lean controls. Results are reported as means +/− SEM. *p<0.03; AN, anorexia nervosa; C, lean controls; OB, obese; Φ, factor-of-risk