Background. Breast cancer is often comorbid with overweight and obesity, with approximately
65% of women receiving a cancer diagnosis having a body mass index classified as overweight or obese. Since overweight status can worsen cancer outcomes and survival, a behavioral intervention of self-monitoring weight is commonly recommended in clinical practice. Purpose. However, given emerging evidence that self-weighing may have psychological consequences, the present pilot study aims to examine the effects of daily self-weighing on self-conscious emotions of guilt and shame. Methods. Women (n = 52) with a history of breast cancer who are seeking to manage their weight completed a weeklong daily diary study, where they self- weighed every morning and reported emotions associated with their weight both acutely (i.e., immediately after self-weighing) and distally (i.e., cumulative throughout day). Results. Women reported higher acute and distal shame and guilt during days in which their weight was higher than average. A history of weight cycling pre- and post-diagnosis did not moderate the daily relationship between weight and negative emotions. Conclusions. Drawing on these preliminary findings, we can conclude that recommended practices around frequent self-weighing may be psychologically detrimental among this vulnerable subset of women with obesity.