OBJECTIVE: To determine parameters of weight history useful for the assessment of weight cycling and their association with psychological distress and binge eating. DESIGN: Cross-sectional. SUBJECTS: A total of 1889 treatment-seeking obese subjects, enrolled by 25 Italian centers (78% female subject), aged 20-65 y (median 45); 1691 reported previous efforts to lose weight (median age of first dieting, 30 y). MEASUREMENTS: The number of yearly attempts to lose weight, weight gain since age 20 y, cumulative weight loss and gain were checked by a predefined structured interview. Psychological distress was tested by means of Symptom Check-List 90 (SCL-90), Binge Eating Scale (BES) and Three Factor Eating Questionnaire (TFEQ). RESULTS: Differences in anthropometric, clinical and psychological parameters were observed in relation to previous attempts to lose weight. Patients in the upper quartile of parameters of weight history were considered weight cyclers. In multivariate logistic regression analysis, after correction for age, sex and BMI, a high BES score was the only factor systematically associated with a high frequency of dieting (OR, 1.70; 95% confidence interval, 1.22-2.36; P=0.022), with higher cumulative weight loss (1.42; 1.12-1.80; P=0.003) and cumulative weight gain (1.38; 1.06-1.79; P=0.017). However, the sensitivity, specificity and positive predictive value of a high BES score were very low to detect cyclers. Weight cycling did not carry a higher risk of complicating diseases. CONCLUSIONS: Weight cycling is associated with psychological distress, and binge eating independently increases the risk, but cannot be used to predict cycling. Also, obese patients who do not experience overeating as a loss of control discontinue treatment or regain weight following therapy.