Premenstrual variations of eating behavior are reported in several studies, but their relationship with mood is unclear. Eating behavior and physical and psychological complaints during the menstrual cycle were studied in 107 obese patients and 93 matched controls using retrospective (Weekly Bulimic Test Edinburgh, W-BITE and Premenstrual Assessment Form, PAF) and prospective (Daily Rating Form, DR) questionnaires. Eating disorder symptoms increased in the premenstrual phase, as shown by the W-BITE scores both in patients (6.2 +/- 5.3 premenstrual week vs 4.9 +/- 4.4 postmenstrual week, p < 0.05) and in control subjects (4.9 +/- 4.1 premenstrual week vs 4.2 +/- 3.0 postmenstrual week, p < 0.05) and were correlated to premenstrual complaints in control subjects (r = 0.5; p < 0.05) but not in obese women (r = 0.2; p = NS). A close relationship between physical and psychological premenstrual disturbances was observed in obese patients only. Premenstrual variation of eating behavior could be the target of specific treatment.