The objective of this pilot study was to evaluate possible differences in insulin sensitivity, food intake, and cravings between the follicular and luteal phases of the menstrual cycle in women with premenstrual syndrome (PMS). Subjects were screened for PMS using the Penn Daily Symptom Rating (DSR) scale. Each subject had two overnight admissions (once in each cycle phase) to the Hospital of the University of Pennsylvania. They performed 3-day diet histories prior to each hospitalization. After admission, subjects received dinner and a snack, then were fasted until morning, when they underwent a frequently sampled intravenous glucose tolerance test (FSIGT). Insulin sensitivity was determined by Minimal Model analysis. Blinded analysis of diet histories and inpatient food intake was performed by a registered dietitian. There was no difference found in insulin sensitivity between cycle phases (n = 7). There were also no differences in proportions of macronutrients or total kilocalories by cycle phase, despite a marked difference in food cravings between cycle phase, with increased food cravings noted in the luteal phase (p = 0.002). Total DSR symptom scores decreased from a mean of 186 (+/-29.0) in the luteal phase to 16.6 (+/-14.2) in the follicular phase. Women in this study consumed relatively high proportions of carbohydrates (55%-64%) in both cycle phases measured. These findings reinforce the suggestion that although the symptom complaints of PMS are primarily confined to the luteal phase, the neuroendocrine background for this disorder may be consistent across menstrual cycle phases.