The dietary intakes of eight human females were obtained by interview each day for 60 days to determine whether the menstrual cycle affected patterns of food intake. The study was double blind in the sense that the subjects did not know its purpose, while the interviewer did not know the timing of their cycles. Mean differences in calorie intake between 10 preovulation and 10 postovulation days were calculated. For cycle one the difference was 504 (SD = 219) and for cycle two, 496 (SD = 378) cal/day, with the postovulation food intakes being higher in calories. A dependent t test was performed and these differences were found to be significant at p less than 0.0004 for cycle one and p less than 0.008 for cycle two. The evidence indicates that women eat more food per day during the 10 days after they ovulate than during the 10 days before.