There is no shortage of advice for women on what to eat, how to train, or what supplements to take during their menstrual cycles, but a new review by an international team of scientists has found little evidence to support such recommendations. In fact, they found sparse research on women and exercise at all, and even less on the effect of their periods on sports performance, physiology, or physical fitness. The authors of the paper, from McMaster University, Manchester Metropolitan University and the Australian Catholic University in Melbourne, are calling for much more high quality, standardized research on women. They found few or no differences when they looked at exercise results across the cycle phases and examined women’s use of fat versus carbohydrates, the potential for muscle growth, or blood-vessel function. “Many women are following advice and planning exercises and practices based on some ostensible benefit of menstrual cycle phase-based exercise. We saw no evidence that such practice is science-based,” said Stuart Phillips, a professor in the Department of Kinesiology at McMaster and senior author of the review.