

With the change in her diet her cycle “immediately became predictable and mild,” she says. The reason Kastor switched to a mostly plant-based diet (occasionally eating fish or eggs) was due to age-related hormone changes and debilitating, unpredictable menstrual cycles. “My entire adult life I’ve been cautious about eating animal proteins from quality sources, and almost never eat animal protein while at a restaurant unless it specifically says that it’s sustainably sourced, grass-fed, free range, local, and organic.” If she were to take a guess at how much animal protein is in her diet, Deena Kastor, American women’s record holder in the marathon, would say it’s down to about 10 percent. Heading out the door? Read this article on the new Outside+ app available now on iOS devices for members!
