have been attempting pregnancy for at least 6 months is not currently pregnant has a clinical diagnosis of PCOS is not on oral medications for insulin resistance (such as metformin) or, if currently on such a medication, has been on the medication at a stable dose for at least 3 months willing not use fertility-enhancing medications over the 6-month study (with the exception of oral medications, such as clomiphene citrate, as directed by their physician) willing to be randomized to either dietary condition and able to make weekly meetings.