Systems and methods are disclosed for refining natural oil feedstocks. In some embodiments, the methods comprise transesterifying glycerides in a natural oil feedstock to provide a transesterified product comprising monounsaturated fatty acid esters and polyunsaturated fatty acid esters. In some embodiments, the methods comprise separating the polyunsaturated fatty acid esters from the monounsaturated fatty acid esters (or vice versa), to provide a separated monounsaturated fatty acid ester composition having a ratio of at least 10 parts by weight of monounsaturated fatty acid esters for every 1 part by weight of polyunsaturated fatty acid esters.