Methods and compositions are provided for refining natural oils and for producing high-weight esters, high-weight acids, and/or high-weight derivatives thereof, wherein the compositions are made by cross-metathesizing low-weight unsaturated esters or low-weight unsaturated acids having hydrocarbon chain lengths less than or equal to C24 with an olefin feedstock, thereby forming a metathesized product composition including high-weight esters or high-weight acids having hydrocarbon chain lengths greater than C18, wherein at least a portion of the hydrocarbon chain lengths in the metathesized product are larger than the hydrocarbon chain lengths in the starting feedstock.