Polyunsaturated fats are
lipids in which the constituent
hydrocarbon chain possesses two or more carbon–carbon
double bonds. Polyunsaturated fat can be found mostly in nuts, seeds, fish, algae, leafy greens, and krill. "Unsaturated" refers to the fact that the molecules contain less than the maximum amount of hydrogen. These materials exist as
cis or
trans isomers depending on the geometry of the double bond.