The types of potentially helpful dietary fat are mostly unsaturated: 1  Monounsaturated fatty acids. This is a type of fat found in a variety of foods and oils. 2  Polyunsaturated fatty acids. This is a type of fat found mostly in plant-based foods and oils. 3  Omega-3 fatty acids. One type of polyunsaturated fat is made up of mainly omega-3 fatty acids and may be especially beneficial to your heart. Omega-3, found in some types of fatty fish, appears to decrease the risk of coronary artery disease. There are plant sources of omega-3 fatty acids.