All saturated fatty acids, with the notable exception of stearic acid (C18:0), raise low-density lipoprotein (LDL) cholesterol levels. A few less ubiquitous fatty acids also have LDL cholesterol effects. Trans-monounsaturated fatty acids, at equivalent doses of saturated fatty acids, raise LDL cholesterol. Polyunsaturated fatty acids, at three times the dose of saturated fatty acids, lower LDL cholesterol. Higher intakes of most fatty acids raise high-density lipoprotein (HDL) cholesterol, with the notable exception of trans-monounsaturated fatty acids, which lower HDL cholesterol to the same extent as carbohydrate when either is substituted for other dietary fatty acids. Conjugated linoleic acids containing both cis and trans bonds and cis-monounsaturated fatty acids neither raise nor lower cholesterol concentrations of lipoproteins. The omega-3 fatty acids from fish lower triglyceride levels. Although dietary composition remains an important, modifiable predictor of dyslipidemia, overconsumption of any form of dietary energy may replace overconsumption of saturated fat as the primary factor that increases lipid and lipoprotein levels.