We evaluated the effect of the Ramadan fasting on plasma lipids and lipoproteins in normal individuals. Twenty-four healthy subjects were studied before the end of the Ramadan month (Ram) and for 1 mo thereafter. Plasma total cholesterol (TC), triglycerides, low-density-lipoprotein cholesterol (LDL-C), and very-low-density-lipoprotein cholesterol (VLDL-C) did not change. High-density-lipoprotein cholesterol (HDL-C) was 30% higher (P < 0.005) at the end of Ram; apolipoprotein A-I also increased (P < 0.0001). Both the ratios of TC to HDL-C and LDL-C to HDL-C (P < 0.001) decreased at Ram. There was a striking nonpharmacologic improvement in plasma HDL-C and ratios of TC to HDL-C and LDL-C to HDL-C, which were most probably induced by eating one large evening meal a day. Further studies to determine the mechanism of this observation are underway.