The participants with severe obesity had reduced HDL particle size, apolipoprotein A1, total cholesterol and HDL, HDL2, and HDL3 cholesterol, and degree of fatty acid unsaturation and increased LDL/IDL triglycerides and LDL diameter (odds ratios shown in Figure 1). This evidence concerns the gene APOA1 and obesity due to melanocortin 4 receptor deficiency.