Can be produced directly 1
Small VLDL2 / large IDL1 lead to mid sized LDL2, while small IDL2which is similar in size and density to large LDL1, is the metabolic precursor to these particles. IDL1 is part of a delipidation cascade, thus we go VLDL->IDL -> LDL, but IDL2 is directly secreted (possibly in the liver), and thus the arising LDL remains in the same size and density region.
1Gaw, A., C. J. Packard, G. M. Lindsay, B. A. Griffin, M. J. Caslake, A. R. Lorimer, and J. Shepherd. 1995. Overproduction of small very low density lipoproteins (Sf 20–60) in moderate hypercholesterolemia: relationships between apolipoprotein B kinetics and plasma lipoproteins. J. Lipid Res. 36: 158–171.