TG/HDL cholesterol: is it a useful ratio?

The answer is yes because TG are high in postprandial and could be atherogenic through the chylomicrons remnants.
HDL cholesterol which is measured in the blood is the cholesterol content of HDL particles which clear lipids from tissues including arteries to the liver.
So a low TG and a high HDL cholesterol is a good marker of low carb and low calories diet combined to an transporter profile of lipid particles from the periphery to the liver.


http://circ.ahajournals.org/content/96/8/2520.full

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2664115/

http://www.ncbi.nlm.nih.gov/pubmed/16360350
It predicts LDL particle size:
http://www.ajconline.org/article/S0002-9149(04)00517-X/abstract and
http://www.sciencedirect.com/science/article/pii/S000291490400517X

The number of LDL particles is of paramount importance. Each LDL particles bear an Apo B100 protein. You can measure ApoB to have an idea of the number of LDL particles.
http://www.docsopinion.com/health-and-nutrition/lipids/apolipoprotein-b-apob/

What happens with TG?
http://www.jlr.org/content/42/6/891.full
http://www.jlr.org/content/25/13/1442.long
And the piece of Gary taubes:
http://www.sciencemag.org/content/291/5513/2536.full?ijkey=74d451fdc40527a727ca5651abee0b2e16377ed8&keytype2=tf_ipsecsha