Although (fad) low carb, high protein and high fat diets appear to little change traditional risk factors ( cholesterol, LDL etc), mice studies appear to show that such diets can accelerate atherosclerosis through non-traditional risk factors viz. lowered levels of circulating endothelial progenitor cells and higher levels of non-esterified fatty acids.
Foo SY, Heller ER, Wykrzykowska J, et al. Vascular effects of
a low-carbohydrate high-protein diet. Proc Natl Acad Sci U S A
2009 August 24 http://www.pnas.org/content/106/36/15418.long