They get oxidized more easily. Arterial plaque is oxidized fatty acids. Fatty acids are essential to cell wall formation. Deductively, fatty acids which are more susceptible to reactive oxidation species (aka free radicals) will lead to more cell damage. It's an interesting topic and the nutritional science (PUBMED) is very far away from the popular perception (ex Time magazine).

- http://www.ncbi.nlm.nih.gov/pubmed/16757819 - https://www.youtube.com/watch?v=T78cJv6gi88 - http://oregonstate.edu/dept/biochem/hhmi/hhmiclasses/biochem...