I try to avoid eating vegetable oil. I understand that the polyunsaturated oils are preferentially stored to protect the body from these unstable oils. The Center for Science in the Public Interest needs to eat some crow.
The entire nutrition science industry needs to start reporting confidence levels associated with studies. Almost all nutritional advice is based on small studies. That's why you see them contradict each other on a frequent basis. You need a 5 sigma result to discover a new particle. Discovering new particles doesn't kill people.
I doubt they'll ever really expand beyond small studies in that field. There's certain groups that routinely do meta-analyses of nutritional (and other) studies, like the Cochrane Collaboration. E.g., Effect of cocoa on blood pressure: http://www.cochrane.org/CD008893/HTN_effect-of-cocoa-on-bloo...
That's really the only way to be confident, short of setting up a massive (expensive) randomized controlled trial.