http://circ.ahajournals.org/cgi/content/full/4304635102

b) Trans-Fatty Acids
It has been established that dietary trans-unsaturated fatty acids can
increase LDL cholesterol and reduce HDL cholesterol.54 55 Such fatty acids
are found in prepared foods containing partially hydrogenated vegetable oils
(eg, cookies, crackers, and other baked goods, commercially prepared fried
foods, and some margarines). In addition, there may be a high content of
trans-fatty acids in oils used to prepare fried foods in most restaurants
and fast-food chains. The AHA recommends limiting the intake of trans-fatty
acids, the major contributor of which is hydrogenated fat. Future inclusion
of trans-fatty acid content on food labels, as well as the increasing
availability of trans-fatty acid-free products, will aid consumers in
reducing current intake (average 2% to 3% of total energy) to achieve a
total intake of cholesterol-raising fatty acids that does not exceed 10% of
energy.