Suggest Diet To Lower Cholesterol Level

My doctor told me today that my LDL is 155 and my HDL is 83. Because I have low blood pressure, 120/70, and have no other health problems he doesn't feel I'm at serious risk. He suggested doing a carotid artery Dobler study before he decides weather to put me on medication. Would you recommend a diet to lower my cholesterol so that I don't have to go on medication?