the problem is you can't tell in many cases, so we might as well eat healthy. In my case, I didn't know and couldn't know until I got to the age where the coronary artery disease genetically kicks in. I am LUCKY I maintained excellent habits and missed massive plaque buildup in my arteries. Some of my cousins weren't so lucky and died in their 60s. Dad had a massive heart attack at 58 and he swam 3 times a week. Now they have a test "LPa" - so I got the test - found out I inherited CAD. Lucky, lucky, lucky - I incorporated a low-fat diet my whole adult life!