I was under the impression that egg yolks did more harm than good because of the cholesterol and fat they contain, and that the whites were an excellent source of protein. So I'm eating my salad with sliced hard boiled eggs one day, and I throw away all the yolks, eating only the whites. My coworker walks by, sees the yolks in the trash can, and turns to me in horror saying "What are you doing?! The yolk is the most nutritious part of the egg!" I was like, huh? And we argued back and forth to no avail... Anyone know anything about this? Yolk or no yolk?
Here's the scoop according to Dr. Andrew Weil (who I find to be the smartest and sanest voice in the current dietary battlefield): "Egg yolks contain a dazzling array of essential vitamins and minerals, particularly vitamins A, D, E and K and iron." In addition, the new "designer" eggs can provide omega-3 fatty acids which can help improve cardiovascular health. Basically, the whites are a source of protein and little else. And while the yolks do have saturated fat, they are also chock full of vitamins and minerals. So here's Weil's bottom line: "If you like eggs, I think it's fine to eat one or two a day, as long as you cook them without a lot of fat and use them in dishes that are consistent with the guidelines for healthy eating."
Dr. Barry Sears, author of The Zone, says that egg yolks are the worst kind of fat you can ingest. He strongly urges that you get your omega3 fatty acids from cold water fish (salmon is the best). Me, I love egg yolks, so I eat them anyway. In fact, add some bacon and heavily buttered sour dough toast (from Whole Foods, the best sour dough in town), and go run 3 miles. That is a good compromise plan, if you ask me.
If I am making them myself I usually screen about 1/2 or 2/3 of the yolks out--otherwise I more often asks for egg whites or egg beaters in a restaurant. If you are specifically concerned about avoiding foods that might not be good for your blood lipids/cholesterol profile (like me, who probably has to be extra stringent because of my genes) it is probably best to limit egg yolk consumption. If you have a high HDL (good cholesterol) and reasonable low "bad" cholesterol (LDL) and triglicerides (VLDL) I wouldn't worry about egg yolks because there is a lot of healthy aspects to them once you get beyond their saturated fat/cholesterol content.
