To answer that question, let's first start with some background information on eggs.
Eggs have three sections: the eggshell, egg yolk (vitellus) and egg white (albumen). In totality, they contain retinol (vitamin A), riboflavin (vitamin B2), folic acid (vitamin B9), vitamins B6, Vitamin B12, Vitamin D, choline, iron, lutein (pigment in egg yolk), calcium, phosphorus, and potassium. All of the egg's vitamin A, D, and E are in the egg yolk.The egg white supplies all of our essential amino acids and you can get all the protein you need from them.
The average sized egg also contains 200 milligrams of cholesterol, about two-thirds of the recommended daily intake. For most people, it is generally believed that cholesterol in food has no effect on blood levels of cholesterol as most of the body's cholesterol originates in the liver.
Here's where it gets tricky. The largest study that analyzed the relationship between egg consumption and heart disease showed no link between consuming one egg a day and the development of heart disease or having a stroke. However, this was not true for diabetics. There was an increased risk of heart disease in diabetics.
So as with with the two sided story with wine, here's my take. More than half of the egg's protein comes from the egg white and there are no valid reasons to restrict consumption of a healthy egg white. As to the egg yolk, everything good in it can be obtained from other natural food sources. Spinach, for example, supplies both the choline and lutein we need for eye health.
An egg yolk every once in a while will probably do you no harm (except perhaps if you are diabetic and there seems to be a growing epidemic of pre-diabetes in our society). Nevertheless, I recommend limiting consumption of egg yolks to no more often than 1-2 yolks maximally a week. Personally, I no longer consume egg yolks except in certain baked products. I do, however, eat a lot of green vegetables, particularly spinach.
So the next time someone asks you how you want your eggs, perhaps your best answer is "egg white only, with spinach, onions, and mushrooms, with no added oil." Sounds yummy, right?