Egg whites or whole eggs: is the yolk the problem?

An egg is two different foods sharing a shell. The white of a large egg is about 17 calories and close to pure protein: three whites give you around eleven grams for roughly fifty calories, with essentially no fat and no cholesterol. The yolk is where everything else lives, including about 4.5 grams of fat, a third of it saturated, and most of an egg's 185 milligrams of cholesterol. Splitting them lets you keep everything the egg is good for and leave behind the part a heart diet is trying to reduce.

That split is not something I invented. When Dean Ornish designed the Lifestyle Heart Trial, the diet permitted no animal products at all with two exceptions, and egg white was one of them. It is the same call, made for the same reason, by a physician running a trial that measured arteries.

Now the evidence on whole eggs, which is genuinely split, and I would rather show you the split than pick the half that suits me. On one side, an analysis of three large American cohorts with an updated meta-analysis found that moderate intake, up to about one egg a day, was not associated with cardiovascular disease overall. Dietary cholesterol turned out not to be the villain it was treated as for forty years, and in 2015 the American guidelines dropped the daily limit on it. If you eat an egg a day, nothing dramatic is happening to you.

On the other side sits the largest cohort to look at this directly: 521,120 adults followed for a median of sixteen years. Each additional half a whole egg a day was associated with about seven percent higher mortality from all causes, and the analysis attributed roughly sixty percent of that to the cholesterol. In the same cohort, people who ate egg whites or egg substitutes had lower mortality than people who ate none, and swapping half a whole egg for the same amount of egg white was associated with lower cardiovascular and cancer mortality.

Notice what that last finding is. It is not a study saying eggs are poison. It is a study of the exact swap I am asking you to make, and the swap came out ahead. Both sides are observational, built on food questionnaires, and neither can prove cause, which is worth holding in mind about almost everything in nutrition. The honest summary is that the evidence for separating the yolk from the white is better than the evidence for any other position on eggs.

The other reason is simpler than any cohort. My rule is not about eggs. It is about saturated fat, and the yolk is where an egg keeps it. Fish fat is animal fat and stays on the LP3 plate because it is largely unsaturated. Coconut oil is a plant fat and does not, because it is more saturated than lard. Whole eggs sit on the wrong side of that line and whites sit on the right side, and once you see it that way the rule stops looking arbitrary.

In practice, whites are the easiest protein in the kitchen. A carton of them keeps for weeks, cooks in three minutes, and puts real protein into breakfast, which is the meal that breaks most people. Chapter three of The LP3 Diet has the three lines the plate draws, on red meat, eggs and dairy, and the reasoning behind each.