Egg yolk

The egg yolk is the yellow inside an egg. Its primary purpose is to serve as a food reserve for the developing embryo.

The egg yolk contains a small amount of fat and cholesterol, and people on a low-cholesterol diet may feel the need to cut down on egg consumption, although most of the fat in egg is unsaturated fat and may not be harmful. The egg white consists primarily of water (seven eighths) and protein (one eighth) and contains no cholesterol and little if any fat.