When eaten in moderation, eggs are not a fattening food. Especially when eaten on their own, eggs do not cause a buildup of fat in healthy humans. Eggs are a very healthy food to include in a diet.
The history behind eggs as an unhealthy or fattening food stems from the belief that cholesterol in egg yolks contributes to cholesterol in the cardiovascular system. This belief has been proven wrong, and the cholesterol in eggs has little to no effect on blood cholesterol in healthy individuals. Eggs do not contain unhealthy fats in any significant amount, and are instead great sources of both protein and healthy omega-3 fatty acids that improve the health of the consumer.
Whole eggs are filled with valuable minerals and vitamins that are essential to a healthy diet and are healthy on their own. Eggs become fattening when cooked with a lot of added oil, butter and fat. When these additional ingredients are not added or are kept to a minimum, eggs remain a food that is low in calories and high in nutrients and protein. Egg whites are a common alternative to whole eggs, and are often used to bulk up an egg dish without the added calories of the yolk, but separating the two is not necessary to avoid fattening results.