April 1, 2026, 2:03 am | Read time: 7 minutes
Eggs are primarily composed of proteins–the yolk contains slightly more than the white, so it’s sensible to eat the whole egg. But what next? After all, eggs can be prepared in very different ways. Depending on the method, eggs not only taste different but also vary in texture. Their effect on the body also changes. Boiling, frying, scrambling–what is the healthiest way to prepare eggs? And can you actually eat them raw, given how healthy they are?
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Why Choose Eggs at All?
Few foods are as controversially discussed as the chicken egg. Once demonized as a cholesterol bomb–a 60-gram egg contains 240 milligrams of cholesterol–it is now praised as the best protein source and consumed in fitness circles for muscle building. What is certain: Eggs are rich in high-quality protein and other essential nutrients like fat-soluble vitamins (A, B, D) and minerals such as phosphorus and iron. What many don’t know: The nutrient density of an egg is influenced by its preparation method. The calorie content is also not set in stone. What is the healthiest way to prepare eggs?
Common Egg Preparation Methods
Boiled Egg: Eggs are placed in boiling water with the shell for about five to ten minutes. The longer the cooking time, the harder the egg becomes. The texture ranges from soft to hard.
Fried Egg: For the perfect fried egg, oil or fat is first heated in a pan. Then the egg is carefully slid into the pan whole. If it’s fried on one side only, it’s called “sunny side up” or a set egg. The “over easy” version is fried on both sides.
Scrambled Egg: To prepare scrambled eggs, the eggs are first cracked into a bowl and whisked. Sometimes a little water or milk is added to the liquid eggs. The whisked eggs are then poured into a pan with hot fat. Once they set, they are moved around with a spatula to form small pieces.
Poached Egg: Poached eggs, also called “lost eggs,” are placed without the shell in simmering water (about 70 to 80 degrees Celsius) and cooked for two and a half to five minutes. They are then scooped out of the water. A popular form of poached eggs is “Eggs Benedict.” In this American breakfast classic, the poached egg is served on a slice of toast with fried bacon and hollandaise sauce.
Omelet: The omelet is prepared similarly to scrambled eggs. The only difference: While scrambled eggs are broken into pieces, the omelet remains whole. Often, chopped vegetables, fresh herbs, ham cubes, or cheese are added.
What Happens When an Egg is Boiled–Biochemical Explanation
Eggs are mainly composed of proteins. This protein content consists of various types of proteins, including ovotransferrin and ovalbumin. These proteins are made up of long chains of amino acids, arranged like a loose, three-dimensional tangle. When boiled, this tangle changes. On one hand, the proteins lose their original spatial structure. On the other hand, different proteins clump together during cooking. It’s as if the tangle unravels a bit and then is tightly re-knotted. This makes the protein structure denser.
This also explains why eggs become hard when boiled. The yolk, by the way, stays soft longer than the white because it is isolated inside and reached by heat later.
Heating Egg Protein Improves Absorption in the Body
Heating breaks down the protein molecules, making them easier to digest. Researchers at the University of Leuven in Belgium have shown that the absorption rate of cooked egg protein is 90.9 percent. In contrast, the “digestibility” of raw egg protein is only 51.3 percent.1 This shows that the digestibility of egg protein is significantly improved by heat.
Vitamin A and D Content Decreases with Heating
The situation is different with the other nutrients in the egg. A 2006 study showed that the vitamin A content decreases by up to 20 percent when heated.2 The vitamin D content also decreases when eggs are heated. A 2016 study showed that eggs baked for over 40 minutes lost 61 percent of their vitamin D content. However, when they were only briefly boiled, the loss was significantly lower at just 18 percent.3 It’s also important to know: To minimize nutrient loss, eggs should be heated as gently as possible.
Also interesting: Eating eggshells–healthy or dangerous?
What a Green Ring on Hard-Boiled Eggs Means
An egg should not be boiled for more than ten minutes. Otherwise, a bluish-black ring forms on the yolk. This indicates that the iron in the yolk has reacted with the sulfur in the white to form iron sulfide. It’s not pretty, but it’s not harmful to health. Such eggs can be eaten–unlike raw eggs.
Why Raw Eggs Aren’t Healthy
The idea that raw eggs are particularly good for muscle building is a myth. As mentioned earlier, protein is better absorbed by the body when heated.
Raw eggs pose the risk of salmonella and other bacteria. In the worst case, consuming raw eggs can lead to food poisoning. If you still insist: Washing the shell with hot water can at least partially reduce the risk of salmonella.
Raw eggs also contain the glycoprotein avidin. Excessive consumption of raw egg whites can hinder biotin absorption in the intestine.
Calorie Content of a Chicken Egg by Different Preparation Methods
Here are the approximate calorie counts for a 60-gram egg based on different preparation methods. Naturally, the calorie content changes with the addition of other ingredients. For example, “Eggs Benedict” can quickly become a high-calorie dish due to the sauce, as can a filled omelet.
- boiled egg: 155 calories per 100 grams
- poached egg: 155 calories per 100 grams
- scrambled egg (from one egg): 173 calories per 100 grams
- fried egg (fried with fat): 220 calories per 100 grams
What Else Affects the Nutrient and Calorie Content of a Chicken Egg
The nutrient and calorie content of an egg also strongly depends on the chickens’ husbandry and feeding.
This is the Healthiest Way to Prepare Eggs–Conclusion
To minimize nutrient loss, eggs should be heated as gently as possible. Gentle cooking, such as poaching, is a suitable method. But moderate, short boiling also only slightly reduces the nutrient content. Poached and boiled eggs are the lowest-calorie options.
Egg Consumption–How Much is Okay?
It’s true that eggs contain a lot of cholesterol. An egg of class M has a cholesterol content of 200 to 230 milligrams. The German Nutrition Society (DGE) recommends consuming no more than about 300 milligrams of cholesterol per day. Since cholesterol is also found in other animal products such as dairy, meat, and sausages, the daily requirement is quickly met–and you could easily exceed it with just one egg a day. The DGE therefore recommends consuming no more than two to three eggs per week to prevent high blood lipid levels and resulting heart diseases.
Nutritional physician Dr. Matthias Riedl is relaxed about cholesterol intake from eggs. “Egg consumption is not relevant to cholesterol levels,” he told FITBOOK. For some people, it even lowers cholesterol, for others it remains the same or slightly increases. But all of this is “not relevant.” People with chronically high cholesterol levels and those with rheumatic diseases should be cautious. According to Riedl, they should especially avoid egg yolks and animal fats, “because they promote inflammation,” Riedl told FITBOOK.