Whole Egg
Whole Egg: Nutrition, History and Complete Cooking Guide
The egg — produced by the domestic hen (Gallus gallus domesticus) — is one of the most nutritionally complete single foods available and has been central to human diets for thousands of years. Archaeological evidence suggests that jungle fowl were domesticated in Asia at least five thousand years ago, and domestic chickens had spread from South and Southeast Asia through China and the Indian subcontinent, into the Middle East, Africa, and eventually Europe by the classical period. In ancient Rome, eggs were eaten at nearly every meal and featured in the first course of formal banquets — giving rise to the Latin expression "ab ovo usque ad mala" ("from the egg to the apples," meaning from beginning to end, equivalent to the modern English "from soup to nuts"). In mediaeval Britain, eggs were a dietary staple for all social classes — peasant households kept laying hens, monasteries maintained substantial flocks, and eggs appeared in countless recipes in the earliest surviving English cookbooks. The egg's remarkable nutritional completeness — it contains all the nutrients required to grow a living organism — makes it an extraordinary food by any measure. It provides complete protein with an excellent amino acid profile, fat including essential fatty acids, vitamins, and minerals in a single, affordable, versatile package.
Nutritional Value of Whole Eggs
A whole egg provides 143 kcal and 12.6 g of protein per 100 g, with 9.5 g of fat (including 3.1 g saturated fat). A single large egg weighs approximately 50–60 g, providing around 70–85 kcal, 6–7 g of protein, and 5 g of fat. Eggs are an outstanding source of vitamin B12, riboflavin (B2), folate, vitamin D, vitamin A, vitamin E, and choline — a nutrient critical for brain development and liver function that is deficient in many modern diets, and for which eggs are the single best common dietary source (approximately 125 mg per egg). They provide selenium, iodine, phosphorus, and zinc in meaningful quantities. The yolk contains all the fat, all the fat-soluble vitamins (A, D, E, K), and most of the choline, iron, and zinc; the white provides most of the protein and B vitamins. Eggs from hens raised outdoors on pasture — particularly those with access to insects, grass, and natural light — typically have higher levels of vitamin D, omega-3 fatty acids, and vitamin E than eggs from caged hens.
Health Benefits and the Cholesterol Question
Eggs were subject to decades of nutritional controversy centred on their cholesterol content — a single egg contains approximately 185–200 mg of dietary cholesterol, concentrated in the yolk. For much of the late twentieth century, dietary guidance in many countries recommended limiting egg consumption due to concern that dietary cholesterol would raise blood cholesterol and increase cardiovascular risk. The current scientific consensus has largely overturned this concern for most healthy people: dietary cholesterol has relatively little effect on blood cholesterol levels in most individuals, because the liver adjusts its own cholesterol synthesis in response to dietary intake. Large prospective studies have generally found no significant association between moderate egg consumption (up to one egg per day) and cardiovascular disease in healthy adults. Eggs provide choline, which supports brain health, liver function, and fetal neural development — pregnant women benefit particularly from adequate choline intake. The protein quality of eggs is exceptional — the egg is used as the reference standard against which all other dietary proteins are measured (the protein digestibility-corrected amino acid score). Eggs promote satiety: studies consistently find that an egg-based breakfast produces greater fullness and reduced caloric intake at subsequent meals compared to cereal or toast-based breakfasts of equivalent calories.
How to Select and Store Eggs
In Britain, eggs are sold by the Lion Code quality mark scheme — the British Lion mark on an egg indicates it was produced under a code of practice that includes vaccination of hens against Salmonella, which means Lion-marked eggs are considered safe to eat lightly cooked or raw in the UK. Eggs are graded by weight: small (under 53 g), medium (53–63 g), large (63–73 g), and very large (over 73 g). Free-range and organic eggs come from hens with outdoor access and are considered both more ethically produced and nutritionally superior, particularly for vitamin D. Store eggs in the refrigerator — eggs stored at room temperature deteriorate faster, and refrigerated eggs can be kept safely for three to four weeks. In Britain, unwashed eggs retain their protective cuticle and can be stored at room temperature for a shorter period — washed eggs (common in the US) must be refrigerated.
How to Cook Eggs
Eggs are among the most versatile ingredients in any kitchen. For scrambled eggs: beat with a splash of milk or water, cook over medium-low heat with butter, stirring gently and removing from heat slightly before they look fully set. For fried eggs: cook in butter or oil in a non-stick pan over medium heat until the white is set and the yolk is at your preferred doneness. For poached eggs: bring water to a gentle simmer with a splash of vinegar, swirl to create a vortex, crack the egg in and simmer for three to four minutes. For boiled eggs: soft-boiled (six minutes from boiling); hard-boiled (ten minutes). For omelettes: beat eggs with salt, pour into a hot buttered pan, draw the sides in as they set, then fold. The most important rule across all egg cookery: do not rush with high heat — eggs seize and become rubbery if overcooked. Patience and moderate heat produce the finest results.
The egg is the most rehabilitated food in modern nutrition advice. For roughly thirty years, UK and US guidance capped egg consumption on the basis of their cholesterol content. That cap has gone: the British Heart Foundation and NHS advice now place no limit on the number of eggs a healthy adult eats, because dietary cholesterol turned out to have far less effect on blood cholesterol than saturated fat does. The practical corollary is that what you cook the egg in matters more than the egg. A poached or boiled egg is a 143 kcal-per-100 g food; the same egg fried in butter is a different proposition, and the butter is where the saturated fat comes from. On safety, the UK position changed too. Since 2017 the FSA has advised that eggs produced under the British Lion scheme — vaccinated flocks, traceable, stamped with the lion mark — are safe to eat raw or lightly cooked, including by vulnerable groups: pregnant women, infants and older people. That reversed decades of advice dating from the salmonella crisis of the late 1980s. Non-Lion and imported eggs are not covered. Two kitchen facts that follow from the chemistry. Older eggs peel more easily after boiling, because the white becomes less acidic and adheres less to the membrane — so buy eggs a week ahead if you want peelable boiled eggs. And the greenish ring around an overcooked yolk is iron sulphide, formed from sulphur in the white and iron in the yolk; it is harmless and entirely a signal that the egg cooked too long or too hot. Per 100 g of whole raw egg, this page's panel shows Vitamin B12 (Cobalamin) at 2.7 µg (about 180% of the adult reference intake), Vitamin B2 (Riboflavin) at 0.5 mg (38%), Iodine at 50 µg (36%), Phosphorus at 179 mg (33%), Vitamin D at 3.2 µg (32%), Vitamin E at 1.29 mg (32%), Selenium at 23 µg (31%), Vitamin B9 (Folate / Folic acid) at 47 µg (24%), Vitamin B3 (Niacin) at 3.5 mg (21%) and Vitamin A at 126 µg (18%). Eggs are one of the very few foods that contain every nutrient a body needs except vitamin C and fibre, and one of the few natural sources of vitamin D outside oily fish. They are also among the richest ordinary sources of Choline, which matters particularly in pregnancy. Almost all of the micronutrient content and all of the fat sit in the yolk; the white is essentially protein and water. Discarding yolks removes most of what makes an egg nutritionally interesting. Source: CoFID 2021 (McCance and Widdowson, UK), code 12-937 (matched record: "Eggs, chicken, whole, raw"). N = present but not quantified; Tr = trace; not measured = no value in the source. High in by content (per 100g): Vitamin B12 (180%), Vitamin B2 (riboflavin) (38%), Iodine (36%), Phosphorus (33%), Vitamin E (32%), Vitamin D (32%), Selenium (31%). A source of by content (per 100g): Vitamin B9 (folate) (24%), Vitamin B3 (niacin) (21%), Vitamin B5 (pantothenic acid) (19%), Vitamin A (18%). These figures are the amount in the food. How much the body absorbs can vary, see each nutrient's entry for detail.Whole Egg in more detail
Nutrients worth knowing about
Other eggs
Micronutrients (per 100g, raw)
Nutrient Amount % adult reference intake Minerals Iron 1.72 mg 12% Calcium 46 mg 7% Magnesium 13 mg 4% Potassium 145 mg 4% Sodium 154 mg 10% Chloride 180 mg 7% Phosphorus 179 mg 33% Zinc 1.1 mg 12% Copper 0.05 mg 4% Manganese 0.03 mg 2% Iodine 50 ug 36% Selenium 23 ug 31% Vitamins Vitamin A 126 ug 18% Vitamin C 0 mg 0% Vitamin D 3.2 ug 32% Vitamin E 1.29 mg 32% Vitamin K Tr (trace) . Vitamin B1 (thiamin) 0.08 mg 8% Vitamin B2 (riboflavin) 0.5 mg 38% Vitamin B3 (niacin) 3.5 mg 21% Vitamin B5 (pantothenic acid) 1.35 mg 19% Vitamin B6 0.13 mg 9% Vitamin B7 (biotin) 19.5 ug 10% Vitamin B9 (folate) 47 ug 24% Vitamin B12 2.7 ug 180% What this food is a source of