Egg whites, raw

Raw egg white (the clear part of an egg, separated from the yolk) is USDA FDC ID 172183 (SR Legacy, "Egg, white, raw, fresh"): 10.9 g protein and 52 kcal per 100 g, i.e. 20.96 g protein per 100 kcal — (10.9 / 52) x 100. One large egg white weighs about 33 g, providing roughly 3.6 g protein for 17.2 kcal; a common practical serving is 1 cup of liquid egg whites (about 243 g, roughly 7-8 egg whites' worth), which supplies about 26.5 g protein for 126 kcal. Per 100 g, egg white contains 0 mg cholesterol and only 0.17 g total fat — all of an egg's fat and cholesterol are concentrated in the yolk, which is why egg white is popular with people managing cholesterol or trying to cut calories while keeping protein high. FDC also lists 166 mg sodium per 100 g and small amounts of selenium (20 mcg) and riboflavin, but essentially no vitamin B12, vitamin A, or fat-soluble vitamins, again because those concentrate in the yolk — meaning an egg-white-only diet forgoes several nutrients whole eggs provide. The clearest caution is allergy: egg allergy is, per FARE, "among the most common food allergies in children," and the organization notes most of the allergenic proteins are concentrated in the white (though both white and yolk should be avoided by diagnosed individuals). The encouraging counterpoint is that most children who are allergic to egg eventually outgrow it. Separately, raw or undercooked egg white carries a small Salmonella risk like any raw egg product, which is why pasteurized liquid egg whites (sold in cartons in the refrigerated dairy case) are widely used for recipes or drinks that won't be cooked, and why the values here are for raw product intended to be cooked before eating. Egg whites — fresh-separated or pasteurized liquid-carton — are sold in virtually every US supermarket and are among the least expensive protein sources on this list per gram of protein.