Hope this helps:
Dear Hungry Girl,
Why do you call for Egg Beaters or egg substitute in a lot of recipes and not egg whites? Can I use egg whites instead?
Dear Eggs-tremely Curious,
Thanks for the Q! I love fat-free liquid egg substitute. (And in case you're wondering, I like Egg Beaters Original and Better'n Eggs the most!) Truth is, egg sub is very similar to egg whites -- it's basically real egg whites with added nutrients -- and in most cases, they can be used interchangeably. A quarter-cup of egg substitute is equal to about two egg whites. (Liquid egg whites sold by the carton measure cup-for-cup like egg substitute.) You can easily make our egg-mug scrambles, omelettes, frittatas, and baked goods with egg whites. The only time egg whites DON'T work as well is when we faux-fry -- using egg substitute to help Fiber One "crumbs" adhere to different foods, like onions, jalapeno peppers, etc., before baking them. For some reason, the egg substitute just works better. BTW, hardboiled egg whites are an AMAZING snack. They only have about 15 calories each and they're ALL protein!