By Dr. Jean Harvey-Berino, Ph.D., R.D., The EatingWell Diet (2007)
Note that a “serving” and a “portion” are often used interchangeably, but they’re not the same thing. A serving is a standard unit of measure, for example, one egg or half a hamburger bun—as established by nutritionists and published in government documents. But a portion refers to how much food we actually eat—two eggs scrambled, perhaps, or the whole burger bun. So, while technically 1⁄2 cup of spaghetti is “one serving,” few of us would actually consider that a “portion.” (Some might consider it the first forkful.) A spaghetti portion of 1 cup, or even 11⁄2 cups, is more realistic. But if that’s what you’re eating, know that you’ve eaten two or three servings of grain-based foods when you dig into that bowl of pasta.