We've explained the science behind the food pyramid and how to use it effectively, but the oft-used term "serving" is rather vague and subjective. Here's one way to measure servings without pouring everything into a measuring cup.
Since the creation of the food pyramid in the 1970s, serving sizes have steadily increased to the point where the average American is taking in about 20% more calories than they used to. Furthermore, even those that don't eat "too much" have trouble deciding what "2-3 servings" of a specific food group is. While it's always good to measure out your food once in a while, and to learn how to eyeball what a good serving size is, food blog Cheap Healthy Good shows us how to use other objects to "measure" a serving size:
If you don't have measuring cups handy, there are other ways of estimating portions. For example, this guide from Prevention Magazine shows you how to use your hands when calculating amounts. Diabetic Living has a slideshow comparing serving sizes to everyday objects, like CDs, computer mice (mouses?), and shotglasses.
It's not an exact science, of course, but it does provide a nice guideline to nailing down what "2-3 'servings'" of something really is, and how much of each food group you actually need to eat a day (whether that be less than you originally thought or more). Hit the link for more tips on serving sizes and portion control.
Serving Sizes and Portion Control: A Primer [Cheap Healthy Good]