Last week, in discussing General Mills' new Cheerios Protein cereal, Mr. Tidbit ran out of the room before he could mention a peculiar contributor to the amount of protein in a serving of that cereal: serving size.
A serving of regular Cheerios (containing just 3 grams of protein) is 1 cup — 28 grams. The listed serving of Cheerios Protein (an amount of cereal containing 7 grams of protein) is 1 ¼ cups — weighing a whopping 55 grams — almost twice the weight of the serving of regular Cheerios! If you ate the same 55 grams of regular Cheerios (almost 2 cups), you'd get almost 6 grams of protein.
Why is a serving of Cheerios 1 cup (28 grams), while a serving of a light cereal such as Puffed Rice is 1 cup (14 grams), a serving of Cheerios Protein (pretty dense, because of the granola clusters) is 1 ¼ cup (55 grams), and a serving of Grape Nuts, a really dense cereal, is ½ cup (58 grams)? Why isn't the serving size 1 cup for all of them, or maybe 30 grams for all of them?
Here's the way the rules work, as explained to Mr. Tidbit long ago (things might well change as the FDA revises the nutrition label):
All serving sizes start with "the reference amount customarily consumed." There are three such amounts for cereal, based on density. (The idea is that the amount of cereal people serve themselves is based more on volume than on weight). For ordinary cereal (such as regular Cheerios), the reference amount is 30 grams (about an ounce). The manufacturer measures this amount of cereal and reports its volume to the nearest ¼ cup. Then they measure out that actual nearest-quarter-cup volume, and weigh it. That's the weight they report. For regular Cheerios, that's 1 cup, weighing 28 grams.
For very light cereals, such as Puffed Rice, the reference amount is 15 grams (about ½ ounce). For a dense cereal the reference amount is 55 grams (almost 2 ounces). Cheerios Protein is pretty dense, so they measure out 55 grams of it. Rounded to the nearest ¼ cup that's 1 ¼ cups, which happens to weigh 55 grams.
Clear? Or too dense?