Almost everyone recommends eating more whole grains. The U.S. Dietary Guidelines, for instance, advise that at least half your daily grain intake be whole grains. That’s easier said than done, in part because it can be hard to identify truly “whole grain” foods. A recent Harvard study offers a simple way to increase the odds of choosing wisely: look for less than a 10-to-1 ratio of “total carbohydrates” to “fiber” on the nutrition label of whole-grain products. That’s the ratio found naturally in whole-wheat flour.
Whole grains retain the bran and germ and thus all (or nearly all) of the nutrients and fiber of the grain. But in many breads, cereals, granola bars, pastas and other products labeled “whole grain” or “multigrain,” the whole grain sits midway down the ingredients list, playing second fiddle to “wheat flour” (also called “white,” “refined” or “enriched” flour) and added sugars.
One sure way of finding whole grains is to look for a product labeled “100% whole wheat” or “100% whole grain.” If it doesn’t say that, you can look for a whole grain (such as whole wheat, barley or oats) listed as the first ingredient, though there still may be lots of refined wheat and/or sugar. Another option is to look for the voluntary “Whole Grain Stamp,” from the Whole Grains Council (supported by industry dues), which indicates there’s at least eight grams of whole grains in a serving.
The Harvard study, published in Public Health Nutrition, looked at 545 grain products and assessed the usefulness of the ratio, the Whole Grain Stamp and three general United States Department of Agriculture (USDA) guidelines for whole grains. It found that the ratio was the “best single metric” to “capture overall carbohydrate quality.”
What’s more, the ratio best identified whole-grain foods that are not only high in fiber but also lower in refined carbs and added sugars (both included in “total carbohydrates”), as well as lower in sodium and trans fat. Using the ratio means you don’t have to search through the ingredients list for the 29-plus different types of whole grains or the 21-plus types of added sugar.
Like all guidelines, this one is not perfect. A few whole grains, such as wild or brown rice or cornmeal, have slightly less fiber than whole wheat and thus don’t meet the 10-to-1 guideline, yet are still healthful. In addition, the ratio can’t distinguish between naturally occurring fiber and added “isolated” fiber, which may not have all the benefits of naturally occurring fiber. Many companies are now fortifying foods with isolated fiber such as inulin (chicory root) or pectin so they can make high-fiber claims.
Bottom line: The 10-to-1 ratio is a good tool to add to your healthy-food sleuthing resources. For instance, a cereal listing 36 grams of total carbs and 4 grams of fiber (a ratio of 9-to-1) would get a thumbs up, but one listing 42 grams of carbs and 3 of fiber (14-to-1) would not. If you aren’t nimble with numbers, here’s a shortcut: multiply the fiber grams by 10; the result should be more than the grams of total carbohydrates.