The trick to recognizing a good whole grain: Use carb-to-fiber ratio of 10-to-1

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“Whole grain” has become a healthy eating buzzphrase, and food companies aren’t shy about using it to entice us to buy products. Browse the bread, cereal, or chip aisle of your favorite grocery store and you’ll see what I mean. Last year, nearly 3,400 new whole-grain products were launched, compared with just 264 in 2001. And a poll by the International Food Information Council showed that 75% of those surveyed said they were trying to eat more whole grains, while 67% said the presence of whole grains was important when buying packaged foods.

But some of the products we buy may not deliver all the healthful whole-grain goodness we’re expecting. If sugary Froot Loops can tout itself as a whole-grain food, there’s something amiss.

What’s the best way to identify a healthful whole-grain food? I struggle with this question often while shopping. There several competing recommendations. The current Dietary Guidelines for Americans says to choose grain products that have the word “whole” before any grain in the ingredient list. The USDA’s MyPlate recommends choosing grain products with a whole grain as the first item in the ingredient list or listing whole grain as the first item and containing no added sugars. The nonprofit Whole Grains Council promotes the Whole Grain Stamp, which a company can place on its packaging if the product contains at least eight grams of whole grains per serving.

There’s a better way. Use this rule when choosing whole-grain foods: for every 10 grams of carbohydrate there should be at least one gram of fiber. Why 10:1? That’s about the ratio of fiber to carbohydrate in a genuine whole grain—unprocessed wheat. This recommendation comes from a new report from the Harvard School of Public Health published online in the journal Public Health Nutrition.

The Harvard researchers evaluated 545 grain products from two major grocery store chains, Stop & Shop and Walmart. They tallied up grams of whole grains in each product, along with the amounts of carbohydrates, fiber, added sugar, trans fat, and sodium, plus the number of calories. Foods that met the 10:1 ratio tended to have less sugar, sodium, and trans fats than those that didn’t.

“You aren’t alone if you are confused about whole-grain foods,” said Rebecca Mozaffarian, a project manager for the HSPH Prevention Research Center and first author of the study. She and her colleagues started this project when they realized there was little evidence-based information for guiding consumers, schools, and other organizations about choosing healthful whole grain foods.

The drawback to using a ratio is that you need to do a little math. The advantage is that the information needed is easily found on food labels, which list both total carbohydrates and fiber (see illustration). Divide the grams of carbohydrates by 10. If the grams of fiber is at least as large as the answer, the food meets the 1:10 standard. I find this a lot easier than reading through an ingredient list, which can be long and baffling (plus there are at least 29 different whole grains that can appear in the ingredients list).

In the nutrition label shown here, for example, one serving of this whole-grain roll has 23 grams of carbohydrate. Divide that by 10 and you get 2.3. It also has 5 grams of dietary fiber, which is definitely bigger than 2.3. That signals a healthful whole-grain food.

Why bother eating whole grains? They deliver everything an intact grain has to offer—fiber, vitamins, minerals, antioxidants, and other phytochemicals. As long as they aren’t overprocessed, the body digests them more slowly, which can delay hunger. And large, long-term studies have shown that consuming whole grains is one way to help reduce the odds of developing heart disease, diabetes, and other chronic conditions. They also taste better than processed grains.

Intact grains—wheat berries, oat berries, brown rice, quinoa, and the like—are the best source of whole grains. “They’re a slam dunk,” says Mozaffarian. Ground whole grains come next, as long as they still deliver a good dose of fiber and don’t also deliver added sugar, trans fats, or sodium. To find those, I’ll be using the 10:1 carbohydrate-to-fiber guide.