A recently-published study found that people who eat the most whole-grain foods also eat a generally healthier diet than the rest of the population. The problem is, very few people eat even one serving of whole grains per day.

In 2005, Dietary Guidelines for America first specified that people in the U.S. should eat three servings of whole grains per day. This doesn't seem to be happening.

Whole grains are grains where the outer hull and inner germ has not been stripped away during processing. The hull contains fiber and vitamins, while the germ contains antioxidants and other vitamins.

According to the Whole Grains Council, 40% of U.S. teenagers don't eat any whole grains.

Many studies have shown that eating whole grains is associated with a lower risk of obesity, heart disease, type 2 diabetes and even certain types of cancer.

So why aren't people eating more of them?

Carol O' Neil, first author of the study, thinks that people may be afraid of them, afraid that they won't like them. But they might if they had a bit more exposure to them.

When interviewed by Reuters Health, O'Neil commented that people who shy away from whole grain foods would probably like some of them if they just tried them. After all, almost everyone likes popcorn, even though few realize that it's a whole grain.

Whole grains are grains where the outer hull and inner germ has not been stripped away during processing. The hull contains fiber and vitamins, while the germ contains antioxidants and other vitamins. What remains in processed grains, such as white rice, is essentially naked starch.

All grains — wheat, rice, corn, etc. — start out as whole grains. But by the time they reach the consumer, the grain in many foods has been processed and stripped of much of its nutritional value.

In O'Neil's study, less than 5% of the people between the ages of 19 and 50 reported eating three or more servings of whole grains daily.

The study used data from the 1999-2004 National Health and Nutrition Examination Survey. This included 7,031 adults aged 19-50 and another 6,237 adults 51 or older. The younger group ate less than two-thirds of a serving of whole grains daily, on average, while the older people ate just over three-quarters of a serving. But the individuals who ate the most whole grains also had a healthier overall diet — more fiber, healthy fats, and vitamins and minerals, while eating less sugar, unhealthy fat, and cholesterol.

The study can't show that the people who ate the healthier diet were actually healthier than the other study members. But there's plenty of evidence from other studies that eating a healthier diet translates into many health benefits.

The study was conducted in 2004, before the "three servings a day" guideline was in effect. But O'Neil doubts that people's diets have changed much since 2004.

Because many manufacturers would like to portray their food products as containing whole grains even when they don't, interpreting food labels can be tricky. After all, few people know what degerminated yellow corn meal is (it's corn meal with the inner germ removed and is not a whole grain). Whole wheat on a food label means whole grain; wheat on a food label may or not mean whole grain. And labeling of foods that contain two or more grains is especially tricky.

That's why the whole grain stamp was developed.

There are now two whole grain stamps that appear on foods. The 100% Stamp means that a food contains at least one full serving of whole grain per serving size and that ALL the grain is whole grain. Foods with the basic Whole Grain Stamp contain at least half a serving of whole grain per serving size.

The Whole Grains Council website explains more about whole grains and whole grain foods: why they're healthy, where to find them and how to understand product labeling. They also feature recipes. People interested in finding out more about whole grains may want to check out the government's MyPlate website.

How can you tell that you don't like whole-grain foods if you don't try them?

An article detailing the study results was published in the October 2010 issue of the Journal of the American Dietetic Association.

Carol E. O'Neil, Ph.D. is a professor of Human Nutrition and Food in the School of Human Ecology at Louisiana State University.