Foods labeled 7-grain or multigrain may seem like the healthiest choices—especially with new findings showing that a diet rich in whole grains protects against heart disease, cancer, and other ills.

Unfortunately, many foods are only posing as rich in whole grains. "Take a closer look at the labels and you may find there's not a single whole grain in them," says Cynthia Harriman, director of food and nutrition strategies for the Whole Grains Council, a nonprofit consumer group in Boston.