Women who favor whole grains over white bread and other refined grains gain fewer pounds as they age. Harvard researchers looked at 74,000 women aged 38 to 63. In the 12-year study, they found those who consistently ate more fiber-rich whole grains gained less weight than women who didn’t. This may be because whole grains are high in satisfying fiber, but Simin Liu, assistant professor of medicine at Harvard Medical School in Boston and lead author of the study, has another theory. “Whole grains may contain enzymes that force the body to burn extra calories during digestion,” he says. To reap the rewards, dish up whole wheat breads, oatmeal, brown rice, and whole-grain breakfast cereals.