Good nutrition is important throughout life, but it takes on special significance through your later years.

"All the nutritional things that we need to be concerned about as younger adults are even more important as we get older," says Alice Lichtenstein, professor of nutrition at Tufts University.

That's because starting in middle age (40 to 65), the body begins losing about 1 percent of muscle per year. Fat replaces the lost muscle. Since fat cells need fewer calories than muscle cells to survive, metabolism slowly declines. Add to that the inactivity that often occurs with aging and the bottom line is that you need to eat fewer calories -- or risk expanding with age.

What makes it trickier is that the requirements for essential vitamins and minerals stay the same, and a few increase, with age. That means it takes very wise food choices to avoid falling short on nutrients that control blood pressure, promote heart health, digestion, immunity and blood clotting.

To help guide older adults -- and those who care for them -- Lichtenstein and her colleagues at Tufts have crafted a modified food pyramid. While it is designed for those 70 and older, its messages are good for all ages and are meant to be used in conjunction with the U.S. Department of Agriculture's Food Pyramid ( This week the USDA launched My Pyramid Menu Planner (, an interactive tool to help make smart food choices easier.

The foundation of the pyramid for older adults is physical activity. There's clear evidence that staying active delays moderate to severe physical changes that begin in middle age. But even for those who have been sedentary, the latest research suggests that it's never too late to start moving.

"Older adults can improve physiologic capacity -- aerobic, strength and balance -- with targeted exercise at any age," Miriam Nelson, another Tufts researcher, recently reported to the Physical Activity Guidelines Advisory Committee. (The Department of Health and Human Services convened the committee to write the first set of national physical activity guidelines, which are slated to be issued later this year.)

'Lifestyle' exercises

The recommendations for older adults highlight so-called lifestyle exercises, from walking the stairs to doing yardwork and housecleaning. "You don't have to join a gym," says Lichtenstein, who climbs stairs each time she does her laundry.

(For those whose knees may not be up to climbing stairs, Mayo Clinic researchers recently reported that age alone should not deter those who need surgery to repair the anterior cruciate ligament in the knee. The study of nearly three dozen patients, age 50 to 66, found that 83 percent who underwent such repair were able to return to normal or near normal activities and participate again in sports.)

For the special nutritional needs of advancing age, it's important to eat foods rich in calcium, potassium and vitamins D, E and K. Federal food surveys show that many older Americans fall short on these nutrients.

The modified pyramid urges consumption of whole grains and beans, which are both rich in fiber. It also advises eating more bright-colored vegetables, such as carrots and broccoli, and consuming plenty of deep-colored fruit, including blueberries, strawberries and melons. Seniors are urged to consider frozen as well as canned fruit and vegetables, which have a longer shelf life, require no peeling or cutting, and are often more economical.

The pyramid for seniors also emphasizes eating plenty of low-fat and nonfat dairy products -- as well as juice and cereal fortified with calcium -- to help boost intake of this key mineral that helps maintain healthy bones, hearts and blood pressure. And the pyramid urges drinking plenty of fluids -- especially water. Current recommendations from the Institute of Medicine are 12 cups per day (beverages and food) for women 70 and older; 16 cups for men the same age.

Sodium is also a concern for seniors and other Americans. Adequate intake for adults 51 to 70 is 1,300 milligrams per day; 1,200 for those 71 and older. That's about 1,000 milligrams less than what most seniors are consuming according to government surveys.

So take note, baby boomers. Each hour, 300 boomers turn 60, according to the Census Bureau. You'll soon be pushing 70, too.

You can subscribe to the free Lean Plate Club e-mail newsletter at Sally Squires is a writer for the Washington Post.