The following article comes from the U.S. News ebook, How to Live to 100, which is now available for purchase.
If your mental image of an older person is someone frail and thin, it may be time for an update. For the generation currently moving through middle age and beyond, a new concern is, well, growing: obesity. Government figures show that Americans in their 60s today are about 10 pounds heavier than their counterparts of just a decade ago. And an even more worrisome bulge is coming: A typical woman in her 40s now weighs 168 pounds, versus 143 pounds in the 1960s. "People used to start midlife [at a lower weight] and then lose weight when they got into their 50s, but that doesn't happen as much anymore," says David Kessler, former commissioner of the Food and Drug Administration and author of The End of Overeating.
If you're entering that danger zone now, be aware that it's not going to get any easier to lose weight, because people need fewer calories as they age. Blame slowing metabolism and the body's tendency starting in midlife to lose muscle mass—a process known as sarcopenia—and gain fat, especially around the abdomen. (Fat burns fewer calories than does muscle.) "All that conspires to make it harder for people to maintain the same body weight when they eat their usual diets," says Alice Lichtenstein, director of the cardiovascular nutrition laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. "People have fewer discretionary calories to play with, so they need to make better food choices."
But paying attention to what you eat isn't only about controlling weight; the need for certain vitamins and minerals increases with age. One is calcium, necessary to protect bones. Another is B12, since some older adults make less of the stomach acid required to absorb the vitamin. More vitamin D also is required. "The skin gets less efficient at converting sunlight into this vitamin, so more is needed from other sources," Lichtenstein says. Fewer than 7 percent of Americans between ages 50 and 70 get enough vitamin D from the foods they eat, and fewer than 26 percent get enough calcium.
Eating right and staying lean are both crucial for maintaining health throughout the years. Carrying an extra 20 or 30 pounds with you into old age doesn't bode well for attempts to head off the myriad diseases that strike in midlife and later and are linked to weight—including diabetes, arthritis, heart disease, and some forms of cancer. If weight is a problem, it is especially important to limit processed foods that combine sugar and fat. Studies with rats indicate that when the two are added to chow, animals can't easily stop eating, says Kessler. This happens in humans, too, he says, and food manufacturers have taken note and added sugar and fat to many products.
So what should people eat? A healthful diet at midlife is the same as for younger adults—it's just that the stakes may be higher. The focus should be on fruit, vegetables, whole grains, low- and nonfat dairy, legumes, lean meats, and fish. (While there is no single "longevity diet," a Mediterranean diet—similar to a conventional healthful diet but with more emphasis on fish and olive oil—has been tied to a decreased risk of heart disease and reductions in blood pressure and "bad" LDL cholesterol. Mediterranean dieters may also outlive non-followers by two to three years, research suggests.) For someone whose current diet is far from this ideal, Lichtenstein advises starting small: load more veggies on the dinner plate; eat more skinless chicken or beans in place of hamburger. (A singly daily serving of processed or unprocessed red meat may boost the risk of premature death, according to a recent study by Harvard School of Public Health researchers.) And exercise. Walking briskly for at least 30 minutes every day makes it easier to get away with the occasional cookie. With further fine-tuning of that basic healthful eating plan, you can greatly improve your odds of staving off the major barriers to a vital old age:
Heart Disease. By now, every American surely knows the roll call of foods that affect your heart, for better and for worse. Good for the ticker: monounsaturated fats like olive oil and the omega-3 fatty acids found in such cold-water fish as salmon and herring and in flaxseed and walnuts. Harmful: too much red meat and full-fat dairy, because of their saturated fat content, and margarine and baked goods, because of the trans fats they contain.
But expunging troublesome foods from your daily fare can be surprisingly difficult. "Although many supermarket products have removed the trans fats, they're hardly history. Restaurants, especially, continue to use them," cautions Robert Eckel, former president of the American Heart Association and a professor at the University of Colorado–Denver. Some food manufacturers, moreover, have simply swapped out their trans fats for saturated fat, which is equally problematic, Eckel says. Saturated fat should total no more than 7 percent of daily energy intake—about 16 grams for the average 2,000-calorie diet.
Research points to another potential heart danger: high-fructose corn syrup, commonly found in soda. The decades-long, 88,000-woman Nurses' Health Study found that, even controlling for weight and other unhealthful habits, drinking one 12-ounce can of regular soda daily boosts a woman's risk of later having a heart attack by 24 percent; two or more servings raise the risk by 35 percent.
Hypertension. Lowering high blood pressure before it contributes to the development of heart disease is vital for people in midlife. It can be accomplished with an eating plan known as the DASH (Dietary Approaches to Stop Hypertension) diet. "The DASH diet has the same effect as taking a blood-pressure-lowering medication," Eckel says. The plan is rich in fruits and vegetables (eight to 10 servings a day for someone on a 2,000-calorie diet), grains (six to eight servings daily, with most being whole grains), and low-fat protein sources. And it's low in saturated fats and added sugars. DASH also limits sodium to 2,300 mg a day or to an even lower 1,500 mg—just two thirds of a teaspoon.
Insulin Resistance. Research has repeatedly demonstrated that type 2 diabetes and insulin resistance (a precursor to the disease in which the body begins to respond less well to the hormone that clears glucose from the bloodstream) can often be prevented or postponed with a healthful diet, exercise, and weight loss. That three-part combination, in fact, actually has been shown to be more effective than medication. An eating plan aimed at minimizing the risk of insulin resistance does not have to be complex.
"I coach people to mentally divide their lunch and dinner plate into thirds, with one third protein, one third nonstarchy vegetables, and the final third a starch like brown rice, whole-wheat pasta, potatoes, or corn," says Nora Saul, a dietitian and diabetes educator at Harvard's Joslin Diabetes Center in Boston. It's also a good idea to get serious about cutting back on sugar and white flour, both of which have a high glycemic index and can spike blood glucose levels.
Joint disease. Although age is a risk factor for arthritis, the breakdown of cartilage in the joints is not inevitable. Minimizing weight gain goes a long way toward avoiding this problem, because every extra pound translates to 3 pounds of pressure on the knees while walking. It is also a good idea to limit foods that encourage inflammation in the body, particularly omega-6 fatty acids (found in corn and soybean oils and many snack and fried foods), according to the Arthritis Foundation.
Cancer. Some 45 percent of colon cancers, 38 percent of breast cancers, and 69 percent of esophageal cancers would never occur if Americans ate better, weighed less, and exercised more, estimates the American Institute for Cancer Research. The organization recommends limiting red meat to 18 (cooked) ounces per week and loading up on plant-based foods, which are high in the phytochemicals and antioxidants known to inhibit cancer cell growth in lab animals. Those with the deepest colors—like purple grapes, blueberries, and leafy green vegetables—tend to have the most beneficial compounds. One study, for example, showed that eating foods such as broccoli and kale that have lots of sulforaphane, an antioxidant, suppresses a bacterium linked to stomach cancer.
Updated on 5/22/12: This story was originally published on December 14, 2009. It has been updated.