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."
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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