单选题 Many people have been keeping on diet in the belief that cutting fat automatically cuts the risk of heart disease and cancer, too. Not so, says research published last week in the Journal of the American Medical Association. Women who trimmed the fat from their diets were just as vulnerable to colon cancer, breast cancer, and heart disease as women who did not.
The message? A low-fat diet isn"t equivalent to a healthful diet, says Marcia Stefanick, a physiologist at Stanford University"s Prevention Research Center, who helped run the government-sponsored study. Some 49,000 women between age 50 and 79 were divided into two groups and followed for an average of about eight years as part of the Women"s Health Initiative. One group was instructed to cut fat intake to 20 percent of total calories and to eat at least five daily servings of fruits and vegetables and six of grains. The other women were left to eat as they pleased. In the end, both groups had about the same occurrence of colorectal cancer, stroke, and heart disease. A slight difference in the rate of breast cancer among the lower-fat-diet women might be explained by chance alone.
There is hardly a green light to go on a junk-food binge, though, researchers" caution. For one thing, the women on the diet didn"t hit their target; they whittled fat intake just to 29 percent—from about 35 percent—by the end of the sixth year of the study. Moreover, the recommended diet made no distinction between "good" unsaturated fats and "bad" saturated fats and trans fats, whose importance to heart health has been recognized since the data-gathering started. And since all the women in the study were eating fairly healthfully beforehand, it"s possible that the small changes in vegetable and grain consumption by the dieting group weren"t big enough that any benefits registered. Rather than focus on total fat intake, Stefanick advises, go easy on foods containing saturated fats and trans fats and eat more vegetables and fruits and whole grains.
Long-term health may depend more on achieving a healthy body weight and getting regular exercise than on cutting out fat, says Tim Byers, an epidemiologist at the University of Colorado Health Sciences Center in Denver. Overweight people who "lower fat but don"t control calories can only make tiny changes to their chronic disease risk," he says. Until the links between disease and diet are fully understood, there are other ways to protect yourself: Get your cholesterol and blood pressure checked, and schedule that colonoscopy and mammogram. "No matter what you eat," says Byers, "a long life means knowing early where the problems lie."

单选题 We learn from the first paragraph that ______.

单选题 In Para. 2, it seems that the difference in the rate of breast cancer might be ______.

单选题 Stefanick advises that ______.

单选题 Which of the following is NOT one of the ways to achieve long-term health according to Tim Byers?

单选题 Byers seems to indicate that ______ is vital to a long life.