Despite greater awareness of exercise and healthy foods, many Americans remain ``significantly overweight,'' according to federal researchers who say most government nutritional goals are unlikely to be met. ``Everybody knows what is required to lose weight, yet the prevalence of overweight doesn't seem to change much,'' said Dr. Marion Nestle of the U.S. Office of Disease Prevention and Health Promotion in Washington. The national Centers for Disease Control, in Atlanta, reviewed the progress toward the government's 15 top-priority goals for American nutrition in 1990, including raising public knowledge of the effects of salt and lowering average blood-cholesterol levels. ``Substantial progress'' has been made in several areas, and three of the goals will be fully met, researchers said. But despite the progress, Americans will probably fall short of eight major goals, including that of getting people to lose weight, said Ms. Nestle, whose office helped prepare the report. ``The research that relates (poor) diet to disease is now incontrovertible,'' she said. ``It's really time now to start looking at ways to implement the recommendations that everybody is familiar with _ ways to improve the nutritional status of the population.'' The goals that will likely not be met, she said, are: _ Having less than 10 percent of American men and 17 percent of American women over the ``significantly overweight'' level, defined as more than 20 percent over desired weight. _ Having 50 percent of the overweight population on a weight-loss program combining diet and exercise. The CDC said recent surveys show half the nation's overweight people are indeed trying to lose weight _ but only half are using both diet and exercise. _ Cutting the average adult level of harmful serum cholesterol below the 200 count. In a 1976-80 survey, average cholesterol levels were 211 for women and 215 for men, down from 214 and 217 in 1971-74. ``That rate of decline is not as fast as it should be,'' Ms. Nestle said. _ Having at least three-fourths of all mothers breast-feeding their babies at the time they leave the hospital. A 1984 survey put the figure at 61 percent, up from 45 percent in 1978. _ Having all packaged foods labeled with ``useful calorie and nutrient information.'' Such is the case in 55 percent of packaged foods, up from 42 percent in 1978, Ms. Nestle said. _ Including nutrition education in the required school curriculum in all states. By 1985, only 12 states had such a requirement, the CDC said. The three objectives that researchers think will be fully met, she said, are: _ Having more than 75 percent of the population aware of nutritional risks for conditions such as heart disease and high blood pressure (fats and salt) and tooth decay (between-meal sweets). Awareness already runs as high as 90 percent in some categories, the CDC report said. _ Having 90 percent of U.S. adults aware that to lose weight they must eat fewer calories or increase physical activity, or both. The percentage was 73 in 1985 and is rising quickly, Ms. Nestle said. _ Implementation of a comprehensive national nutrition status monitoring system. It is already in place, the CDC reported.