Within 10 years, nearly half of American adults will be obeseor very overweighta new report predicts. In addition, the researchers warned that one in four Americans will be severely obese. The new report used a federal study that lasted more than 20 years and included data from 6.3 million adults. The researchers made predictions for the future based on current trends. Their study corrects for a weakness in earlier studies. Before, research usually depended on national health surveys in which people often reported their weight as less than it really was. “It’s alarming,” said nutrition expert Dr. Lawrence Appel of Johns Hopkins University. He was not involved in the study. “We’re going to have some pretty awful problems” medically and financially because so many people weigh too much.