单选题 The disease, which attacks the brain and is always fatal, entered the food chain when cattle were fed the ground-up brains and spinal cords of slaughtered sheep and other animals contaminated with the disease. Fast food''s bad effect doesn''t end with fears of beef contamination. Critics in the U.S. also tag all those sacks of burgers and flies with helping to 【1】 another serious health problem: obesity. Currently about 44 million American adults are obese; another 6 million are 【2】 "super-obese"—more than 100 pounds overweight. The CDC found that in 1991, only 4 states had obesity 【3】 higher than 15 percent, but by last year the number had 【4】 to 31 states. In every state, obesity was increasing in all age 【5】 . And today''s teens, the agency says, are three times more likely to be overweight than teens in the 19【10】s. Though no study has yet established a 【6】 link between fast food and obesity rates, the expansion of fast-food chains 【7】 to be accompanied by rising waves of fat. In China, the number of overweight teens 【8】 . At the same time, similar weight 【9】 occurred in Japan and Great Britain 【10】 fast-food chains expanded in those countries.