必威体育精装版高考五年英语真题分类汇编20 阅读理解（社会生活类）（原卷word版）.doc

必威体育精装版高考五年英语真题分类汇编 专题20 阅读理解（社会生活类） 1.C【2020·江苏卷】 For those who can stomach it, working out before breakfast may be more beneficial for health than eating first, according to a study of meal timing and physical activity. Athletes and scientists have long known that meal timing affects performance. However, far less has been known about how meal timing and exercise might affect general health. To find out, British scientists conducted a study. They first found 10 overweight and inactive but otherwise healthy young men, whose lifestyles are, for better and worse, representative of those of most of us. They tested the men’s fitness and resting metabolic (新陈代谢的) rates and took samples (样品) of their blood and fat tissue. Then, on two separate morning visits to the scientists’ lab, each man walked for an hour at an average speed that, in theory should allow his body to rely mainly on fat for fuel. Before one of these workouts, the men skipped breakfast, meaning that they exercised on a completely empty stomach after a long overnight fast (禁食). On the other occasion, they ate a rich morning meal about two hours before they started walking. Just before and an hour after each workout, the scientists took additional samples of the men’s blood and fat tissue. Then they compared the samples. There were considerable differences. Most obviously, the men displayed lower blood sugar levels at the start of their workouts when they had skipped breakfast than when they had eaten. As a result, they burned more fat during walks on an empty stomach than when they had eaten first. On the other hand, they burned slightly more calories (卡路里), on average, during the workout after breakfast than after fasting. But it was the effects deep within the fat cells that may have been the most significant, the researchers found. Multiple genes behaved differently, depending on whether someone had eaten or not before walking. Many of these genes produce proteins (蛋白质) that can improve blood sugar regulat