The unhealthy ingredients and low nutrition content of the food can make you less active a

nd lazy, new research shows. No surprises there.【C1】______, what is more shocking is that the energy-weakening effects of a junk food diet can persist,【C2】______after you switch to a healthy【C3】______. Two groups of female rats were fed different diets by researchers for a six-month period. One group ate unprocessed foods such as corn and fish meal【C4】______the other ate a diet【C5】______to imitate junk food; high in sugar, and lower in【C6】______. While understandably the group eating the junk food diet gained more weight than the other, they also【C7】______from fatigue and became less active and less【C8】______—ie: lazier. In fact, those rats fed junk food took twice as many, and longer breaks during tasks than the rats eating a healthy diet, even tasks which【C9】______rewards. What is even more【C10】______is that switching these rats back onto a nutritious diet at the end of six months for nine days didnt seem to reverse their weight gain or their learnt laziness. This could suggest that while an【C11】______case of bad food—say on holiday, will not have too much of a【C12】______effect if you generally eat a good diet and lead a healthy lifestyle. But those who eat a poor diet【C13】______the long term may actually become lazy and fatigued, as well as gaining weight and suffering the health consequences【C14】______being overweight. The research shows that switching【C15】______a healthy diet in the short term is unlikely to be【C16】______to reverse any of the side effects of a diet high in junk food. "Overweight people are often regarded as lazy and lacking【C17】______," says Blaisdell, a professor of psychology at UCLA "We【C18】______our results as suggesting that the idea commonly【C19】______in the media that people become fat because they are lazy is wrong. Our data suggest that diet-induced obesity is a cause,【C20】______an effect, of laziness. Either the highly processed diet causes fatigue or the diet causes obesity, which causes fatigue."

【C1】

A．Meanwhile

B．Therefore

C．However

D．Moreover