[填空题]Obesity Epidemic
Ask anyone why there is an obesity epidemic and they will say that it’s all down to eating too much and burning too few calories. That is undoubtedly true. But it’s also true that we live in an "obesogenic (肥胖基因的) environment": calorific food is plentiful and cheap and our lifestyles are increasingly sedentary.
Now, obesity researchers are increasingly dissatisfied with such explanations. They believe that something else must have changed in our environment to cause such dramatic rises in obesity over the past 40 years or so. Nobody is saying that the "big two" -- reduced physical activity and increased availability of food -- are not important contributors to the epidemic. But they cannot explain it all.
Earlier this year a review paper by 20 obesity experts set out the 9 most plausible alternative explanations for the epidemic. Here they are.
Not Enough Sleep
It is widely believed that sleep is for the brain, not the body.