It’s hard to say no to hamburgers, French fries and all of the other junk food. However, eating too much junk food can harm your body, especially if you’re between the ages of 10 and 19. “Junk food shapes teenage brains in ways that harm their ability to think, learn and remember. It can also make it harder to control impulsive (冲动的 ) behaviors,” said Amy Reichelt, at Western University, Canada. “It may even raise a teen’s risk of mental (精神上的) problems.”
Reichelt and two other researchers reviewed more than 100 studies, about how poor food choices can affect teenage brains. They found teenagers are more sensitive (敏感的) than any other age group to foods with a lot of fat and sugar as their brains are not yet fully formed.
Teenage brains are still developing the ability to notice risks and control actions. The prefrontal cortex (前额皮质) is the part of the brain that tells us we shouldn’t eat chips all the time and helps us control ourselves. However, this part doesn’t fully develop until we are in our early 20s.
Meanwhile, teen brains get more excited from rewards (奖励). The parts of the brain that make us feel good when we do something enjoyable — like eating tasty foods — are fully developed by the teen years.
In fact, these parts are even more sensitive when we are young. That’s because dopamine (多巴胺 ), a natural chemical that makes us feel happy when we experience something good, is especially active in teenage brains.
Therefore, the teen brain has two attacks against it when it comes to saying no to junk food. “It has an increased drive for rewards and reduced self-control,” said Reichelt.
Reichelt and her team did their own study using mice, whose brains develop much like our own. They discovered that “teenage” mice that had high-fat foods performed worse on memory tests than those eating normal foods. Researchers said the high-fat foods may make the mice’s prefrontal cortex work less effectively.
So, what’s the best way to say no to junk food? The answer is exercise. When we exercise, the brain becomes less sensitive to food, besides this, it also helps our brains grow and become better able to make wise decisions and control our behaviors.
【小题1】What does the first paragraph mainly talk about?| A．What problems are caused by junk food. |
| B．What junk food teenagers like most. |
| C．How junk food harms teenage brains. |
| D．How junk food shapes teenage brains. |
| A．Teenagers are less sensitive than any other age group to junk food. |
| B．Junk food may make people’s prefrontal cortex work less effectively. |
| C．Dopamine helps our brains become better able to make wise decisions. |
| D．The prefrontal cortex makes us happy when we do something enjoyable. |
| A．Teenage Brains | B．Healthy Food for Teenagers |
| C．Food for Thought | D．Exercise: the Best for Brains |
