It’s hard to refuse hamburgers, French fries and all of the other junk food. However, eating too much junk food can harm your body, particularly if you’re between the ages of 10 and 19.
“Junk food shapes adolescent brains in ways that harm their ability to think, learn and remember. It can also make it harder to control impulsive behaviors,” said Amy Reichelt, at Western University, Canada. “It may even increase a teen’s risk of discouraging and anxious feelings.”
Reichelt and two other researchers reviewed more than 100 studies, about how poor food choices can affect adolescent brains. They found adolescents are more sensitive than any other age group to processed foods with a lot of fat and sugar as their brains are not yet fully formed.
Adolescent brains are still developing the ability to judge risks and control actions. The prefrontal cortex is the part of the brain that tells us we shouldn’t eat chips all the time and helps us control that desire. However, this region doesn’t fully develop until we are in our early 20s.
Meanwhile, teen brains get more excited from rewards. 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 regions are even more sensitive when we are young. That’s because dopamine, a natural chemical that lifts our mood when we experience something good, is especially active in adolescent 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 the “teenage” mice that had a high-fat diet performed worse on memory tests than those eating a normal diet. Researchers said the high-fat diet may make the mice’s prefrontal cortex work less effectively.
So, _________________? The answer is exercise. When we exercise, the brain’s reward system becomes less sensitive to food. Exercise also helps the body to make a protein that helps brain cells grow and boosts connections between the prefrontal cortex and other brain regions. The prefrontal cortex thus can work better to help us make wise decisions and control our impulses.
【小题1】What is the purpose of the first two paragraphs?| A．To explain the dangers of junk food. | B．To analyze why junk food is hard to refuse. |
| C．To figure out what junk food is. | D．To show the connection between food and brains. |
| A．Their desire to take risks. | B．Their overactive brains. |
| C．Their still-developing prefrontal cortex. | D．The low level of dopamine in their brains. |
| A．what is the result of the experiment on mice |
| B．how does junk food affect adolescent brains |
| C．why do we need sensitive prefrontal cortex |
| D．what’s the best way to say no to junk food |
| A．Food for Thought | B．Exercise: the Best for Brains |
| C．Adolescent Brains | D．Healthy Food for Teens |
