英语听力精选进阶版 6358（在线收听）

If you love eating and have a gargantuan appetite, the idea of going on a diet might be hard to swallow.

Yet evidence suggests that short periods of fasting could help people lose weight and lead to better health. A lower calorie intake increases the life expectancy of mice, so could the same be true for humans?

Studies show that high levels of a growth hormone called IGF-1 can lead to accelerated ageing, whilst a low level can help prevent age-related diseases. Now evidence suggests the level of IGF-1 in our bodies can be lowered by what we eat.

It’s not only about eating less, but also about limiting the amount of protein we ingest. Research by Professor Valter Longo of the University of Southern California suggests that when the level of IGF-1 drops, our bodies switch from "growth mode" to "repair mode".

BBC journalist Michael Mosley went on the 5:2 diet, which involves eating normally for five days a week, then only consuming 600 calories for two days. Despite this reduced calorie intake two days a week, he didn’t crave more food on other days: "On my feed days I ate what I normally do and felt no need to gorge." However, he adds that "Current medical opinion is that the benefits of fasting are unproven and until there are more human studies it's better to eat at least 2000 calories a day. Fasting, like eating, is best done in moderation."

For those who want to reduce their weight whilst maintaining a varied diet, fasting for short periods of time might be healthier than crash diets or yo-yo dieting. However, others might decide they have enough on their plate without having to think constantly about what they eat. Either way, information about fasting provides food for thought.

Quiz 测验

1. What happens to mice when they consume fewer calories?

Mice that consume fewer calories live longer.

2. Why is it better to have a low level of the growth hormone IGF-1?

A high level of IGF-1 can make us age more quickly, whereas a low level of IGF-1 can be protective and help prevent age-related diseases.

3. Which verb in the article means "to really want to eat something"?

To crave. It can also be used as a noun: if you have "a craving" for chocolate, it means you really want to eat chocolate.

4. Why should we be careful when fasting?

We should be careful because the benefits of fasting are unproven.

5. What is the name of a diet that makes someone's weight go up and down?

Yo-yo dieting. This is what we call diets that don't lead to long-term weight loss, so a person's weight fluctuates.

Glossary 词汇表

a gargantuan appetite 惊人的食欲

to go on a diet 节食

hard to swallow 难以接受

to fast 禁食，斋戒

calorie intake 卡路里摄入量；热量摄取

age-related disease 老化伴随病

protein 蛋白质

to ingest 摄取，吸收

to consume 消耗

to crave 渴望

to gorge 狼吞虎咽

in moderation 适量的，有节制的

a varied diet 一个均衡多样化的饮食

a crash diet 速成食疗

yo-yo dieting 悠悠球式减肥（指节食后达到体重减轻，但过一段时间体重增加又要节食的循环）

to have enough on one’s plate 一个人已经有很多令人操心的事情要处理

food for thought 令人深思的东西或话