题目内容：

Sticking to a vegan（纯素食的）diet might sound difficult. 1. According to Huffpost, more than 3 million people in the US are vegans. And in the UK, about 542,000 people turned vegan during the last decade.

2.

One reason could be that people want to reduce greenhouse gas emissions（排放）. 3. In fact, it’s believed to account for 18 percent of the world’s greenhouse gas emissions, according to a 2013 study by the UN Food and Agriculture Organization. This amount is even greater than that of all the world’s cars, trains and planes combined.

A growing number of people are also starting to believe that it’s wrong to kill animals for food. Therefore, some of them made an ethical（道德的）choice to become vegan.

4. Vegan celebrities often use social media to spread the message of veganism and share tips on how to live a vegan lifestyle.

But experts also want to remind people that meat is important for our health. 5. So, if you’re thinking about becoming vegan, you should do some research before making your decision.

A. Meat production is very bad for the environment.

B. So why exactly has veganism become so popular?

C. It is up to you to decide whether to go vegan or not.

D. Social media is also believed to be behind the increase in veganism.

E. Fresh fruits and vegetables, grains and nuts are all key to a vegan diet.

F. But in recent years, veganism has become a popular lifestyle in many places.

G. They say that a strict vegan diet may not offer everything that the human body needs.