【推荐1】Not long ago, people could only buy organic food in small shops. Today it is common in most major supermarkets. The reason for the increase is that more and more people are demanding food grown without chemicals. Since the 1990s, organic farm production has gone up continuously. This pattern is expected to continue around the globe.

Australia leads the world in land used as for organic agriculture. It has four times as all of Asia. However, most of the land is not very fertile, and it only produces a modest amount of food. Argentina is a distant second, followed by Brazil, the United States and China. In Africa, only a very small amount of land is registered for organic farming. That does not mean Africa relies on chemicals. In fact, many farmers do not use chemicals because they cannot afford them. Yet there are no programmes for these farmers to prove they do not use chemicals. Without these programmes their food can never be approved organic.

India has had the most dramatic recent increase in organic farming. Like many other countries, India sees continual growth in organic food sales around the world. This, of course, leads to growth in profits. Sales of organic food were more than doubled from 2000 to 2005. Like India, many countries are trying to increase commercial organic farming to get a share of the sales. This has led to criticism. Some people believe that organic farming should not just be about making money. They think the goal is to help the environment. Others say organic farming will not continue if it is not profitable. They say that people should be able to make money while providing healthy food for mankind.

【推荐3】If only things were that simple. Supporters of the so-called Stone Age diet argue that farming practices introduced about 10,000 years ago are harmful to human health, and that we shouldn't eat grains or food made from milk such as butter and cheese. Instead, they say, we should only eat plenty of lean meat (瘦肉) and fish, with fruit and raw vegetables on the side.

The idea, also called the caveman, or hunter-gatherer diet, has been around for decades and was discussed at a meeting of the British Society for Allergy, Environmental and Nutritional Medicine.

According to Lauren Cordain, a nutritionist at Colorado State University who presented the idea to the meeting, those following the meat-centered menu “lose weight and get healthy by eating the food you were designed to eat”. He says there is increasing evidence that a caveman diet can prevent and treat many common western diseases. Studies of islanders in Papua New Guinea who still live a hunter-gatherer lifestyle show they rarely suffer from heart disease.

But other nutritionists argue that cutting out whole food groups such as grains is just not a good idea.

“I would recommend anybody to eat lean meat and raw vegetables,” says Toni Steer of the MRC human nutrition research unit at Cambridge. But what you're asking people to do is cut out a food group which is good for your health.

Archaeologists say it's not even clear exactly how much of the various foods people actually ate during the Stone Age.

“There was no one Stone Age diet; diets of the past varied greatly,” says John Gowlett, an archaeologist at the University of Liverpool who also attended the conference. Prehistoric people in Africa probably ate less meat than many people think, he says, while those in the northern, icy areas were forced to eat only whatever animals they could catch.

“I'm not convinced that we know what Stone Age man ate,” agrees Andre Millard, who researches ancient health and diet at Durham University. “The evidence we have only suggests the meat component of the diet. We get bones from animals they have eaten but we don't get the remains of any vegetables they have eaten because they rot (腐烂) away.