For a nation that loves its bratwurst and schnitzel, the message is not a welcome one. Germans have been urged to rethink their meat-eating habits if they want to help the planet.

Germany's federal environment agency has issued a strong advisory for people to return to prewar norms of eating meat only on special occasions and otherwise to model their diet on that of Mediterranean countries.

Germans are among the highest meat consumers in Europe, obtaining around 39% of their total calorie intake from meat and meat products, compared with 25% in Italy.

"We must rethink our high meat consumption," said Andreas Troge, president of the UBA, the government's advisory body on environmental issues.

"I recommend people return to the Sunday roast and to an orientation of their eating habits around those of Mediterranean countries."

Speaking on the sidelines of Berlin's Grüne Woche (Green Week), one of the world's largest agricultural exhibitions, he said agriculture was responsible for around 15% of Germany's greenhouse gas emissions and meat production was the most energy-intensive form of farming. With that in mind, he suggested that reducing meat consumption was a logical step forward.

"It hardly means sacrificing quality of life," said Troge. "I don't believe that the Italians are particularly unhappier than us as a result [of eating less meat]."

Troge's comments were criticised by farming experts and politicians. Edmund Geisen, agricultural adviser to the liberal Free Democrats, accused Troge of effectively calling for a boycott of German products. "Andreas Troge should stop trying to damage the nation's appetite by discrediting agricultural production," he said, calling his attack on meat "populist and one-dimensional". "Our enlightened consumers should decide for themselves what they want to eat."

Hilmar Steppat, of Germany's vegetarian association, VeBu, welcomed the move, saying: "It's good to see politicians are finally waking up to the fact that the amount of meat we eat is unsustainable." He added that although the number of vegetarians had increased from 0.4% in 1983 to around 10% today, Germans were still very big consumers of meat.

"Unlike in Britain, though interest in it is growing, vegetarianism here is still not widely practised," said Steppat. "The economic upswing after the war meant that people ate meat because it was a luxury. Before and after the war, people only ate meat about once a week, and maybe boiled some bones. Now it's normal to eat meat every day."

Meatless dishes are frowned upon, he added, and meat products such as goose liver pâté and veal - which are increasingly being regarded as unethical elsewhere - are widely available.

Troge cautioned that not only is meat production energy intensive, the methane gas emitted by cattle and the nitrous oxide produced by their dung, which farmers often leave in the fields from where it enters the atmosphere, also harms the environment.

Findings by the World Wildlife Fund also supports the claim that meat production is environmentally damaging. In its recent Living Planet report it said that a single kilogramme of beef requires 16,000 litres of water, taking into account a three-year lifespan for a cow, the grain it eats in its lifetime, and the water it drinks.

According to Destatis, Germany's federal statistics agency, meat consumption in the country has fallen from an annual 64kg (141lb) a head in 1991 to 58.7kg today. Health concerns are the main reason for the drop, it said.

According to VeBu, young women are particularly motivated by environmental concerns to give up meat.

"It's harder to get German men to do it," said Steppat. "For too many, eating meat is too closely connected with manliness."

Meat and heat

Meat production accounts for nearly a fifth of global greenhouse gas emissions, the UN Food and Agriculture Organisation estimates, though other experts believe that figure is too high.

In the UK food consumed by people accounts for nearly a fifth of national emissions, and meat and dairy products for just over half that, finds the Food Climate Research Network.

The high impact derives from the farmstock fodder grown with chemicals, transport fuels, and the potent greenhouse gas methane from belching cattle and sheep. The government estimates that, kilo-for-kilo, compared with bread, emissions linked to poultry farming are more than four times as high, to pork six times as high, and to beef and lamb 16 times. Besides this, tropical forest is cleared to allow feed-crops, also a source of emissions.

Compassion in World Farming says halving meat-eating would be more effective than halving transport use.