Just mention the word vegan or vegetarian and the insults fly. Vegetabilists, plant nazis, salad munchers, eco-warriors, hippy dippy morons, bunny huggers. hese from the meatarians - is that an insult or a proudly worn moniker? Carnivores versus Vegans. Light the blue touchpaper. You could start a riot! Why such outrage?
Ethical vegans reject the use of animals for any purpose. Dietary vegans abstain from eating any animal products whatsoever. To environmental vegans animal production is environmentally damaging and unsustainable.
When vegans defend their viewpoint they give no quarter. Their message is clear. To eat a meat-based diet is bad and by implication those who eat meat are bad too. Even many of those who live on a plant-based diet know the vegan message sounds self-righteous, self-satisfied, joyless, morally superior - extreme even. But not all vegans are hippy dippy. You could pass some in the street and not even guess. Nevertheless their opinion is clear, and they act on it.
But when meat eaters are challenged their message is plain but their actions contradictory. Take cruelty. Most people are repulsed by the deliberate infliction of pain. Nevertheless most of us still go for the cheapest option - bog standard supermarket meat - knowing that prices can only be kept this low by mass production, a system that rears animal with such brutal efficiency that a heartless lack of compassion becomes unavoidable.
Those who choose a meat-based diet also claim humans need animal protein. We all like studies that suit our prejudices and it is easy to find them. But some studies do seem definitive. Like The China Study, published in 2006 which claims to be the most comprehensive study ever undertaken of the relationship between diet and the risk of developing disease. Its findings show that people who ate the most animal-based food got the most chronic disease and that those who ate the most plant-based foods tended to avoid chronic disease. A similar conclusion was reached by A Harvard study - 'Red Meat Consumption Linked to Increased Risk of Total, Cardiovascular, and Cancer Mortality'. Published this March it examined 37,698 men over 22 years and 83,644 women for up to 28 years.
But there are also environmental reasons for a plant-based diet. The world population, now 7 billion, is predicted to reach 10 billion by the end of this century and could, potentially, reach 28 billion by 2150. Given climate change, the destruction of ecosystems, the pressure on food and water supply - something will have to give. Population control? A reduction in transport, energy, food, water? Of these the most practical - easier than cutting down on transport or depending on technological fixes to provide energy or a revolution in birth control - seems to be change to a plant-based diet.
There are a raft of figures to show the waste involved in livestock production. 30% of the world's land is used to raise animals and animal-feed crops. 1 kilo beef takes 12 times more water to produce than one kilo of wheat; 15 times more land than one kilo of cereals and 70 times more than 1 kilo of vegetables. Broiler chickens put on 1 kilo of body weight for 1.6 kilos of feed (called the food conversion ratio or FCR). The FCR for farmed Atlantic salmon is 3 to 1; for pigs 4 to 1; for lamb and beef between 7 to 1 and 9 to 1. Even if the accuracy of these figures is a little flaky (everyone knows figures are spun to suit a particular purpose) it is clear that feeding plants or fish to animals rather than eating plants directly is hugely, massively, wasteful.
Add to this the widespread pollution of land, water and air caused by factory farming; the destruction of vast tracts of the seabed from trawling for fish (about one third of wild caught fish is made into fishmeal to feed farmed animals and farmed fish) and the depletion of fish stocks. And climate change - there is a stack of reports that show the livestock industry contributes more to the greenhouse effect than cars: 18% compared to 15% for transportation.
Cruelty. Poor health. Environmental degradation. Competition for food and water. Each factor on its own seems reason enough to change from a meat-based diet to a wholly plant-based diet. Vegans are often associated with idealism. Yet maybe it is they who are the realists. But put this to those who choose a meat-based life-style and the sparks fly. Sound logic and a reasoned defence seem to go up in flames. And the insults fly: Vegetabilists! Plant nazis! Bunny huggers!