In the United States, those businesses which are based on the suffering of animals promote their interests through PR agencies and lobby groups. One of the aims of this PR is to persuade people that concern for animal welfare is, first of all, a radical issue that would only be of interest to lunatics and, second, in conflict with a "more important" need to care about humans.

If all your friends abuse their children, and you don't, you are the one who is radical. If you live in a society where it is legal to test an oven cleaner by putting it in a rabbit's eye - but it is illegal to have sex in certain positions - yes, you are the dangerous radical if you think this is wrong.

But the second objection to concern about animals seems, on the surface, more rational. Many people who have never in their lives done anything to help their own species are outraged when somebody expresses concern for the welfare of another "inferior" one. ("Why are you giving money to the gypsies? There are so many Czech people that need help!")

The truth is that concern for humans almost always goes hand in hand with concern for other species. Survey after survey has shown that people who care the most about animal rights also have the most liberal views on human rights. Conversely, sadists and psychopaths invariable turn out to have had a history of abusing animals.

The two needs work together in a much more practical sense, as well. If you are one of these self-righteous objectors to animal rights who wants to "put people first" perhaps you should become a vegan.

No doubt you couldn't care less about animals suffering in factory farms. Indeed, perhaps, at heart, you are a sadist, who actually gets off from thinking about this cruelty - so you want to do your best to promote it. Maybe you are a Christian, and you believe that it is "God's will" that you have dominion over the other animals. Or maybe all you care about is your own fat guts and the fat guts of your fellow humans. Well, if that's what you are worried about, you should definitely become a vegan.

The single best thing you can do to help your fellow humans is to stop eating dead animals. A given area of land can support one meat-eater on a typical US diet; or ten vegetarians, or twenty vegans. In the United States, 90% of the agricultural land (and two thirds of all the arable land) is used, directly or indirectly, to produce dead animals or cow secretions. Although water is in short supply in many states, it is often subsidized to farmers. Half of all the water used in the US is used in the dead-animal industry, mainly to irrigate crops used for feed.

However, outside the white parts of the world, not everyone has enough to eat: according to the World Health Organization two billion people are suffering from one or other form of malnutrition:

Some 49% of the 10 million deaths among under-five children each year in the developing world are associated with malnutrition, ... . iodine deficiency is the greatest single preventable cause of brain-damage and mental retardation world-wide, ... and vitamin A deficiency remains the single greatest preventable cause of needless childhood blindness.

A single person in a Western society who switches to a vegan diet releases the land and water resources to feed twenty people. The equation is not as simple as that, of course: a major reason for human malnutrition is distribution, rather than lack of food. Nevertheless, according to the Overseas Development Council, if Americans were to reduce their meat consumption by only ten percent it would free enough grain to feed 60 million people.

So the next time you're in McDonald's, biting into your dead cow, spare a thought for all the dead humans in Africa.