Meat eaters care less about social inequality than vegetarians and adopt a rationalising strategy to feel less guilty about their diet, say psychologists.

Researchers found that people often resort to the “4Ns” to defend the use of animals for food, viewing meat consumption as “natural, normal, necessary and nice”.

Jared Piazza, from the University of Lancaster, who led the international study, said: “The relationships people have with animals are complicated. While most people enjoy the company of animals and billions of dollars are spent each year on pet care and maintenance, most people continue to eat animals as food.

“People employ a number of strategies to overcome this apparent contradiction in attitude and behaviour.”

The scientists conducted a survey in which they asked students and adults in the US why they thought it was okay to eat meat.

The most commonly expressed argument was that it was “necessary” because meat provides essential nutrients.

Consuming the flesh of animals was also said to be “natural” because humans are “natural carnivores”, “normal” because “I was raised eating meat”, and “nice” because meat is “delicious”.

Men endorsed the 4Ns more than women, while people who rejected them showed a greater concern for animal welfare.

Participants who said meat-eating was natural, necessary, normal and nice also shared other characteristics, said the researchers. For instance, they regarded cows as less intelligent and were more tolerant of social inequality.

Piazza said: “The 4Ns are a powerful pervasive tool employed by individuals to diffuse the guilt one might otherwise experience when consuming animal products.”

The research is published in the journal Appetite.