Meat eaters who defend their diets have been found to be more tolerant of social inequality.

Researchers from Lancaster University looked at the different ways people defend their carnivorous habits, with the vast majority fitting into at least one of four categories.

These were dubbed the four N's – Natural, Necessary, Normal and Nice. The researchers, publishing their study in the journal Appetite, carried out six studies to look at people's attitudes in relation to their meat consumption.

The four N's

Natural - "Humans are natural carnivores"

Necessary - "Meat provides essential nutrients"

Normal - "I was raised eating meat"

Nice - "It's delicious"

The first two tests showed between 83% and 91% of people fell into the four N's when justifying their meaty diets.

In another study, they found people who endorse the four N's tend to objectify animals and include fewer animals into "their circle of moral concern".

The remaining studies showed people who endorse the four N's are associated with a number of personal traits: "[They tend not to be motivated by ethical concerns when making food choices, are less involved in animal-welfare advocacy, less driven to restrict animal products from their diet, less proud of their animal-product decisions, tend to endorse speciesist attitudes, tend to consume meat and animal products more frequently, and are highly committed to eating meat."

Furthermore, the findings showed that those who "strongly endorsed" the four N's have less guilt about using animal products, suggesting they have a "guilt-alleviating function". They were also found to be more tolerant of social inequality.

Women were less likely to endorse the four N's, while those who did not tended to show greater concern for animal welfare.

Study leader Jared Piazza 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.

"One important and prevalent strategy is to rationalise that meat consumption is Natural, Normal Necessary and Nice. The four Ns are a powerful pervasive tool employed by individuals to diffuse the guilt one might otherwise experience when consuming animal products."