If your four-person family skips meat and cheese one day a week for a year it’s the equivalent of taking a typical car off the road for five weeks.

People following a vegetable diet have lower rates of a number of health problems, including excess weight and obesity, cardiovascular disease, hypertension, type 2 diabetes, some cancers, gallstones, kidney stones, constipation and diverticular disease.

It takes up to 13 kilos of grain and 16,000 litres of water to produce 1 kilo of meat.

A number of studies have found that people who eat vegetarian diets have lower rates of chronic disease and often live longer than those on predominantly meat-based diets.

Cutting out meat and dairy can markedly reduce your intake of fat, especially saturates. Even extra lean minced beef has over four times the fat of pulses.

A healthy diet should include 7-10 portions of fruit and vegetables a day.

Vegan diets are usually higher in fibre, magnesium, folate, vitamins C and E, iron and phytochemicals, while tending to be lower in calories, saturated fat and cholesterol.