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.

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.

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.

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.

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

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.

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