Is red meat really that bad for our health? Anna Magee weighs up the scientific evidence.
Few would argue that biting into a juicy sirloin is a pleasure. However, the recent rhetoric that has surrounded meat - especially red meat - has focused on its health dangers rather than its culinary delights.
According to Britain's first vegan shadow agriculture minister, Kerry McCarthy, meat should be treated like tobacco, with some studies claiming eating red meat will fast track you to cancer, heart disease, obesity and an early death.
However, while some are calling for a government campaign to encourage people to stop eating it, other studies say meat provides vital minerals. There is also the fact that the world's oldest living person, Susannah Mushatt Jones, who turned 116 in July, claims to eat bacon every day.
So, what is the truth? We asked leading nutritional experts about what to believe - and do - about meat.
Is it as bad for you as smoking?
"That chicken wing you're eating could be as deadly as a cigarette," screamed the press release from one study, published in March last year in the journal Cell Metabolism. It found people with diets high in animal proteins such as meat and cheese had a similar cancer risk to those that smoked 20 cigarettes a day.
However, Professor Tim Key, a Cancer Research UK scientist from the Cancer Epidemiology Unit at Oxford University, who has been studying the links between cancer and diet on more than 50,000 subjects for the past decade disagrees.
"It's misleading to put meat in the same bracket as smoking; it's highly unlikely the effect from meat is as bad as they say it is."
In fact, the researchers found few links between animal protein consumption and early death until they split the subjects into two groups, one aged between 50 and 65 and the other, over 65.
In the 50-65 age group, those that got a fifth or more of their calories from animal proteins such as red meat had a 74 per cent higher risk of death. But what wasn't widely reported was that in the over-65 group, eating a diet high in protein including red meat had a protective effect.
The researchers hypothesised that protein could control the growth hormone IGF-1, which helps our bodies grow but has been linked to cancer. Levels of IGF-1 dramatically drop off after 65, leading to potential frailty and muscle loss.
"While high-protein intake during middle age is harmful," the authors theorised, "it's protective for older adults: those over 65 who ate a moderate or high-protein diet were less susceptible to disease."
Professor Key says: "It is plausible that higher levels of the IGF-1 hormone might be good for people entering older age and it's an area scientists are currently working on, but it's not yet established to be true."
Will eating meat affect my lifespan?
Several large-scale studies have linked a meat-free diet to longevity. The Blue Zones project, which studies the diets of the world's longest-lived people, such as the Japanese in Okinawa and the Italians in Sardinia, shows that they thrive on plant-based, low or meat-free diets.
However, the European Prospective Investigation into Cancer (EPIC), which has followed more than half a million people in 10 European countries for the past 12 years, has found that small amounts of red meat - less than 80 grams a day - had no effect on mortality.
In fact, Professor Key, who has worked on the British arm of the research, called EPIC Oxford, says this has been reinforced by the latest, as yet unpublished, findings from the study. "We have looked at around 5,000 deaths a month since our last results were published in 2009 and are still not seeing any difference between the lifespans of vegetarians and meat-eaters," he says.
But there are caveats. "The key is in the amount of red meat consumed," says Professor Key. "More than around 70 grams a day was associated with increased risk."
It is fine to save up your weekly portions and have two juicy 250 gram slices of rump.
"As far as we know, that would probably be the same as having a small amount every day," Professor Key says.
Does it increase the risk of heart attack?
"Studies have linked higher intakes of red-meat consumption to higher risk of heart disease," says Victoria Taylor, chief dietitian with the British Heart Foundation (BHF).
In terms of preventing heart attacks, eating less red meat and more specifically a Mediterranean diet may be advisable, says Taylor.
A recent, randomised controlled trial published in The New England Journal of Medicine on nearly 7,500 men and women between the ages of 55 and 80 who were at increased risk of heart disease, found a lower incidence of heart attack in those that ate a Mediterranean-style diet and replaced one portion of red meat a week with white meat, fish, beans or lentils. The lowest risk was found in those that added extra olive oil and nuts to their diets.
Are antibiotics and hormones a problem?
The use of hormones in British meat was outlawed in the Eighties (but they are still used widely in the US). However, the use of antibiotics in British meat has increased by 35 per cent in the past four years. Many believe this over-use is contributing to the problem of human antibiotic resistance - a link recently recognised by the World Health Organisation, says Lee Holdstock of the Soil Association.
Routine antibiotic use is highest in intensively farmed pigs - 200 times that used in sheep - and often used in feed as a preventative measure, says Holdstock. So if you can afford only one organic meat, make it pork. In non-organic farming, wherever antibiotics are used, the treated animals are not allowed to go to slaughter for a set time to ensure there is no residue of the drugs in their bodies, says a spokesman for the Agriculture and Meat Board.
Does eating meat cause cancer?
Last month the World Cancer Research Fun (WCRF) concluded that red meat consumption was strongly linked to the development of colorectal cancer and that by eating no more than 500 grams a week of cooked beef, lamb or pork we could considerably lower our risk of developing the disease.
This could relate to the high saturated fat content in red meat, says Dr Rosalind Miller, nutrition scientist at the British Nutrition Foundation.
"It might also be down to a substance called heme iron found naturally in red meat, high levels of which have been shown to cause the formation of carcinogenic compounds."
There is also evidence that the consumption of processed meats can increase the risk of stomach cancer, says Professor Key.
Will eating meat make me fat?
One study from Tufts University in Massachusetts published in April analysed studied the diets of 120,000 people over 16 years old and found large intakes of red meat were associated with weight gain. But go easy on processed meat replacements, says Rick Miller, of the British Dietetic Association. They are often high in salt.
"The best vegetarian proteins come from tempeh, tofu [which are soya-based] and beans," he says.
Besides, a piece of meat without any fat will contain the same calories as it weighs in grams.