It’s not called “a meaty issue” for nothing. New research shows that a meat eating diet has about double the greenhouse gas emissions of a vegan diet and about 50 per cent more greenhouse gas emissions than a vegetarian diet. The Naked Scientists website recently ran an interview with Dr Peter Scarborough from the University of Oxford about their work with sustainable diets.

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According to Dr Scarborough, a healthy sustainable diet largely “boils down to one area and that is meat consumption”.

“A diet that is lower in meat, and higher in plant-based foods, is “probably hitting something which is both healthier and better for the environment” he says. 

“In terms of sustainability, we’ve known for a long time that greenhouse gas emissions related with plant based foods compared to meat based foods are far, far lower - orders of magnitude lower. That’s particularly the case for ruminant meats, so that’s for cows and for sheep.

“When you’re talking about animal based products you’ve got inefficiencies in the system of raising livestock, which is about the fact that you have to feed animals with food that otherwise could have gone to human consumption.

“Then you’ve also got natural systems with ruminants like methane production when cows burp and they fart. Essentially methane is about 25% times as high a greenhouse gas emission as carbon. So they all add up to a much higher greenhouse gas emissions for meat based foods than plant based foods.”

Another interesting statistic: In total, 30% of the world’s greenhouse gas emissions that are produced are from global food systems.

“The important thing is it isn’t just about changing from being a meat eater to being a vegan, that’s a big switch, it’s a big lifestyle change that not many people would be willing to make,’ says Dr Scarborough. “But we know that dietary greenhouse gas emissions are very well correlated with the amount of meat that you eat. So if you just reduce the amount of meat that you consume; start cutting it back on a few days a week, you’ll make a big impact on your dietary carbon footprint.”

Food sustainability issues are particularly important with the developing world getting richer and moving towards more western diets – “and that’s a higher greenhouse gas emission footprint there”.

Diet and health research

In terms of health comparisons the research is informative: “We know from the Cohort studies, which are studies which look at people with different diet groups and follow them up over a long time and see how there’s differences in health outcomes… that there’s lower cardiovascular disease outcomes related with a lower meat diet,” says Dr Scarborough.

“We also know there’s now very good evidence that a lower meat diet, particularly red and processed meat diet, is related with lower colorectal cancer outcomes. We also know from randomised control trials of short term changes in meat consumption, so moving to small lower meat diets, that’s also associated with reduction in body weight, and reductions in blood cholesterol levels.”

Fishy about fish

Dr Scarborough says that the common belief that we can eat fish without a care in the world is inaccurate. He talks about the situation in Britain but it applies to many countries: “There are some tensions. The classic one is fish, so the healthy advice for healthy eating is for everyone to eat two portions of fish a week, one of which is oily fish. If everyone in Britain actually met those guidelines, there’d probably be no fish left in the sea; that clearly works against sustainability.”

Information above sourced from Dr Scarborough’s interview with Georgia Mills:

What is 'The Naked Scientists' ?

Based at Cambridge University's Institute of Continuing Education (ICE), the Naked Scientists are a team of scientists, doctors and communicators whose passion is to help the general public to understand and engage with the worlds of science, technology and medicine. Created and launched in 2001 by Chris Smith, the Naked Scientists was one of the first podcasts to exist and is now one of the world's most popular science shows, achieving over 50 million programme downloads in the last 5 years.