Shortly before the Copenhagen climate talks last year, the media whipped itself into a frenzy over some "controversial claims" made by Lord Nicholas Stern, author of a government review on the economics of climate change. "Climate chief Lord Stern: Give up meat to save the planet," one headline reported him as saying. Except that he didn't.

When he stated an unpalatable but irrefutable fact – that rearing meat has a higher environmental impact than producing a vegetarian diet – Lord Stern committed an incitement to vegetarianism that many found hard to stomach.

In January 2009 a plan to reduce the amount of meat served in hospitals to healthier and more sustainable levels was included in an NHS carbon reduction strategy. The proposal focused on reducing meat, not cutting it out entirely, and sourcing local produce, but was reported as a "removal" and a "ban" on meat and was criticised in the media. The plan was subsequently scrapped.

Such is our approach to eating – and talking about – meat. While both the health and environmental arguments for a re-think are sound and compelling, it's an issue so sensitive and polarising that the idea of change and moderation simply doesn't cut the mustard.

But the arguments are staggering. Producing meat takes up 70% of the world's farming land and generates a fifth of all greenhouse gas emissions. It requires around three-and-a-half times as much land to produce a high-meat as a low-meat diet. Given that we're on course to double meat production by 2050, surely something has to give?

The health imperatives are as compelling as the environmental concerns. In the west we eat far more meat than is necessary or healthy. New research for Friends of the Earth published today shows that a shift to lower meat diets could prevent 45,000 deaths – and save the NHS £1.2bn – each year. So what's stopping us from cutting down?

For a start, we're not geared up for it. While people who eat no meat at all are identified and identifiable as vegetarians, there is no commonly accepted term for people who eat it only a couple of times a week and are selective about its quality. Attempts to establish a suitable label for the low-meat eater – "ecotarian" and "meat reducer", amazingly, the least awful – haven't caught on.

Our all-or-nothing approach to meat eating leaves us with no understanding – and little tolerance – of the concept of a low-meat meat diet. It's awkward telling friends who know you eat meat that you'd rather have a specially prepared vegetarian option when you're invited round for dinner. It smacks of the sort of hypocritical vegetarianism that people love to sniff out and ridicule and it's much easier to just avoid the issue and eat whatever's going.

But avoiding social and political awkwardness is preventing us – as a society – from transforming our farming sector into one that's sustainable. Producing meat that's planet-friendly and continuing to enjoy it in the future means re-thinking the type and quantity we consume now. While we're distracted by an unhelpful, polarised debate, we're losing out on opportunities to drive forward changes that would help us to make this shift.

Next month MPs have a real opportunity to make a real difference when Rob Flello MP's sustainable livestock bill is voted on in Parliament.

It calls for big changes to the way that the meat and dairy industry is funded and supported and would help ensure that the food we eat is healthier for people and healthier for the planet. Surely that's not so hard to swallow?

• Andy Atkins is the executive director of Friends of the Earth