To be honest, I'm not sure I feel qualified to talk about sustainability in the restaurant industry," James Lowe says with a sigh. "I just don't think that we're really doing enough."

My heart sinks a little: I appreciate his honesty, but I'm at his restaurant Lyle's, in the lull between lunch and dinner, to talk to him about this very subject. It's something Lowe's renowned for: a short, ever-changing menu that responds to what his suppliers have rather than what he wants, and makes the most out of every single last odd and end. Forget nose to tail – or, if you must use that phrase here, bear in mind that it really does mean 'order a pig, break down a carcass and don't order another pig until you have roasted, broiled, baked, cured and otherwise used each bit of it.' It means trout heads, brussels tops and ox hearts – and a proprietor so concerned about his environmental impact that he feels phrases like nose to tail and field to fork are now redundant: too trite to cover the complexity of the issues, and too used (and abused) by marketing teams to be meaningful.

James Lowe at Lyle's in Shoreditch

James Lowe at Lyle's in Shoreditch

Which is why he struggles with the word 'sustainable', and the idea that Lyle's could ever be the model of sustainability I and so many others understand it to be. "Every restaurant opening now seems to claim to be a sustainable operation – and, you know, I'm not sure restaurants really can be," Lowe says. "They create a lot of waste. They rely on polluting methods of transportation." Even Lyle's, which does its level best to source from suppliers who deliver by bike or electric vehicles, uses vans which drive to London once a week from Herefordshire and beyond.

"There is so much conflicting information out there – about food miles, about carbon neutral, about plastic – and I just don't think we know enough about what processes harm and what processes are harmless." Show him a restaurant that claims to be totally sustainable, he continues, and he'll suggest to you that they "are either lying, or they don't understand the depth of the subject."

It all sounds – well, kind of hopeless. Lowe studied environmental science at university, and understands too well the scale and complexity of the challenges that we are facing. "I've been involved in this stuff since back in the day, when it was about sewage on the beach and not dropping litter. I took part in grassroots campaigns as an environmentalist. And what I learnt at university is that just because a paper is published doesn't mean it is necessarily right."

He cites an exposé he read recently about the post-Blue-Planet trend of paper straws: "They take more fossil fuels to make than plastics do, apparently. Of course, you can't just say 'I'm not going to do anything'," he adds quickly. "But you can appreciate that these solutions don't always cover all the angles. We need more research into these issues, and it needs to be transparently government funded – because any research into the environment is inevitably going to be biased according to where the money to fund it has come from."

An artful dish from Lyle's

An artful dish from Lyle's

Lowe is not a conspiracy theorist. He is no cynic, either. He's "a sceptic – and you bloody should be, too, as any good sceptic will tell you," he says, grinning. For his own part, he does what he feels is right on the basis of what he does know – offal is edible, so cook it; air pollution in London is terrible so use bicycles where possible – and what he doesn't know, he does his level best to find out.

This isn't easy: "I just wish there was a way to learn, specifically for restaurants to learn, what practical steps we can take," he says, citing the incredibly effective, government-funded, agency-managed Ugly Fruit campaign in France a few years previously. "With adequate funding and clear guidelines things will happen much faster." Sure, the paper straws may not have been foolproof, but "when it came to plastic packaging, people thought 'I can do that,' and they jumped onto the idea with enthusiasm," he says energetically. "People are acting on it, but if the restaurants are to go much further, we need financial incentive. We're competing with tons of restaurants, sustainable measures are more expensive, and ultimately people do choose where to eat based on money."

Today, Lyle's is one of a growing number of restaurants to have told its suppliers that it doesn't want single-use plastic or wooden packaging. "We want everything to arrive in veg crates that we can unload and send back. It works because we don't have to spend our time breaking down boxes – and because the message goes up the chain that says we're not going to accept it anymore," he says simply. "If I stop accepting the packaging, the veg company has to deal with it. It becomes their headache, so they ask their suppliers to stop using it. I think people have to highlight the individual headaches and come up with a solution – and the good solutions, the common-sense solutions, are usually the most sustainable."

the good solutions, the common-sense solutions, are usually the most sustainable

It's common sense for vegetable companies to reuse the crates they deliver in. It's common sense for Lowe not to throw edible food away. It's common sense for him to source fish from small-scale fishermen who, "because it is their livelihood, are concerned about the amount of fish they catch, and only catch what they feel is a sustainable amount each year." Yes, global cod stocks are running perilously low, calling en masse supplies from the North Sea into question, "but if we are buying from five boats which operate out in the Helford Estuary, and only land 80 kilos of fish a day, and send their fish in reusable deep crates rather than those awful disposable polystyrene boxes…" he shrugs. "To my mind that is a sustainable relationship. It's a closed loop."

Lowe doesn't do concepts. His menu doesn't have a story. When his former PR company asked him for the restaurant's USP when they opened, he didn't really know what to say. "I said I wanted to open a nice restaurant, serving good food. They said that just wasn't interesting enough – and in the end, I decided to part ways because it didn't feel relevant to me." He does have a philosophy – but it's "not a very a rock and roll or foodie-sounding term. Our ethos in the kitchen is just to be pretty common-sense.

"Common sense encompasses nose to tail, and farm to fork, and all that," he continues. "Though I hate those phrases because no one knows what they mean any more." Lowe does, of course – you don't serve as head chef at St. John Bread and Wine for five years without knowing your tripe from your trotters – but that was before venture capitalists jumped on the meat-wagon, and started putting pig's head terrine or crispy pig tails on menus every single day under the banner of 'nose to tail eating'. "You ask, how many pig's heads are you getting though a week? And they say, oh, 120 or so – and I think, where do those pigs come from? What good, ethical farmer is producing 120 pigs heads a week? Where is the rest of it going?" At Lyle's you'll find pig's head terrine on the menu every fortnight, and it lasts for two days because "that is how long two pig's heads will last for – and the pig's heads are attached to the two pigs that we buy every two weeks."

At Lyle's, the first and most fundamental question is where the ingredients come from and who has produced them. They won't bore you with the details – "I hate it in fancy restaurants when they put the dish down and spend five minutes telling you about it. I feel like they do that to make the food better rather than make better food," says Lowe – but if you ask them, they'll happily tell you about the five-year-old Hereford cattle from Tom's farm on the Welsh border which has been hung for three months and slow cooked before making it onto your plate. His vegetables come from a cooperative of farmers in South East London who try and sell everything they produce and transport their produce by bike to their buyers via a woman named Chrissie. "They'll ring and say, we've got five kilos of this – and we'll take it, because it will be the best produce of the moment. We're considerate about what we ask of them – and they don't put too much strain on the land as a result."

In the end, what sustainability invariably boils down to is greed, and the surfeit of it in today's culture. "Greed is the big thing that makes things unsustainable – because you are pushing systems that can't handle that pressure." You're straining the land, or depleting fish stocks, or farming cattle and chickens on an industrial scale. It's one of the reasons Lowe hasn't "cranked the numbers" at Lyle's and now, after four years, is only just finishing paying its lenders. "From an investment perspective that's terrible," he laughs – "but I like cooking and I like supporting our suppliers. I like employing these people" – he gestures around the warm, bubbling open kitchen – "and for that to continue, I need to pay them properly." In an industry where staff retention is pitifully low, chefs staying two or three years, as is the case with Lowe's head and sous chefs, is remarkable: proof, were it needed, that "if you pay people properly, and look after their working hours, and ensure they are growing on learning, they will stay."

The dining room at Lyle's in Shoreditch

Staff retention breeds familiarity; familiarity breeds teamwork; and teamwork breeds the sort of peer pressure required for high-quality, ethical working practices. "If you employ the right people and create the right working environment, you shouldn't need to be standing over them watching what they throw away. They will feel that philosophy themselves." It's why he's such a fan of open kitchens. "For my part, I think one of the reasons you see high instances of bullying and sexism in restaurants is that they feel separate to the outside world. With an open kitchen, you don't have eight men in a boiler room screaming at each other." Of course Lyle's gets busy, and the kitchen hot, but there's a sense of respect and creativity which is scarce in fine dining kitchens where 'put up and shut up' is the prevailing, military attitude. "Our chefs care about what they are doing, and genuinely get a kick out of doing something with an ingredient that would otherwise have gone in the bin."

Is it more expensive to make an effort to be sustainable? "Yes," Lowe says, "but it makes me feel better. I am not cutting corners. If I was, I would feel the same way as I would if the food wasn't cooked right." Besides, he continues, "being sustainable also means more work for me, which I really enjoy." It means speaking to current suppliers about what they have; reaching out to new suppliers "because Chrissie doesn't have enough beets so recommends you speak to Harry at OrganicLea, who grows amazing beets"; and finding ingredients you had never even considered before "because Harry says 'Have you ever tried potato leaves?' And it turns out that's a thing, and all of a sudden we are helping them generate money from what was previously a waste product."

City restaurants are not a good thing for the environment. But it's all I know how to do

Lowe's criteria for new suppliers is simple. "I talk to them a lot, and think – do I like the sound of working with you? Do you have enthusiasm about working with us? Are you on my wavelength? And – crucially – is the product really, really good?" He would love to own a restaurant with its own allotment and smallholding. His hero, so far as sustainability is concerned, is Matt Orlando of Amass on the outskirts of Copenhagen. "Matt is absolutely hands down more knowledgeable about the systems that get produce to a restaurant than anyone I know. His recycling and zero waste approach is better than anyone's. You should speak to him," he enthuses – and I would absolutely love to, having eaten there. But this is East London, and the allotment and kitchen garden that define Amass could hardly be accommodated within the crowded, car fume-choked 100 square metres that is Lyle's, Boxpark and Bethnal Green Road.

"City restaurants are not a good thing for the environment. There's no denying that. But it's all I know how to do, and I can't give it up," he shrugs helplessly. What he can and does do, however, is his level best to make Lyle's adopt the most sustainable methods he knows. Next year he'll open his second restaurant – location TBC, and for goodness' sake don't ask him about the concept – but he's already thinking about the various ways he can shore up its sustainability credentials: by divvying up ingredients between the two places, like at Relæ and Manfreds in Copenhagen ("the head chef Christian Puglisi has this cauliflower dish at Relæ which only use the florets of a cauliflower, so he sends the rest to Manfreds to use in a cauliflower soup on their menu. It's great," he says) to sharing deliveries with local restaurants so you can have one or two vans making one journey each morning.

Lowe might not feel qualified to talk about sustainability in the restaurant industry, but he's doing his level best by his restaurant, and that is a hell of a lot more than most chefs in this country. We could do worse than to take heed.

lyleslondon.com