What's on the menu for a sustainable future?

No human activity has a greater impact on the planet than food production and consumption. The expansion of industrial agriculture around the globe means the world is now producing more food than ever, dazzling consumers with unprecedented choice. Some consumers, that is. One billion people live in chronic hunger today, and the supply challenge will only get more difficult with population growth, water stress, biodiversity loss and climate change.

Efficiencies in production and distribution will play their part in cutting waste, but what can be done at the consumer end of the chain? What we choose to eat is not simply a matter of personal taste: our diets have vast implications for the health of the planet. Can we re-imagine our diets so that they entertain our taste buds, satisfy our stomachs and keep us in good health - while also helping to enrich biodiversity, maintain water supplies and decrease greenhouse gas emissions?

It may sound a reasonable political goal, but make it personal and it soon becomes a hot potato. Of course, no one wants their favourite dish struck off the menu. But is it our attitude towards food that needs to change, above all?

"We almost feel we have a right to eat what we like", says Ann-Marie Brouder, who works with organisations across the food system at Forum for the Future. But, Brouder warns, if we don't consider the impacts of our choices now, and adjust them accordingly, it's unlikely we'll enjoy the same plentiful supply and affordable prices in years to come. She believes change is possible: after all, we get used to setting our own dietary limits - "maybe once we're over eight years old!"

David Russell, Founder of the strategic food consultancy The Russell Partnership, would like to see a new culture emerge, in which we think of food as something to share - beyond our own household. "We're very focused on looking after our own needs", he says, "but where is the thought of how the whole world feeds itself?"

Feeding the world on a sustainable diet is the focus of a joint report by the UN Food and Agriculture Organization [FAO] and Bioversity International, published in 2010. It stressed the need to narrow the 'nutrition gap': the difference between the foods we make readily available, and those we actually need for better nutrition.

So what sort of diet are we talking about? Thankfully, austerity on a plate isn't it. Greater diversity is actually the recommendation of the experts. Currently, the three major staple foods (rice, wheat and maize) supply 60 percent of the global calorie intake from plants. It's an alarming over-simplification of diet and agriculture, says Emile Frison, Director General of Bioversity International. In Kenya, Bioversity is working to reintroduce leafy greens to the table and markets, and in India it has partnered the Swaminathan Foundation to reintroduce the ancient grain millet in regions where its production had been abandoned in favour of cassava for starch.

Attitudes do change... Not long ago, oysters were dismissed as the 'pigeons of the sea'

But changing habits isn't easy, admits Frison. "In Kenya, the major obstacle in getting those leafy vegetables onto the table was one of image. [There's a] common conception that this is the food of the poor." Cultural attitudes towards food do change though. Not so long ago, oysters were dismissed as the 'pigeons of the sea': now they're a delicacy to grace trendy wine bars...

The promise of a new foodie culture, with diversity at its heart, is significant. If the 3.5 million people who signed the FAO's petition to ask governments to eliminate hunger were to embark on a year of gastronomic experimentation, the lay of the land in years to come may be very different. So where should they begin?

Meat for a treat

Whether they like it medium or rare, meat is the burning question for many. Is vegetarianism the only way to feed the world?

By no means, says Duncan Williamson, Senior Food Policy Advisor at WWF. "You can eat meat and have a sustainable diet", he maintains. "We just can't eat meat the way we currently are."

Worldwide meat consumption is increasing astronomically. The UN predicts that by 2050 meat production will nearly double to 465 million tonnes annually to keep pace with demand. But livestock rearing already takes up to 30% of all ice-free land on the planet, and is responsible for 18-25 percent of global CO 2 emissions, with its dependence on pesticides, fertilisers, fuel, feed and water. What's more, the growing faith in 'a steak for every plate' is doing no good to global health. For the first time in history, chronic diseases such as diabetes, obesity, heart disease and certain cancers are appearing in significant numbers in Japan, China and parts of Southeast Asia and Africa.

"Meat has gone from being an occasional treat to something people expect at every meal", Williamson explains. "There's this idea that a 'real' meal consists of a big chunk of meat with a small portion of veg on the side. It should be the reverse."

"By necessity, meat can't continue to be the centre of Western diets", agrees Danielle Nierenberg, Director of the Worldwatch Institute's Nourishing the Planet programme. "But people can benefit from the added animal protein of using meat in smaller portions, or as flavouring."

While the livestock industry has a bad rap, meat and dairy production can be part of a thriving ecosystem, helping to renew the fertility of the soil, and making organic farming financially viable. Operations that allow livestock to graze rather than rely on feed grains can have a much lower environmental impact, using less water and fossil fuel and producing less waste. Moreover, raising animals in these more humane settings also translates into healthier meat, with lower levels of fat and more omega-3s.

Although smaller animals, like chicken and turkey, are often cited as smarter choices for the heart and the environment, Williamson notes that impact depends on scale. The 4,325 litres of water used to produce a kilogram of chicken may seem modest compared to 15,415 litres spent to produce the same amount of beef. But the picture changes when considering that chicken consumption has increased more than 400 percent in the EU since the 1960s. According to the Physicians Committee for Responsible Medicine [PCRM], Americans now consume one million chickens each hour. "The point is not to just switch from red meat to white meat because it's healthier, but to eat less altogether", argues Williamson.

For diversity, try wild species, like boar, deer, and rabbit

As with produce, animal diversity also benefits both producers and planet. Williamson suggests trying wild species, like boar, deer and rabbit. Russell says integrating more non-meat proteins is also essential. "You don't need to replace beef, but to supplement it", he says, whether from beans and legumes, or from more 'radical' options, like algae and insects. "The alternatives are clearly there, and they're not second best but part of the right answer for a sustainable future."

Chasing the rainbow

If meat is to be savoured as an occasional side dish, what should our staples be? Marion Nestle is a nutritional scientist at New York University, and author of Why Calories Count: From Science to Politics. For her, tomorrow's top meal should feature "more vegetables and smaller portions of everything else". Not only does a plant-based diet offer more nutrients, she says, but it has less ecological impact than a carnivorous one. Susan Levin, Director of nutrition education at the PCRM, agrees. A diet composed of fruits, grains and vegetables could satisfy the entirety of human nutritional requirements, she says, including protein.

But the same helping of greens every day won't do the trick. Despite the abundance of the world's edible plants, just 12 species make up 75 percent of the plant life consumed. Increasingly, fruits and vegetables are cultivated as monocrops.

The result is that roughly 70 percent of agricultural genetic diversity has been lost since 1990. Experts are calling for a shift towards diverse species, prudent irrigation and fewer chemicals. Research from FAO, the World Bank, the US Agency for International Development and the Consultative Group on International Agricultural Research all indicate that this will bolster food security, improve nutrition and preserve resources. Fortunately, nutritional research is also calling for more variety on the plate. Rather than focusing on 'superfoods' (like pomegranates, acai or wheatgrass), diets should contain 20-30 biologically distinct foods each week. Nierenberg would also like to see more indigenous and wild plants on the menu, and in particular native species. She notes that native species are nutrient-rich, and tend to be better adapted to local environmental conditions, and as a result require less irrigation, pesticides and fertilisers.

A variety of colours will take care of everything you need

"Go for a rainbow" is Levin's advice. "Eating a variety of colors will take care of everything you need."

Urban farming can play its part too. Take Montreal's Lufa Farms: a 31,000 square foot greenhouse on top of an office building, complete with a rainwater harvesting and recycling system. It's supplying fresh, seasonal veg to residents via a box scheme and pick-up points, and offering advice on "what to do with that mysterious spicy leafy green".

- Green Futures