The thorny (or should that be bony?) subject of what we eat

I was recently told by a colleague that, "we were born to eat flesh". As a biologist, I would beg to differ.  Our dentition, evolved from an omnivorous diet, combines cutting and grinding actions.  While our canines and incisors can tear into meat, our molars enable us to chew fibrous plant material in much the same way that ruminants do.  We are well adapted to a diet of fruit, vegetables and grains - supplemented with meat when we can get it.  Our short alimentary canal indicates that, rather than being born to eat meat, we were born to cook.  The combination of farming and fire provides plentiful calories in our diet that are much more readily absorbed than the resistant flesh of raw animal and plant tissues.  Steve Jones, Professor of Genetics at University College, London, observes wryly that anyone trying to live exclusively on raw food would die of malnutrition within 90 days.

This led onto the subject of fish because my colleague felt "more strongly about the waste involved with eating fish than with cows, sheep, pigs, chicken, etc."  On the day of this exchange, I happened to be cooking sea bream for dinner.  Whenever we buy whole fish, I boil up the leftovers with a few vegetables and a drop of lemon juice or vinegar to produce a richly-flavoured broth.  Left to chill, the broth sets to a loose jelly which forms the base for another delicious meal, such as risotto or paella.  The only waste is the guts and a handful of sharp fishbones that can be composted.

Of course, there can be waste a-plenty in the supply chain.  Hugh Fearnley-Whittingstall's "Fish Fight" campaign has raised our awareness of the appalling practice known as discards, where perfectly edible, dead fish are thrown back into the sea because the vessel has exceeded its fishing quotas.  At the same time, Greenpeace campaigned against the use of purse-seine nets and Fish Aggregating Devices (FADs) to fish for tuna, as these methods result in carnage for other species including shark, dolphins and endangered sea turtles.  This incredible campaign resulted in the immediate end to these fishing practices by all the major producers and retailers of tinned tuna.

No such consumer revolution has yet been sparked against the rape of tropical peatland rainforests in Indonesia and Malaysia, which are home to all three species of orangutan, in pursuit of the latest gold rush.  Palm oil is present in about a quarter of all grocery products.  It is widely used in toiletries and cosmetics.  Most insidious is its inclusion, by law, as biodiesel in our transport fuel, under the Renewable Transport Fuel Obligation (RTFO). Liquid biofuels, including palm oil, produced from clearing virgin rainforest have a carbon intensity that is many times that of the fossil fuels they are intended to replace.  Yet that is not stopping Eric Pickles and his Department for Communities and Local Government from granting planning consent for palm-oil fired power stations in Britain, under the deceptive claim that biofuels are a central component of Britain's plans to decarbonise our energy infrastructure in the coming decades.

Industry moves to secure sustainable supplies of palm oil, through the Round Table on Sustainable Palm Oil (RSPO) are a figleaf, however well intentioned, that is allowing the continued destruction of remaining orang-utan habitat.  Most of the major retailers and brands supplying our consumer goods have pledged to use only sustainably-sourced palm oil by 2015.  In the meantime, deliveries of RSPO-certified sustainable palm oil to the UK remain unsold because so few of the major players are yet prepared to take the competitive hit of paying more for this ethical ingredient while they can still get the cheap oil, whose by-product is deforestation, leading directly to gargantuan greenhouse gas emissions, biodiversity loss and the deaths of our few remaining cousins, whose name comes from the Malay language and means "people of the forest".

So what are the most sustainable and ethical foods in our diets? Allotment-holders, by their toil, earn the right to eat fresh, healthy, seasonal vegetables with no food miles whatsoever.  Those of us with less time, talent and tenacity continue to depend on the supermarket for our weekly shop.  The best we can do there, I believe, is to buy locally-grown food that is in season, avoiding the need for fossil fuels to heat greenhouses and to fly ripe produce to our tables from around the world.   Meat and dairy products are among the most carbon-intensive foods we can buy and so it makes sense to eat less of these foods.

Instead, consider the point made by Colin Tudge in his excellent study of the history and future of food production, "So Shall we Reap" (2002).   Traditional combinations of staple foods (carbohydrate-rich grains and roots) with vegetables or pulses have developed as regional cuisines around the world.  The blend of proteins in each of these combinations provide all the essential amino acids we need to remain healthy.  Tudge's examples include rice and tofu (bean curd) in the Far East, rice and peas in the West Indies, tortillas (maize) and frijoles (beans) in Mexico - and even baked beans on toast (wheat)!  We have all experienced other, traditional combinations of carbohydrate and vegetables, from pasta and beans to potatoes and peas.

The message to take away is that meat and dairy products are not the core of a sustainable, ethical and healthy diet.  That role is reserved for the rainbow varieties of peas, beans, pulses and vegetables which we can combine with our staple foods, transforming them from monotonous carbs into delicious, nutritious and aesthetic cuisine.  And if there WAS a take-away serving that, I'd be the first to order a home delivery from their carbon-neutral rickshaw service!