KEY POINTS:
In this life there is no shortage of dietary advice. So it might seem unhelpful to fling in yet another dietary definition, but ecotarianism has a winningly common-sense approach.
The concept is simple - eat the foods with the lowest environmental burden, those with the lowest global-warming potential and the least chance of messing up the planet with their acidification and pollution potential.
In practice, divining the environmental burden of a tomato in the supermarket is difficult.
Fortunately there are now swathes of academic papers on the lightest (in green terms) foods. Take as your bible Cooking Up A Storm, by Tara Garnett of the University of Surrey in England.
But what does an enviromentalist's ideal diet look like? Strangely it does not necessarily mean eating food dug up in the next-door field, as the idea of food miles (very Nineties) has been displaced by emphasis on the efficiencies of production.
A 2004 German study compared fruit juice from Brazil with local European versions and found that the smaller European producers used more energy to produce and distribute their products.
Nor is an ecotarian necessarily a vegetarian but rather a very discerning meat eater. For example, pig and poultry meat has been shown to have a lower effect on the environment than meat from ruminants, particularly cows.
A Swedish study of the ideal environmental diet suggested we curb our collective sweet tooth and cut our intake of sweets by 50 per cent. And as it appears to be the milk in milk chocolate that produces the greatest burden, a good ecotarian eats dark chocolate.
But the problem with the lifecycle approach is it throws up results that are far from ethically holistic. Take poultry and eggs. The pure lifecycle analysis that rewards high-efficiency feed conversion means non-organic appears to have the lesser eco burden; it doesn't take into account the barbarism of battery hen production.
But as a rule of thumb, organic non-animal products are best, as the organic system uses legumes to fix nitrogen rather than wasting fuel on synthetic fertilisers. The ecotarian keeps frozen products to a minimum and shuns chilled foods; half of all supermarket trucks are now temperature-controlled, creating a huge greenhouse-gas burden.
The exception is frozen peas - a UK study, whimsically titled Give Peas a Chance, demonstrated they were very efficiently produced.
Unlike other dietary factions, ecotarianism has room for fluidity. Take one of today's eco foodstuff villains, the out-of-season tomato which requires a lot of energy to produce. Experts predict that increased use of combined heat and power in horticulture will change this. Lo, the tomato becomes the new mung bean.
- OBSERVER