VEGETARIANS may be healthier, but meat eaters do more for the environment. A
survey of the energy used to produce and distribute various foods has found that
meat and processed food such as sweets, ice cream, potato chips and white bread
are among the most energy-efficient鈥攁nd so least polluting鈥攆oods in
our diet. Tea, coffee, tomatoes, salad vegetables and white fish, on the other
hand, are distinctly environmentally unfriendly.
David Coley and colleagues of the Centre for Energy and the Environment at
the University of Exeter have analysed how much energy from fuel is used in the
complete production cycle of food in a typical shopping basket. The analysis
includes the manufacture and application of fertilisers and other chemicals,
harvesting, processing, packaging, transport and waste disposal. Geographical
differences have been averaged out.
In a study of the diets of more than 2000 people, they found that it takes
around 18 000 mega-joules of energy each year to get a typical Briton鈥檚 food
to the table. This is almost six times the energy contained in the food itself.
In all, the process consumes almost a tenth of the national energy budget,
adding 15 million tonnes of carbon to the atmosphere in the form of carbon
dioxide.
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But people鈥檚 diets vary hugely. The study suggests that a sixth of Britons
consume food over a year that requires less than 10 000 MJ to produce, while the
annual diets of another sixth require more than 25 000 MJ.
The study will trouble those trying to be both healthy and green. The most
energy-intensive item is coffee, which requires 177 MJ of energy to produce 1 MJ
of food intake. But typical salad vegetables require 45 MJ and white fish 36,
compared to 8 MJ for beef and burgers, 7 for chicken and 6 for lamb.
Worse still for the environmental consciences of healthy eaters, while fresh
fruit consumes between 10 and 22 MJ, sugary confectionery, crisps, white bread
and ice cream are all right at the bottom of the table, consuming less than 1 MJ
each.
鈥淢eat does well because it is not highly processed, provides a lot of
calories and is often grown locally,鈥� says Coley. 鈥淏ut obviously it makes a lot
of difference whether the meat comes from the local farm or Brazil. I live close
to Dartmoor, where local cabbages and lamb would produce a very different score
from New Zealand lamb and Kenyan green beans.鈥�
In a sense, says Coley, we all 鈥渆at oil鈥�. The modern food industry is 鈥渋n
many ways a means of converting fossil fuels into edible forms. Food is a large
part of an individual鈥檚 impact on the greenhouse effect. Many of us could change
our diets to have a lot less impact.鈥�
