According to a team from Cornell University, the US food production and supply systems use an estimated 19 per cent of the total energy used in the nation, most of which comes from non-renewable sources that are in short supply like petroleum and natural gas.
David Pimentel and colleagues say it is of paramount importance that ways are found to reduce this significant fuel consumption; as resources run out – both sourced domestically and expensive imports – the US will have to rely on coal and other renewable energy sources.
But coal supplies are expected to last only 50 to 100 years, and the population is expected to rise from 317m to one billion in the next 100 years. “It is unlikely that such a population cold be sustained with the diminishing availability of fossil fuels,” wrote Pimentel in a new report published in Human Ecology.
The first suggestion Pimentel gives to ease the situation puts the onus on consumers – to actually eat less food. At present average energy consumption by US consumers is 3747 calories per day – between 1200 and 1500 more than are actually recommended.
“Reducing the calorie intake to a lower level would significantly reduce the energy used in food products,” wrote Pimentel.
Encouraging people to eat less, so that they produce and ship less, would no doubt be an unpopular suggestion to put on food manufacturers, since it would have a very clear impact on their sales.
The US packaged food market saw retail sales of some $317bn in 2007, according to Euromonitor International.
However the researchers point out that reducing energy usage can actually come about by changing food choices.
The American diet is heavily weighted towards meat and other animal products and processed foods. But a vegetarian diet containing 3747 kcal per day would require 33 per cent less fossil energy than the current average American diet, Pimentel has calculated.
So, replacing junk food for potatoes, rice, fruit and vegetable would make a significant contribution to the energy story. It would also help improve the health of the nation, and surely trim waist-lines across the country, where more than 30 per cent of the population is now estimated to be obese.
Food production
Whilst the consumer is put under the spotlight as having the greatest power to ease the energy problem, food production methods are also scrutinised.
Shifting towards traditional, organic farming methods would help, the report says, because conventional meat and dairy production is very energy intensive. Similarly for crops reduced pesticide use, and more use of manure, cover crops and crop rotations could improve energy efficiency.
According to USDA figures from 2004, one billion pounds of pesticides are used in US agriculture per year. None are used in organic farming.
Herbicidal weed control at a level of 6.2 kg of herbicide per hectare plus sprayer application is said to require about 720000 kcal of energy per hectare – twice that needed for mechanical weed control.
Processing and supply systems
At the food production and processing levels, the industry should be paying attention to energy-saving considerations, such as production efficiencies, heating and lighting economies, and more environmental packaging solutions.
On average, food in the US travels 2400 km (1491 miles) before it is consumed by an American, requiring two million kcal – 1.4 times the energy the consumer actually receives when they eat it.
“A simple but radical reduction in transport distance would lead to great savings in energy,” says Pimentel.
While it may seem like the food industry is the driving force behind these measures, in fact the report authors say again that consumers have their part to play.
If consumers source food locally, there will be less demand for food flown or driven in from elsewhere; if they eat less processed foods, there will be less demand for the industry to make products in this way – and, in theory at least, food processing will be reduced.