Sunday, February 4, 2007

Dietary patterns and environmental impact

It has often been discussed if changes in food consumption can help world sustainability. One Italian-based study compared the usual Italian diet, balanced omnivorous diets (organic and conventional) and balanced vegetarian/vegan diets (organic and conventional). The diets are accessed according to their damage to human health, ecosystems and resources using three perspectives: short-term, medium-term, and long-term adverse effects.

It was found that the normal unbalanced Italian diet had the greatest impact on the environment. Consumption of animal products within the same way of food production (either organic or conventional) also had a greater impact on the environment.

Analysis of a single type of food shows that Beef has the greatest impact on the environment, followed by fish, cheese and milk.

The different impacts of an omnivorous diet on the environment are recorded as follows:
3 to 4% of the impact on environment is due to eutrophication. Farm animals produce 19m tons of waste each year in Italy alone. The waste cannot be used as fertilizers due to their content. They enter water bodies and pollute them.

5 to 13% of the impact is due to land usage. Europe can produce enough vegetable proteins to feed its inhabitants, but not its livestock. 80% of vegetable proteins fed to European livestock come from other countries (including developing ones) and depletes their environmental resources. Growing of livestock feed meant for richer countries also aggravates desertification in Africa. Presently, 25% of the total land area in the world is undergoing desertification. The increase requirement for land use for animal husbandry is associated with deforestation. Most of the forest cleared from the Amazon (88%) is used for cattle grazing.

5 to 18% is of the impact is due to damage to respiration from inorganic compounds and 20 to 26% from fossil fuel consumption. When plants are fed to animals, much of the protein and energy content of the plants are wasted as animals make use of them for metabolism and build animal parts that are non-edible. It would thus be more efficient to consume plants directly. Animal husbandry also wastes a tremendous amount of fuel. One calorie of beef requires 40 calories of fuel and milk needs 14 calories. Grains, however, requires only 2.2 calories.

The greatest percentage of the total impact (41 to 46%) comes from water consumption. 70% of freshwater is used for agriculture and animal farming. A shift towards a more plant-based diet would help the present situation. This is because many plants, such as grains from agriculture are used as feed for grain-fed cattle. Even grazing cattle consume more water than that required for growing cereals. Water has to be used for cleaning livestock facilities as well.

Moreover, malnutrition and hunger have been linked to declining land, water, and energy resources per person. Hence, vegetarian and vegan diets help preserve environmental resources and reduce hunger and malnutrition problems in poorer nations.

Study source reference:
L Baroni, L Cenci, M Tettamanti and M Berati "Evaluating the environmental impact of various dietary patterns combined with different food production systems" European Journal of Clinical Nutrition (2006), 1–8

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