A Sustainable Diet

World hunger remains a serious problem. According to the UN Food and Agriculture Organisation (FAO), 800 million people worldwide are undernourished. With the current world population of six billion (6 thousand million) forecast to increase to 7.5 billion by 2020 and to about 9 billion by 2050 it is clear that food production will need to increase substantially over the next 50 years just to keep pace with population increase. Based on past trends, 1 billion hectares of natural ecosystems (an area greater than that of the United States) will need to be converted to agriculture to cope with the extra demand, coupled with 250% increases in fertilizer and pesticide use [1]. At the other end of the dietary scale, it has been estimated that 1.2 billion people worldwide are overfed. One in four US citizens and one in five Britons are clinically obese.  Clearly, some are eating more than their fair share of the cake!

The high consumption of meat and other animal products in developed countries places a massive burden on the world’s agricultural land. Dutch ecologist Lucas Reijnders has estimated that meat protein production requires 6-17 times more land, 4-26 times as much water, and up to 50 times as much fossil fuel as the equivalent amount of vegetable protein. Emissions of the greenhouse gas carbon dioxide, biocides and compounds that cause acid rain are all at least 6 times greater for meat production compared with soybean production [2]. Worldwide, more than half the land which could be used for growing plants for direct human consumption is used to produce animal feed.  This land could support 5-10 times as many people on a vegetarian diet. Fish farming compares equally badly.  For example, farmed salmon are fed 3-5 times their weight in wild fish caught from oceans that that are already severely depleted.

With these facts in mind, the Council of the International Vegetarian Union issued the following statement at the 35th World Vegetarian Congress held in Edinburgh in July 2002:

The International Vegetarian Union (IVU), which comprises over 100 vegetarian societies around the world, at its 35th World Vegetarian Congress with 300 participants, calls on the WSSD (World Summit on Sustainable Development) meeting in Johannesburg in August, to take active steps to reduce meat consumption globally. This action is needed in order to reduce the adverse effect of factory farming and meat production on the environment, on human nutrition and health and on animal welfare. The world's population can then live more healthily on a plant-based diet, scarce global food resources can be fed directly to humans, rather than wastefully to farm animals and water, land and air quality would also be enhanced.

Support for the vegetarian position comes from Compassion in World Farming, who sent representatives to the World Summit on Sustainable Development and the FAO World Food Summit held in June. In a recent report they call on policymakers “to lead a move away from industrial animal agriculture and to give positive support to more humane and sustainable forms of food production that are quality, rather than quantity, driven”. At the same time, “affluent populations must be guided to eat fewer animal products” [3].

So what constitutes a ‘sustainable diet’, and would such a diet be vegetarian? Nutritionist Joan Dye Gussow defines a ‘sustainable agriculture’ as “one that uses human and natural resources to produce food and fibre in a manner … that is not wasteful of such finite resources as top soil, water and fossil energy”. Diets arising from such a system would clearly emphasize plant foods in preference to animal foods, but Gussow concludes that “the presence of both plants and animals in sustainable natural systems argues not for vegetarianism but for a much lower intake of animal products and a return to integrated systems of plant and animal production” [4]. Reijnders also concedes that “much agricultural land is unsuitable for cropping, but is fit for sustaining livestock”, and the CIWF Trust report highlights the importance of domestic animals in maintaining soil fertility and providing draught power in developing countries. Thus, a sustainable diet might not be completely vegetarian, but vegetarian diets which emphasize organic, locally-produced foods are highly sustainable and should be the diet of choice for environmentalists.

Paul Appleby, September 2002

References:

  1. David Tilman et al. Forecasting agriculturally driven global environmental change. Science, 13/4/2001.
  2. Lucas Reijnders. Environmental impacts of meat production and vegetarianism. In: Vegetarian Nutrition, CRC Press, 2001.
  3. Leah Garcés. The detrimental impacts of industrial animal agriculture. Compassion in World Farming Trust, 2002.
  4. Joan Dye Gussow. Mediterranean diets: are they environmentally responsible? Am J Clin Nutr 1995; 61: 1383S-9S.

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This page created 22 September 2002 by Paul Appleby.