Food Matters: Reducing our environmental impact through the food we eat

A regular column, produced by the National Office Public Interest team, which investigates how psychology can contribute to addressing the growing environmental crisis facing our world.

Public concern for the environment is higher than ever, with people everywhere working to conserve resources and reduce travel.  But what about food? We don’t hear much about the environmental costs of the modern food industry, which contributes a third of global greenhouse gas emissions. Surprising? How many of us realize that food choices are among the easiest ways to reduce our carbon imprint - where we buy food, what we buy, and how we cook it?

The food industry is a prolific consumer of fossil fuels and producer of poisonous wastes at all levels of food production, from growing, processing and manufacturing, to packaging, distribution, transportation, storage, preparation and disposal. In the US, one person consumes 400 gallons of oil a year in food. (Food facts sourced from Underwood et al., 2006, unless otherwise referenced).  

Over the last century, the food system changed from a food supply chain, controlled by suppliers (e.g. farmers), to a food demand chain where power lies with a few giant multinational supermarkets. In Australia, the top two make over 74% of national grocery sales.  As supermarkets become more powerful, they can control what is produced, how much, when and how it is to be produced. Increasingly, only large-scale farms can readily meet these demands, through intensive, specialised, industrialised farming methods. 

Industrial agriculture depends on fossil fuels (via fertilisers, pesticides and petrol for farm machinery) and has devastating impacts at every stage of the food chain: air and water pollution, destruction of ecosystems, loss of biodiversity, soil degradation and water shortages.

Industrial agriculture uses fewer varieties of crops for efficient harvesting, processing and packaging, but increased homogeneity makes crops vulnerable to pest and disease attack, thus increasingly reliant on pesticides.  The manufacture of inorganic fertiliser is the single largest contributor towards agricultural energy consumption (31%), consuming approximately 1.2% of the world’s energy, compared with 3% from aviation.

This monocultural agriculture means biodiversity is lost, with strong correlations between intensive farming and the loss of tens of thousands of animal species.  Today, 75% of the world’s food is generated from just 12 plants and 5 animals.

Industrialised farming means increased crowding of animals, inhumane conditions, and profligate use of antibiotics. Worldwide, our rivers, lakes and ground waters (and hence, human health) are endangered by pollution from nitrogen and phosphorous fertilisers on the soil, pesticides on crops, and use of antibiotics on animals.

Modern fishing is also problematic. Commercial fishing methods are efficient but wasteful, and destroy marine ecosystems. Every year about a quarter of all fish taken worldwide is bycatch and thrown overboard, usually dead or dying. Most of the world’s fish stocks are over-exploited and approaching exhaustion, and 90% of big fish are gone. Fish farms create serious environmental problems: pollution from faeces and chemicals used to treat disease, widespread wild fish stock contamination with escaped farmed fish, and millions of tons of wild fish used as feed.  Three tonnes of wild fish produce one tonne of salmon. A 1000 tonne fish farm produces sewerage waste equivalent to a town of 20,000 people. 

Add to this our increasing demands for processed and packaged food, year round supply and just in time delivery, and the energy requirements multiply, making our current food system unsustainable.
Different production and transport systems have substantially different environmental consequences and carry different amounts of embodied energy and water (the amount of energy and water expended in producing a food). Meat production (particularly beef), for example, is highly intensified and inefficient.

  • Producing a pound of animal protein requires 100 times more water than a pound of vegetable protein. To produce 1kg of meat involves as much water as ten months’ basic household requirements (50 litres per person per day).

  • Every year the Amazon forest is cleared at a rate of 25,000 square kilometres (size of Belgium) to graze cattle and grow soybeans for animal feed. 

  • Food systems expend 10–15 calories of energy for every food energy calorie produced. Each calorie of processed food, moreover, consumes about 1000 calories of energy.

  • Plane transport uses 6 times more energy than road and 30 times that of ship or rail.  Flying a kilo of snow peas 8000 kms from Zambia requires enough energy to keep a 100-watt light bulb glowing for over 40 years.

  • Compared to conventional farming, organic farming has lower pesticide residues, richer biodiversity, greater drought resilience, reduced pollution from nitrogen runoff, avoidance of heavy pesticide and herbicide use, more carbon stored in the soil, and 30-50% less energy for a given yield because it does not use synthetic fertilizers (Singer & Mason, 2006).

Changing food behaviours

Although improved agricultural practices can limit the environmental impact of the food sector, the potential contribution of changing our food choices is even greater. Throughout the world, there appears to be a direct link between dietary preference, agricultural production, and environmental degradation (Karlsson-Kanyama, 1998). Eating more efficiently (i.e., descending) on the food chain, consuming less meat and more plant-based foods, and choosing local produce reduces environmental costs of food production.

There are many environmental and ethical reasons for choosing some foods over others, but changing entrenched behaviours is difficult. How can psychology help to encourage people to make different food choices, thereby reducing the environmental impact of the food they eat?

The most commonly used behaviour change model is Prochaska et al.’s (1992) Stages of Change model.  The first challenge is to interest people in food behaviour modification, and a useful starting place is education.  Several excellent books are listed below (Singer & Mason, 2006, and Suzuki & Dressel, 2002), as well as the Australian Conservation Foundation’s GreenHome Guide ( Social diffusion (the exchange of information and ideas by word of mouth) is another effective, but under-utilised, change tool.  Sharing knowledge with others about the impact of food choices can help them make explicit links between day-to-day behaviour and long-term environmental impacts. 

Several other psychological techniques are useful in promoting sustainable consumption.  Using prompts is one strategy (Linn, Vining & Feeley 1994).  Eco-labels like ‘Fair-trade’ let consumers know when products come from ecologically sensitive management rather than environmentally destructive mainstream practices.  Effective strategies include promotion of behavioural norms (e.g. labelling energy-efficient products with how many people support purchasing such products - Hormuth, 1999); using peer influence to encourage organic food buying; modelling (e.g. ‘nude food’ - where parents provide unpackaged, unprocessed school snacks); and commitment techniques (e.g. asking supermarket shoppers to wear a badge or sticker showing support for recyclable products to increase the likelihood of them actually buying such products - McKenzie-Mohr, 2007).

Many studies, however, report significant gaps between attitude and behaviour.  Gardner and Stern (2002) list common barriers: financial expense (e.g. organic food often expensive¹), institutional barriers (e.g. lack of availability of organic/local food), difficulty of validating information (e.g. Is it better to buy local or organic if I can’t do both? Which products have low embodied energy?), needing to substitute considered thought for routine action (e.g. I always shop here; it’s convenient), and conflict within a household (e.g. partner unwilling to eat less meat).  Of these, cost and convenience emerge as key factors. Then there’s the universal human tendency to dislike sacrifices, and to react against changes perceived as detrimental to ourselves (Oskamp, 2000).  How often have you heard people say “You won’t make me give up my steak”?

Solutions are not about making anyone do anything. Ultimately, we need a paradigm shift to an ecological worldview, where costs are perceived not merely as financial or time-consuming, but environmental and global.  Importantly, people need to make the connection that the environment is an issue of personal as well as collective responsibility - and that they can do something to make a difference.


¹The embodied energy of products is rarely factored into selling prices.  In reality, factory farmed produce is expensive. We all pay in the long term in destruction of the natural environment (Singer & Mason, 2006). With Australians spending on average $4000 on alcohol a year, perhaps it’s a question of priorities.


  • Carlsson-Kanyama, A. (1998). Climate change and dietary choices—how can emissions of greenhouse gases from food consumption be reduced? Food Policy, 23, 277–293.

  • Gardner, G.T., & Stern, P.C. (2002). Environmental problems and human behavior. (2nd ed.). Boston: Pearson Custom Publishing.

  • Goodland, R. (1995). Environmental sustainability in agriculture: diet matters. Ecological Economics 23, 189–200.

  • Hormuth, S. E. (1999). Social meaning and social context of environmentally-relevant behavior: Shopping, wrapping, and disposing. Journal of Environmental Psychology, 19, 3, 277-286. 

  • Linn, N., Vining, J., & Feeley, P. A. (1994). Toward a sustainable society: Waste minimization through environmentally conscious consuming. Journal of Applied Social Psychology, 24, 17, 1550-1572. 

  • McKenzie-Mohr, D. (2007). Accessed April 24, 2007,

  • Oskamp, S. (2000). Psychological contributions to achieving an ecologically sustainable future for humanity. Journal of Social Issues, 56, 373-390.

  • Prochaska, J.O., Di Clemente, C.C., & Norcross, J.C. (1992). In search of how people change: Applications to addictive behaviours.  American Psychologists 47: 1102-14.

  • Singer, P. & Mason, J. (2006). The Ethics of What we Eat. Melbourne: Text Publishing.

  • Suzuki, D. & Dressel, H. (2002). Good News for a Change. Toronto: Allen & Unwin.

  • Underdown, N., Russel, J. & Mung, Z. (2006). The sustainability of European food supply chains. Report published by Ethical Corporation.