By Amanda Cuéllar with contributions from Colin Beal

The word ‘energy’ usually brings to mind barrels of oil, an electrical outlet, or perhaps a wind turbine. But take a look in your fridge, it is full of energy sources! Although our energy source (plant derived biological molecules) has not changed much since… we started eating, there have been revolutionary changes in how we procure food. While human energy was initially what drove the procurement of food (hunting and gathering, early agriculture and husbandry), we are now increasingly dependent on fossil energy sources to do the grueling labor of growing, harvesting, and distributing our food. This shift to more energy intensive agriculture implies a series of tradeoffs which are best characterized as The Good, The Bad, and The Ugly. The Good is the many benefits we as a society have reaped from the modern food system including cheaper food in terms of time, economic, and resource inputs. The negative environmental effects of resource intensive food production are represented by The Bad. And The Ugly is the paradox resulting from the good and bad tradeoffs in the food system exemplified here in food waste, which is only one example of the ambiguous outcomes of the modern food system. Through this narrative I hope to show that the food system is a complex web of tradeoffs that must be taken into consideration when proposing sustainable changes to food and agriculture.

The GOOD: Since the 1920s agriculture and husbandry in the US has become more mechanized and input intensive (in the form of chemical inputs, mechanization, and transportation), which has in turn increased the total fossil energy requirements of the food system. Greater energy use in food production has provided such modern benefits as well-stocked grocery stores with fresh produce year round and relatively cheap food, which has allowed the average American to dedicate only 9.4% of their disposable income to food in 2010 compared to 25.2% in 1933 (ERS, 2011). More energy intensive agriculture has also freed up time for many of us to do things other than cultivate, harvest and prepare food. In the US agricultural employment has decreased from over 30% of total employment in 1910 to about 2% of total employment in 2005 (USDA, 2006). There have also been advances in the yield achieved with a given level of inputs. From 1948 (around when the use of synthetic fertilizers took off) to 2008 agricultural productivity in the US has increased while inputs have leveled off and then decreased (ERS, 2010). This trend means that agriculture has become less resource intensive per unit output and has allowed us to feed a growing population with a far smaller effect on the environment than would have been possible otherwise.

Source: ERS. Agricultural Productivity in the United States. US Department of Agriculture, Economic Research Service. 2010.

The BAD: There have also been numerous downsides to the increased resource intensity of agriculture; here I will focus on pollution both locally and globally. Locally intensive husbandry emits a variety of air pollutants (including particulate matter, greenhouse gases, and volatile organic compounds) and as well as smell from accumulated manure. Run-off from husbandry operations and crops can also pollute local water sources. From a more global perspective, agriculture and husbandry contribute to global warming through emissions of methane and nitrous oxide (with 21 and 298 times the global warming potential of carbon dioxide, respectively) from fertilizer volatization and decomposition of animal waste. Concentrations of nutrient rich run-off from agricultural activities into waterways contribute to phenomena such as seasonal dead zones in the Gulf of Mexico and other bodies of water. In addition, the food system required about 16% of annual energy consumption in 2007 for agriculture, processing, transportation, storage, retailing, and preparation (Canning et al., 2010). The energy used throughout the food system also produces greenhouse gas emissions and consumes valuable energy resources.

The UGLY: This brings me to food waste, a phenomena that at initial glance can only have negative effects on the food system, yet serves an important purpose for food security. This paradox represents one of many tradeoffs in the food system that must be considered when deciding on sustainability initiatives. Studies place food waste in the US at somewhere between 30-50% of available food (Jones, 2005; Kantor, 1997). In a 2010 publication Michael Webber and I found that the embedded energy in food waste is about 2% of annual energy consumption in the United States, which we consider a lower bound due to a lack of data on food waste and energy use for food production. Food waste represents not only a waste of a valuable human energy source but also a waste of the resources used to produce the discarded food. Although food waste may appear to be a senseless inefficiency, excessive food production does have a purpose. It is impossible to know exactly how many carrots or pork chops consumers will want in a given year and to produce exactly that amount. By producing an excess of food, consumers have greater choice. Excess food production also provides a buffer against disruptions in the food supply. In times of unexpected food shortages we can reduce waste and inefficiencies to make up for shortfalls in supply. There is an optimum level of excess production, though, that provides a level of stability to the food supply without resulting in excessive waste of resources. Agronomists agree that we need to produce 30% more food than necessary to provide an adequate surplus to ensure food security (Smil , 2004). This does not mean, however, that 5 year olds are doing the world a favor by refusing to eat their vegetables and throwing them away. Rather this fact is a means for planning how much food we should produce and to what extent a decrease in food waste can contribute to the sustainability of the modern food system. Although advances in technology can help farmers better predict food demand and consumers to know when food is no longer fit for consumption (and thereby decrease waste), food waste cannot be eliminated completely.

In short, the message of this post is to think critically about the consequences of a change in such a complex system as food and agriculture. Many tradeoffs and biological limitations exist in the system that are not always apparent. There is a method to the current system’s madness, and it is largely driven by consumer demand for convenience. Making agriculture more sustainable also requires a level of buy-in from the general population in terms of what we are willing to sacrifice for a more environmentally friendly system. In addressing the sustainability of the food system we must also look forward to the challenge of feeding a growing population, which is expected to reach 9 billion people in 2050. A sustainable food system must also be able to provide sufficient food for the future population at a price that makes it accessible to all. With this I ask that all of you endeavor to waste less food and also to think critically about sustainability in the food system. The good, the bad, and the ugly exist in all aspects of the food system; endeavor to find them when you think about what is the ‘right’ change for a sustainable food future.


Jones TW. THE CORNER ON FOOD LOSS. BioCycle 2005; 46(7).

Morris, F. ‘Is U.S. Farm Policy Feeding the Obesity Epidemic?’ National Public Radio, Aug. 10, 2011.

Smil V. Improving efficiency and reducing waste in our food system. Journal of Integrative Environmental Sciences 2004; 1(1): 17-26.

ERS. ‘U.S. Farms: Numbers, Size, and Ownership.’ US Department of Agriculture, Economic Research Service. 2007.

ERS. ‘Food CPI and Expenditures: Table 7.’ US Department of Agriculture, Economic Research Center. 2011.

Kantor, L. S.; Lipton, K. Estimating and addressing America’s food losses. Food Rev. 1997, 20 (1), 2.

ERS. Agricultural Productivity in the United States. US Department of Agriculture, Economic Research Service. 2010.

Photo Credit:

The banner used in this post was creased by the author using three pictures (by Rick, Richard Croft, and sporkist) that are all available for use under this Creative Commons license.

About the Author:

Amanda Cuellar is a Master’s student in the Technology and Policy Program at MIT. She received a Bachelor’s degree from the University of Texas at Austin in Chemical Engineering and Plan II Honors in 2009. Her past research focused on the nexus of food and energy. She has done research on the energy potential and environmental effects of converting livestock manure to biogas. Her research has also included a study on the energy embedded in wasted food in the United States. Her current research focuses on the energy, greenhouse gas emission and economic consequences of converting biomass to electric power in existing coal plants. She currently resides in Somerville, Massachusetts.