Growing, harvesting, processing, and transporting our food takes about 17% of all the fossil fuel used in the United States. With the ambitious goal of reaching net zero emissions by 2050, consumers are searching for foods that require fewer fossil fuels. Is this realistic?

Quantifying Energy Used for Food

We recently read How the World Really Works, the most recent book by Vaclav Smil, a distinguished Professor Emeritus at the University of Manitoba. Smil has published 47 books and more than 500 papers on the research in energy environmental and population change, food production, history of technical innovation, risk assessment, and public policy. Bill Gates considers him one of his favorite authors.

In his latest book, Professor Smil explored the improvements the world has made since the early 1800s. He explains “In two centuries the human labor to produce a kilogram of American wheat was reduced from 10 minutes to less than two seconds.” He also talks about the importance of fossil fuels and the world could not provide enough food to feed all of us without them.

Smil also delves into food production and its associated energy use. In fact, he had the patience to calculate how much energy it takes to make a loaf of sourdough bread, raise a chicken, grow a tomato, and eat seafood. He averaged out an itemized estimate using production numbers around the globe.

This sounds like a painstakingly long and detailed effort, with considerations for crop and livestock cultivation; facilities management; processing, production and packaging; and all distribution required along the way. But the results were interesting and surprising!

Bread’s Energy Journey 

Sourdough bread is a staple around the world.

The energy it takes to plant, grow, and harvest wheat is crucial in its production. After the wheat is harvested, it is trucked or goes by rail to the mill to be made into flour.

The initial stages of sourdough preparation require the activation and maintenance of the starter culture, which demands consistent temperature control.

Additionally, mixing, kneading, baking and the use of ovens and other kitchen appliances all contribute to energy consumption.

The energy required throughout this journey for a 2.2 pound loaf of sourdough bread is just about 8 ounces of diesel fuel.

Crude for Chickens

Raising chickens involves a fascinating blend of traditional agricultural practices and modern energy considerations.

To maximize production, it is critical to maintain a suitable environment for the birds. They must be fed the right mixture of grains, minerals, and vitamins.

The utilization of electricity for consistent temperature control, ventilation, and lighting, especially in large-scale operations, underscores the intrinsic relationship between energy usage and the well-being of the birds.

Once the chicken is fully grown the birds are transported to the processing facility which turns them into breasts, thighs, and other cuts for the grocery store.

The entire energy for 2.2 pounds of processed chicken is about 11 ounces of diesel.

Holy Tomato!

Tomatoes can require many factors and sources of energy, depending on whether they are grown indoors or out.

Photosynthesis uses the sun’s energy to grow tomatoes outdoors for over eight months. Yet for the 35% of global tomatoes grown indoors, the energy inputs are significantly more because of the substantial energy required to provide heat, light, and nutrients, not to mention the energy needed to make the greenhouse itself.

But even tomatoes grown outdoors require crude oil to make the plastic clips, wedges, sheets, and gutter arrangements for successfully growing a tomato crop.

The energy utilized in production encompasses diverse inputs, from solar energy and traditional machinery to electricity and embodied energy, making its energy calculation highly complex.

The answer for this beloved fruit is not simple, but Smil calculated that, growing 2.2 pounds of tomatoes uses about 21.9 fluid ounces of diesel fuel, on average.

Fuel for Farmed Salmon 

On average, the energy consumption for seafood production is relatively high.

It takes approximately 23.6 ounces of diesel per 2.2 pound serving, just slightly more than the energy needed for tomatoes.

For example, salmon, a popular seafood choice, is predominantly farmed, which involves significant energy expenditure for fish feed production, transportation to farms, and ultimately to consumers.

Unless sourced locally from specific regions like Chile, Norway, Scotland, or Western Canada, considerable energy is expended in the entire process from farm to table.

Of course, one can imagine the amount of fuel used to catch, freeze, and transport wild-caught fish. Professor Smil suggests that opting for sardines, which are rich in omega-3s and have lower environmental impacts, can be a more sustainable choice.

Is Energy Estimation Possible?

We were shocked when we found out that raising 2.2 pounds of chicken required just a third of the energy needed to cultivate the same weight of tomatoes. This proves that our food system is much more complicated than it appears.

We wrote about climate conscious eating and pointed out that it is not just about the energy used, we have to also consider water.  To grow just one ounce of nuts takes anywhere from 3.2 gallons to a whopping 28.7 gallons for almonds.

Farming takes multiple kinds of energy. Human energy – plain old hard work and effort.  Solar energy – sunlight for photosynthesis.  Wind – for pollination.  And just as important, fossil fuel energy, including diesel and gasoline for farm machinery, plant equipment, and transportation.

Used appropriately, energy increases productivity and distribution across our food system, therefore increasing profitability for farmers. Without that energy, the whole system collapses.

End of story, turn out the lights, dinner is over.

The complexities of our food system are vast. As we push our cart through the grocery aisle, how do we really know whether the food we eat is farmed sustainably and uses energy and water responsibly? Are you curious?

1. Would you pay more to know exactly how much energy and water was used to make the food you are eating?
2. Would you like to see it on a label?
3. Would it affect your food choice?