If you ask people what they can do about their diet to become more sustainable, most will talk about eating locally sourced food. But how much do food miles matter? What portion of our food’s environmental footprint comes from transportation? And more importantly, how do food miles compare with broader diet and lifestyle changes?

These questions become critically important as we weigh the most impactful changes we can make to our diet and our lifestyles moving forward. After all, knowing which decisions have the largest impacts will provide the clearest path forward as we begin to minimize our own environmental impacts both individually and as a society.

The notion that food miles account for a significant portion of food’s environmental footprint perhaps comes from our conflated mental associations between the tailpipe and emissions more broadly. These associations may lead us to overemphasize food miles above food choices. Choosing to eat locally sourced foods would make a big difference if transportation accounted for a substantial portion of food’s environmental footprint. But for most foods, transportation is responsible for only a small fraction of that footprint.

To understand where the emissions from our food come from, a recent study published in Science in 2018 analyzed data from one of the largest meta-analyses of the global food system and tabulated the relative sources of greenhouse emissions. The dataset represents roughly 38,000 commercially viable farms and 40 different agricultural products from 119 countries, accounting for nearly 90% of global protein and calorie consumption worldwide.*^[1] A visual representation of their findings is shown below.

Download the underlying data for this chart (.csv)^[2]

What we eat has a vastly larger impact on our contribution to climate change than where the food comes from.

Looking closely, the most important takeaway is that there are enormous variances between greenhouse emissions amongst foods, with animal-based foods contributing much more heavily to climate change. Eating a locally sourced diet has minimal impact on reducing greenhouse emissions if that diet is laden with animal products. In fact, with only 4% of overall food production emissions coming from transportation, substituting plant-based foods for meat totalling less than one day’s worth of calories per week reduces emissions more than buying all your food from local sources.*^[3] To go completely plant-based by extension results in monumental reductions in greenhouse emissions.

This is not to say that there are no reasons to support local food systems. From the quality and freshness of foods harvested while ripe and in season, to shunning industrialized systems in favor of supporting local food producers, and yes, reductions in greenhouse emissions, there are many benefits to buying local foods. But at the end of the day, what we eat has a vastly larger impact on our contribution to climate change than where the food comes from. So if you are interested in reducing your own environmental footprint, consider the changes with the largest proportionate impacts – in this case, going whole food plant-based.

References

1. https://science.sciencemag.org/content/360/6392/987 – Reducing food’s environmental impacts through producers and consumers
2. https://ourworldindata.org/environmental-impacts-of-food – Environmental impacts of food production
3. https://pubs.acs.org/doi/abs/10.1021/es702969f – Food-Miles and the Relative Climate Impacts of Food Choices in the United States