Foods Most Harmful For Health Also Greatly Harm Environment

Above: Processed and fried foods. Source: Wikimedia.

Article: Clark, MA, Springmann, M, Hill, J and Tilman, D, 2019. Multiple health and environmental impacts of foods. Proceedings of the National Academy of Sciences, 116(46), pp.23357-23362.


Food is arguably the most basic need of life. Without it, we die. This is true of non-human animals as well. One of the major life functions of all organism is to secure appropriate food and nutrition. Different organisms go about this in different ways.

Early humans are generally believed to have been hunter-gatherers, obtaining their food directly from the wild. Thus, to ensure a stable supply of food, early humans had to be relatively close to their food sources. Often this also mean the early humans had to move periodically in order to follow their sources of food.

One of the most significant turning points in human history was the development of agriculture, or the Neolithic Revolution, which allowed for a year-round supply of ample food in one set place for the first time. No longer having to move seasonally to follow animals to hunt, humans settled in specific areas (where crops could be grown) more or less permanently. These early settlements eventually grew into towns, cities, and entire civilizations. In the process, we as a species adopted a much more sedentary lifestyle than our hunter-gatherer ancestors. Our diet also changed to incorporate dairy, grains, and eventually, meat from animals purpose-raised for food.

This diet and lifestyle, followed (with some modifications, like not eating meat) are followed by the vast majority of people around the world today.

While agriculture has indeed ensured a stable supply of for most of the world, it heavily impacts the environment. As the population of the world has increased, so has the demand for food. As a result, agricultural harm to the environment has increased, not only from actually raising and harvesting the crops, but also from the food preservation and transportation processes that play a significant role in our food habits.

The average human diet today consists of much more grains, meats, sugars, and processed foods than in the past. This, combined with less exercise and physical activity in our daily lives has led to the current global epidemic of obesity and related illnesses.

We know the foods that can cause obesity and other major health problems. And we also know the general impact of various types of agriculture. Recent research by Michael A. Clark and colleagues (published in the Proceedings of the National Academy of Sciences) offers insights into the harmful effects of common foods on human health and the environment.

Research Highlights:

The researchers first identified fifteen common foods in the human diet. They then investigated the effects of increasing the daily intake of each food by one serving size on five common health outcomes (diseases) in adults and on five specific ways agriculture harms the environment.

In figure 1 from the paper (below), the fifteen foods are on the left of panel A and panel B. SSB stands for sugar-sweetened beverage. Panel A shows the relative risk of developing each disease if one additional serving of each food in eaten daily. A relative risk of 1 means no effect. A relative risk less than 1 corresponds with lower risk of developing disease, while greater than 1 corresponds with higher risk of developing disease. Mortality is death, and morbidity is developing the disease(s). Panel B shows environmental impact of producing one more serving of each food, compared to producing a serving of vegetables. A value of .1 equals one-tenth the impact, 1 equals the same impact, 10 equals 10 times the impact, and 100 equals 100 times the impact, and so on.

Source: Clark et al (2019), PNAS.

Of note is the higher relative risk of developing disease and higher relative environmental impact brought about by increased consumption of processed and unprocessed red meat (any meat that’s not fish or chicken) and sugar-sweetened beverages.

Figure 2 from the paper (below) shows the combined health and environmental impacts of each of the fifteen groups, and of all of them combined (‘All Foods’). In this figure, the innermost circle signifies lowest impact, and the outermost circle signifies greatest impact.

Source: Clark et al (2019), PNAS.

Finally, Figure 3 from the paper (below) shows the relative risk of mortality (death) and the average relative environmental impact (AREI) of each food. Any food to the right of the dashed line leads to lower risk of death, and any food the right of the line leads to higher risk of death.

Source: Clark et al (2019), PNAS.

For all its numerous benefits for human nutrition and civilization, agriculture can heavily damage the environment. Not all agriculture is the same though. The procedures needed to raise and process animals and edible eggs are far more impactful to the natural environment than those for growing fruits and vegetables, for example. The negative impacts on human health of foods also differ, with red meat, eggs, and sugar sweetened beverages increases both disease morbidity and mortality. The combined negative effects on the environment and on human health of increased red meat consumption are particularly noteworthy. Just as what is good for the goose may be good for the gander, what is bad for our health seems to be equally devastating for the planet’s health.

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Munim Deen

Munim is an epidemiologist and cartographer. His primary interests are infectious disease outbreaks and their intersection with the environment, public policy, and society at large. A geographic information system (GIS) devotee, he incorporates mapping and spatial analysis into his work whenever possible. A former newspaper columnist, he holds a bachelor's degree in microbiology and a master's degree in epidemiology.

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