Obesity, which is the extreme form of excess body fat in humans, has been increasing rapidly worldwide in recent decades. In addition to being associated with numerous major, and often deadly, diseases including type two diabetes, heart disease, cancer, and premature death, 1 there is a complex relationship between mass obesity and the environment. That is, environmental factors are contributing to the obesity epidemic and this epidemic is affecting the environment.
For example, rising temperatures and increased precipitation in some regions may contribute to higher obesity rates by reducing physical activity. Also, an increased occurrence of extreme weather events can make vegetables and fruits less available and more expensive, thus encouraging consumers to replace them with less nutritious and more fattening foodstuffs.2 Moreover, some studies have shown that environmental toxins can also contribute to obesity by affecting gene expression and the body's metabolic processes.3
Changes in the built environment have also been contributing greatly to the worldwide surge in obesity. In much of the developed world the rapid increase in urban sprawl has made walking more inconvenient and resulted in more automobile use. In many developing countries walking even moderate distances is becoming less common due to mass migration from rural areas to high density urban areas in which walking is less pleasant, more difficult and more dangerous due to extreme traffic congestion and also sometimes to higher urban temperatures and severe air pollution.
One of mass obesity's effects on the environment is to increase energy consumption. This is because of increased fuel consumption for transportation for heavier individuals and perhaps also because of increased use of automobiles and other powered transportation instead of walking. It is also a result of the greater food consumption and the resulting increases in fuel required for producing and transporting such increased food.
This increased energy consumption is estimated to result in increased greenhouse gas emissions, by roughly 20 percent as compared with normal weight persons. The result would be equivalent to about 1.6 percent of total greenhouse gas emissions.4
Widespread obesity can also add to environmental pollution from the increased waste resulting from added food consumption and food packaging. Obesity and its related health issues can also lead to greater use of medical resources and materials, which likewise affect the environment through increased energy consumption and waste production. Moreover, they can divert valuable resources, including managerial talent and financial resources, from environmental protection and restoration efforts.
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1
According to the World Health Organization, in 2022 worldwide adult obesity was more than double that of 1990. 2.5 billion adults (18 years and older), or about 43 percent of all adults, were overweight, of which 890 million were obese. Moreover, adolescent obesity has soared to about four times the 1990 level, with more than 390 million children and adolescents aged five to 19 years being overweight in 2022, including 160 million who were obese. Obesity is an extreme form of overweight, defined as a body mass index (BMI) for adults equal to or greater than 30, as compared with 25 or greater for overweight. Obesity and overweight, World Health Organization,
https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight.
2 Such low quality foods are some combination of high fat, high sugar, high salt, and high energy density. They are also typically low cost and lacking in micronutrients.
3 See, for example, Toxic Tuesdays CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm, https://chej.org/epigenetic-toxicity.
4 The Obesity Society, Study suggests obesity associated with greater greenhouse gas emissions, 2019, https://www.eurekalert.org/news-releases/620389.