Reducing the Environmental Impacts of Diet

Food production and greenhouse gas emissions

Researchers at the University of Minnesota labeled the convergence of 1) diets increasing in calories and animal products, 2) increasing prevalence of chronic diseases, and 3) increasing environmental deterioration as a global trilemma. These three trends bode ill for people and the planet. Global food demand (measured as that which enters households) has risen substantially, especially in developing counties. From 1961 to 2013, per capital demand increased by more than 50 percent in South Asia and Southeast Asia and by 13 percent in Europe. Much of the increase in calories has come from animal products, sugars and sweeteners, and ultra-processed foods. A rise in the prevalence of chronic diseases, such as type 2 diabetes and obesity, accompanied the increase in global per capita food demand, especially in countries that have greatly increased their consumption of sugars, sweeteners, and animal products. Demand for animal products is expected to rise most dramatically in developing countries. Food production accounts for 25-33 percent of global greenhouse gas emissions. Global food production is forecast to increase by 60 to 100 percent from 2005 to 2050, with animal products accounting for much of that increase.

Several paths can lead to healthier and more environmentally sustainable diets, including more efficient fertilizer use, integrated farming practices, tax policies, and reduced food waste. The path with the highest and quickest payoff might be a substantial decrease in ruminant animal (cattle, sheep, goats) meat production and a substantial increase in whole fruit, vegetable, and legume production. Such a change over time could improve diet quality, reduce the risk of chronic diseases, and reduce environment damage (less greenhouse gas emission, less fertilizer use, less water pollution). Making these dietary changes would require major adjustments on the part of global citizens.

Substitute Chicken for Beef

Climate change increasingly affects the ways in which we conduct our lives, including what we eat. Recent research suggests that food production, processing, and distribution account collectively for a substantial proportion of US greenhouse gas emissions. Explaining to the public ways to reduce greenhouse gas emissions is challenging due to the potential complexity of proposed actions. Researchers at Tulane University and the University of Michigan investigated the greenhouse gas production and water use effects of substituting just one food item for another item in a daily diet. Many Americans might regard such as approach as easy to understand and practical. Dietary intake data came from 16,800 participants in the National Health and Nutrition Examination surveys from 2005-2010.

The researchers found that beef products accounted by far for the largest potential reduction in greenhouse gas emissions. For example, substituting poultry or pork for beef would reduce greenhouse gas emissions and water use by an estimated 48 and 30 percent, respectively. Across the entire sample (including participants who did not report eating beef products), this substitution would reduce greenhouse gas emissions and water use by an estimated 10 and 6 percent, respectively. Other dietary items whose substitution would result in much lower greenhouse gas emissions included peas for asparagus, cod for shrimp, and soy milk for cow milk. Dietary substitutions that would lead to substantially less water use included peas for asparagus, peanuts for almonds, and Brussels sprouts for broccoli. Thus, the simple replacement of beef with chicken might result in a noteworthy drop in greenhouse emissions and water use in the US.

What Do 21 Brits Think About Sustainable Diets?

Numerous studies find that global diets are not sustainable in terms of their environmental impacts, not to mention other considerations such as nutritional adequacy, accessibility, and chronic diseases. Researchers conducted in-depth interviews with 21 adults from age 23-58 in the Dorset area of the UK. Responses of the participants to the open-ended questions were analyzed with respect to understanding sustainable diets and making dietary changes.

Four themes for understanding sustainable diets emerged: 1) consistency with the UN Food and Agricultural Organization’s definition, 2) multiple benefits, 3) unsure, and 4) competing interests. Participants mentioned actions that generally aligned with FAO’s definition of sustainable diets. Multiple benefits of sustainable diets included better health, lower greenhouse emissions, and better animal welfare. Notwithstanding the preceding, participants were often unsure of exactly what sustainable diets entailed and what actions would lead to more sustainable diets. Participants also identified competing interests, such as sacrificing taste and convenience to achieve sustainability.

What can you do? Current evidence suggests reducing your beef consumption and increasing that of non-ruminant animal products (pork chicken) and legumes such as beans.


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