While the most environmentally and health damaging activities require major political, economic, and societal changes, individuals' personal actions can meaningfully decrease their own adverse impact.
“Do your little bit of good where you are; it's those little bits of good put together that overwhelm the world.” - Archbishop Desmond Tutu
Topic 2: Our Diets
Global food production is responsible for a range of environmental harms, including about one-quarter of all GHG emissions, as shown in the following self-explanatory graphics. One of the largest contributions to overall environmental health that individuals can make is in their dietary habits. Project Drawdown ranks Reduced Food Waste third and Plant-Rich Diets fourth of the top 100 solutions for combating climate change.
Individuals can significantly reduce their environmental footprint by eliminating or minimizing their consumption of food products. One simple, highly effective, and cost-saving method is to avoid waste - global food waste alone, about 2/3 derived from households, presently accounts for over 900 million tons (17% of total production) and 8-10% of carbon emissions, at a cost estimated to be over $900 billion a year. “If food loss and waste were a country, it would be the third biggest source of greenhouse gas emissions.”
Understanding the environmental impacts of different foods points the way to better dietary choices. Overall, animal products, especially red meat, have the greatest negative impact; the World Bank reports that animal agriculture produces half of all greenhouse gas emissions, when including associated transportation, deforestation, food storage and of course, belching cows! While an entirely plant-based diet would be optimal, strictly vegetarian or vegan diets aren't widely accepted, so a reasonable compromise is to minimize consumption of the most harmful products. This has the associated major benefit of positive health effects; the EAT-Lancet report “Food in the Anthropocene...” states
Evidence from controlled feeding studies ... and randomized clinical trials supports the conclusion ... that dietary patterns with the following characteristics promote low risk of major chronic disease and overall wellbeing:
protein primarily from plants, including soy, other legumes, nuts, fish or alternative sources of omega-3 fatty acids, several times per week with optional modest consumption of poultry and eggs, and low intakes of red meat, if any, especially processed meat;
fat mostly from unsaturated plant sources, with low intakes of saturated fats, and no partly hydrogenated oils;
carbohydrates primarily from whole grains with low intake of refined grains and less than 5% from sugar;
at least five servings of fruits and vegetables per day, not including potatoes; and
moderate dairy consumption as an option.
The American Heart Association makes essentially the same recommendations.
What other aspects of our diets have important environmental adverse effects?
The poster child for this unsustainable and highly damaging practice is bottled water, especially in plastic, which is an enormous cause of environmental damage, both GHG emissions (plastic production, transportation) and the unmanageable waste it creates. Plastic also has as-yet undetermined potential adverse effects on human health, e.g. from chemicals that may leach into foodstuffs and the recently recognized problem of microplastics, which are now omnipresent in the food chain and have been detected in human bodies.
Non-seasonal and imported foods
Buying produce out of season means that it has been transported different distances under conditions required for its preservation. Tender and readily perishable items, e.g. soft fruits and asparagus, require carbon-intensive air freight. According to the USDA, air shipping uses 50 times as much energy as sea, 33 times rail, and four times more than truck transportation. Buying local produce in-season minimizes the carbon cost of transportation.
Dates on food packaging
Almost all foods are safely edible after the date(s) printed on the package. The USDA has the following explanations and indicates that none of these are safety dates. There are no standards by which manufacturers assign these dates, which are largely arbitrary.
"Best if Used By/Before" indicates when a product will be of best flavor or quality.
"Sell-By" tells the store how long to display the product for sale for inventory management.
“Use-By" is the last date recommended for the use of the product while at peak quality.
“Freeze-By” indicates when a product should be frozen to maintain peak quality.
Eyes and nose are the best guides for how long foodstuffs can be safely eaten and enjoyed.
The role of health professionals
A recent AMA Ed Hub podcast on Sustainable Diets for Personal and Planetary Health presented areas in which health professionals have the capacity to make an impact, based on their community standing and the large number of patients and others they encounter regularly. Examples may include emphasizing the added environmental benefits of a healthy diet, minimizing food waste on a personal and institutional levels, and advocating for healthy foods for distribution.
Talking points for people we interact with:
1) Suggest eating a plant-based diet for at least 3 meals per week.
2) Plan menus and shopping to minimize and ideally eliminate waste.
3) Eat seasonal produce as much as possible, and support local vendors, such as community supported agriculture groups. Avoid high-carbon “foodprint” imports requiring air freight.
Sources and additional information
Food in the Anthropocene: the EAT–Lancet Commission – http://dx.doi.org/10.1016/ S0140-6736(18)31788-4
Clark M, Tilman D. Comparative analysis of environmental impacts of agricultural production systems, agricultural input efficiency, and food choice. Environmental Research Letters. 2017;12(6): 064016.
Willett WC et al. Building better guidelines for healthy and sustainable diets. The American Journal of Clinical Nutrition. 2021;114(2):401–4
Campanale C et al. A Detailed Review Study on Potential Effects of Microplastics and Additives of Concern on Human Health Int J Environ Res Public Health. 2020 Feb; 17(4): 1212. doi: 10.3390/ijerph17041212