However, research on the environmental effect of food behaviors has mostly focused on a limited number of broad food categories. A recent study set out to provide more granular information to how food production affects the environment.
Lead author Dr. Holly Rippin, Ph.D., and her colleagues analyzed GHG emissions of over 3,000 food items. Tying these data to a diet survey, the researchers concluded that healthier diets tend to be more Earth-friendly.
Dr. Rippin and her team added GHG emissions of individual foods to the U.K. Composition of Foods Integrated Dataset. From this, they generated an estimate of GHG emissions for individual diets.
Their findings appear in the journal PLOS One.
Food production, processing, and packaging are responsible for more than one-third of global GHG emissions.
As the authors write in the new paper, “To move beyond general advice at the population level to specific advice tailored to the individual requires measures of environmental sustainability applied to a comprehensive range of specific food items at a more granular level.”
The researchers looked at emissions by dietary pattern, demographics, and the World Health Organization (WHO) recommended nutrient intakes (RNIs).
The team “chose to report on GHG emissions, rather than land and water use, or acidifying and eutrophying emissions, as this is where associations between health and environmental gains have previously appeared strongest.”
Nutritools myfood24 is an online food diary for tracking and analyzing nutritional intake. The current study involved a validation cohort of 212 participants using the myfood24 tool and an interviewer-based 24-hour recall.
The researchers compared the participants’ results against reference measures from biomarkers and RNIs on one to three occasions roughly 2 weeks apart. According to the analysis, meat contributed an estimated 32% of total diet-related GHG emissions.
Beverages including coffee, tea, and alcoholic drinks were associated with 15% of emissions, and dairy contributed 14%. Cake, cookies, and candies may have been responsible for 8% of GHG emissions. The study also found that the diets followed by the men were associated with 41% higher GHG emissions than the diets followed by the women. As the authors explain, this disparity was “driven by differences in meat intake and, to a lesser extent, by GHG emissions from drinks.”
Diets meeting the RNIs, such as those with lower saturated fat and sodium intake, were also lower in meat and produced lower GHG emissions. Dr. Rippin and her co-authors believe that nutritionally optimized diets can have a reduced carbon footprint. They do recognize, however, that trade-offs are inevitable.
The researchers also found that the participants exceeding the RNI for saturated fat and sodium but not achieving the RNI for carbohydrates ate higher GHG emission diets. Moreover, nonvegetarian diets contributed 59% higher GHG emissions than vegetarian ones.