More nutritious and healthy diet options can also help the climate, says a new analysis from the University of Leeds.
Our combined dietary habits can be a significant source of greenhouse gas emissions. Worldwide, food production accounts for roughly one-third of all emissions. This isn't very surprising, since everybody needs to eat; but there are little tweaks we can apply to our lives which, added up, can lead to significant benefits for the climate.
New research at the University of Leeds reports that more nutritious, less processed, and less energy-dense diets can be much more sustainable from an environmental point of view than more common alternatives. While "less energy-dense" might sound like a bad thing, calorie content doesn't translate into nutrient content. In other words, many energy-rich foods may actually just leave us fatter and malnourished.
"We all want to do our bit to help save the planet. Working out how to modify our diets is one way we can do that," the authors explain. "There are broad-brush concepts like reducing our meat intake, particularly red meat, but our work also shows that big gains can be made from small changes, like cutting out sweets, or potentially just by switching brands."
Similar analyses of the impacts of dietary options on the environment have been performed in the past. While their findings align well with the conclusions of the study we're discussing today, they focused on broad categories of food instead of specific items. The team wanted to improve the accuracy of our data on this topic.
For the study, they pooled together published research on greenhouse gas emissions associated with food production to estimate the environmental impact of 3,233 specific food items. These items were selected from the UK Composition Of Foods Integrated Dataset (COFID). This dataset contains nutritional data regarding every item on the list and is commonly used to gauge the nutritional qualities of individuals' diets.
The team used this data to evaluate the diets of 212 participants, who were asked to report what foods they ate during three 24-hour periods. In the end, this provided a snapshot of each participant's usual nutritional intake and the greenhouse emissions generated during the production phase of all the items they consumed.
What the results show, in broad strokes, is the environmental burden of different types of diets, broken down by their constituent elements.
According to the findings, non-vegetarian diets had an overall 59% higher level of greenhouse gas emissions compared to vegetarian diets. This finding isn't particularly surprising; industrial livestock farming is a big consumer of resources such as food and water and produces quite a sizeable amount of emissions from the animals themselves, the production of fodder, and through the processing and storage of meat and other goods.
Overall men's diets tended to be associated with higher emissions -- 41% more on average than women's diets -- mainly due to higher meat consumption.
People who exceeded the recommended sodium (salt), saturated fat, and carbohydrate intake as set out by World Health Organization guidelines generated more emissions through their diets than those who did not.
Based on these findings, the authors offer their support for policies aimed at encouraging sustainable diets, especially those that are heavily plant-based. One other measure they are in support of is policy that promotes the replacement of coffee, tea, and alcohol with more sustainable alternatives.
The current study offers a much higher-resolution view of the environmental impact of different food items, but it is not as in-depth as it could be. In the future, the authors hope to be able to expand their research to include elements such as brand or country of origin to help customers better understand what choices they're making. They also plan to include broader measures of environmental impact in their analyses, not just greenhouse gas emissions.
For now, the findings are based only on data from the UK, so they may not translate perfectly to other areas of the globe.
The paper "Variations in greenhouse gas emissions of individual diets: Associations between the greenhouse gas emissions and nutrient intake in the United Kingdom" has been published in the journal PLOS One.