AThe diverse range in the supermarket alone makes it difficult to decide what should end up in the shopping trolley and later on the dining table. If you also want to have a healthy diet and also pay attention to the environment, it becomes really difficult. Nutritional information on the packaging helps to eat a balanced diet, but what about the ecological footprint? Is a soy schnitzel better than a ready-made soup or a frozen pizza?
In a recent study, scientists from the University of Oxford analyze for the first time how more than 57,000 products available in supermarkets affect the environment. And as the team led by Michael Clark and Richard Harrington reported in the “Proceedings” of the American National Academy of Sciences, many of the foods and convenience products examined, especially those with a good nutritional composition, have a low environmental impact.
The aspects of climate and environment are important or very important to 84 percent of Germans when it comes to eating. This is the result of the latest nutrition report from the Federal Ministry of Food and Agriculture. At the same time, 27 percent feel less or not at all well informed about the relevant connections. And quite a few consumers feel overwhelmed when it comes to making eco-friendly diet choices. Scientific studies on this topic usually look at the emissions from the respective production of fruit, vegetables, meat or grain. However, supermarket products often consist of a combination of several ingredients, which is why it was difficult to estimate their overall environmental impact.
What about emissions, land and water use?
In order to be able to assess the ecological footprint of just such mixed products, the Oxford-based research team developed their own algorithm, which they used to record the overall impact of more than 57,000 foods and drinks available in the UK retail sector. For example, the scientists quantified how food and its ingredients affect greenhouse gas emissions, land use and water consumption. All these factors were equally taken into account. Since the exact quantities of the ingredients were only known for about three percent of the products, the exact composition had to be estimated on the basis of other data in most cases in order to start the calculations.
However, important factors such as the country of origin or the location of the production facilities were not taken into account because this information was usually not available. However, since these play a crucial role and their absence limits the analysis, the researchers used a stochastic simulation instead: based on various possible agricultural production methods and locations, they determined an average impact factor for a product. However, it remains questionable whether these simulations reflect how enormously different the environmental impacts can be if, for example, blueberries do not come from the region but from Peru.
In any case, from the data collected, the researchers determined a single composite environmental impact score per hundred grams of each product, ranging from 0 (none) to 100 (most impact). “For the first time we have a transparent and comparable method for evaluating the ecological footprint of processed foods with several ingredients,” summarizes co-author Peter Scarborough in a press release the population. “These types of food make up the majority of our supermarket purchases, but until now there has been no way to compare their effects on the environment.” However, when looking at the results of this analysis, it is important to remember that the calculated impact value always increases to refers to a quantity of 100 grams. Portion sizes, which can deviate significantly from this, are neglected.