Eating more sustainably by trimming off the excess—what about discretionary food?

The notion of sustainable food consumption has acquired a broader definition in recent years: as the incidence of obesity and other diet-related chronic diseases rises, “sustainable” consumption has come to refer to not only planetary health but also human health. The food sustainability debate has thus far centered largely on reducing red meat consumption. However, this paper argues that we cannot seek to align health and environmental objectives without considering the role of discretionary food, defined as foods and drinks not necessary to provide the nutrients the body needs, such as soft drinks and sweets. These foods are typically highly processed and high in sodium, sugar, and saturated fat, and while their negative impacts on health are well documented, their broader environmental sustainability impacts deserve more attention. This is particularly true given that their affordability and palatability is a result of a food system that aggressively promotes the overconsumption of such products. The paper combines unique nutrition and expenditure data from Australia, including a detailed classification of discretionary products, along with environmentally extended input-output analysis to estimate the life cycle environmental impacts of discretionary food consumption across diverse socioeconomic groups. The novelty of the approach lies first in a multi-indicator approach to measuring sustainability, simultaneously taking into account water use, energy use, carbon dioxide equivalent, and land use. Second, the approach accounts for equity considerations and distinguishes, on the basis of dietary intake, whether discretionary foods can be simply eliminated (excess consumption) or require substitution. The latter is typically the case for poorer socioeconomic groups who are currently malnourished because discretionary food has replaced core foods. On average, discretionary foods account for a significant 30 to 40% of overall diet-related water use, energy use, carbon dioxide equivalent emissions, and land use, although these percentages vary depending on the types and quantities of foods consumed by each socioeconomic group. These results suggest that a reduction in the production and consumption of discretionary foods should be seen as an essential priority for a sustainable food system. We should continue to explore ways to encourage reduced discretionary food consumption, but more importantly, we should also consider proactively reducing production. A general call for divestment away from such food products, which are harmful to health and create an unnecessary burden on the environment,