  Food consumption is one of the biggest contributors to climate change.
However, online grocery shoppers often lack the time, motivation, or knowledge
to contemplate a food's environmental impact. At the same time, they are
concerned with their own well-being. To empower grocery shoppers in making
nutritionally and environmentally informed decisions, we investigate the
efficacy of the Scale-Score, a label combining nutritional and environmental
information to highlight a product's benefit to both the consumer's and the
planet's health, without obscuring either information. We conducted an online
survey to understand user needs and requirements regarding a joint food label,
we developed an open-source mock online grocery environment, and assessed label
efficacy. We find that the Scale-Score supports nutritious purchases, yet needs
improving regarding sustainability support. Our research shows first insights
into design considerations and performance of a combined yet disjoint food
label, potentially altering the label design space.
