Global climate change is imminent and largely caused by carbon emissions, a quarter of which may be attributed to the agricultural industry. Although the average consumer may lack control over the practices of an entire industry, they can enact change through what they eat. Plant-based diets, for instance, have a much smaller carbon footprint relative to meat-based diets. By swapping carbon-intensive foods for more environmentally friendly alternatives, consumers can shift market demand and thereby influence underlying large-scale industrial processes. Millennials, in particular, exhibit great potential as changemakers. Extant research suggests that millennials are much more likely, relative to older generations, to believe in climate change and factor in environmental considerations when grocery shopping. Moreover, millennials currently make up the majority of the workforce in the U.S. and therefore have tremendous buying power. Based on insights gathered from user interviews, concept testing, and usability testing, we developed Green Tomatoes, a web platform featuring: (1) a quiz that could assess users' grocery shopping habits and provide potentially actionable insights and (2) several data visualizations intended to inform users on the relationship between food and climate change. Through Green Tomatoes, we hope to empower consumers to make conscious and informed food choices at the grocery store.