Purpose: The nutrition industry is characterized by a high impact on human-made climate change, accounting for as much as 25-30 % of all worldwide greenhouse gas emissions. Deploying eco-labeling to increase people's awareness about the pollution caused by their dietary choices is being introduced in various contexts to promote more sustainable consumption. Design: This experiment aimed to explore the effectiveness of different eco-labeling approaches and quantify the expected effect on consumer behavior. 144 participants was randomly assigned to four groups: a) no label, b) climate-friendly icon for low-emitting choices, c) the CO2 equivalent emissions per meal for all items, and d) a combination icon and numbers. Findings: This survey showed a 9 % reduction in average CO2 equivalent per meal with the certificate alone, 4 % with label and number, but no reduction in the group using only the CO emissions number. Female gender and green attitudes were associated with making a green dietary choice, and the graphical approach was more effective than providing the report as a pure number. Originality: Our results are unique in the sense of comparing impact of the type of labeling realm with an existing commercial label and matching to personal traits with causal modeling.