Because of this wide-reaching impact, scientists have begun to measure just how much dietary change is needed to slow climate change. Food systems are responsible for roughly one-third of all human greenhouse gas emissions. Start by eating only what you need and reducing food waste. Conversations about diet, sustainability, and climate-friendly food policies can also create pressure for systemic improvements in food systems. The future of the planet may be influenced as much by what we buy at the grocery store as by any other action we take to combat climate change.