Mushrooms outperform meat in every sustainability metric: 65% lower carbon emissions, 75% less water, and 87% less land use. Nutritionally, they deliver a complete amino acid profile, B vitamins, and fiber, all without cholesterol or high calories. While they cost $3.08/kg compared to red meat's $12.49/kg, their protein density remains more expensive per gram. The challenge now is scaling production to bring costs down.