Lentils

Lentils lead plant-based protein with 18g per cooked cup and 15g of fiber, plus iron and folate. Although their amino acid profile is incomplete, pairing lentils with grains throughout the day ensures all essential amino acids. They also boast the smallest environmental footprint on this list; for example, producing 1kg of lentils emits 0.9kg CO2e, which is 50% less than the runner-up, whey protein isolate.