Green lentils are packed with great vitamins and minerals. According to the USDA, a half cup of dried green lentils provides 24g protein, 10g fiber, 80mg calcium, and 4mg iron.   I use green lentils for this recipe because they tend to hold up and retain their shape during the cooking process to give this stew a hearty texture.   Red lentils, on the other hand, can get mushy when cooked for a while. You could substitute brown lentils if you wish, as they cook similarly to green ones.