 Metabolic Bone Disease causes soft bones, stunted growth, permanent bone deformities, frequent broken bones, loss of limbs and ultimately, death.Although they will consume a wide variety of foods if offered, green iguanas are naturally herbivorous and require a precise ratio of minerals (2 to 1 calcium to phosphorus) in their diet.The best food source for the Iguana is dark green leafy greens such as collard greens, turnip greens, dandelion greens and small portions of kale, which is too high in phosphorus for everyday use.