One cup raw, ripe plantain (about 148g) has 181 calories, 1.9g protein, 0.6g of fat, 47.2g of carbohydrates, 3.4g fiber, and 22.2g sugar. Plantains are a good source of vitamin B6 (pyridoxine), and in their raw form, vitamin C. Green plantains are also rich in resistant starch, a type of fiber that benefits gut health.