Learn how many calories , carbs, protein , fiber, and other nutrients are in one banana (without peel). See the glycemic index, glycemic load, insulin index, and mineral coverage of bananas. Protein: A medium-sized banana has around 1.3 grams of protein, adding around 5 calories . Fat: Bananas contain little fat, approximately 0.3 grams in a medium-sized banana with little caloric value. 1 medium banana (Raw) contains 105 Calories . The macronutrient breakdown is 93% carbs, 3% fat, and 4% protein. This is a good source of potassium (9% of your Daily Value) and vitamin b6 (33% of your Daily Value). Discover the health benefits of bananas , from aiding post-workout recovery to supporting heart health and easing digestive issues. Learn why this nutrient-rich fruit should be part of your diet.