A medium banana weighs about 118 grams. It provides 105 calories, 1.3 grams of protein, 0.4 grams of fat, 27 grams of carbohydrate and 3.1 grams of fiber, per USDA FoodData Central. The same fruit carries 422 milligrams of potassium. The NIH potassium fact sheet lists that at 9 percent of the Daily Value. Banana nutrition, in plain terms, is a potassium story wrapped around a carbohydrate story.
Both stories shift over the fruit's short shelf life. A green-tipped banana and a speckled one differ in starch, in sugar and in how the body handles them. That is where ripeness enters the picture.
Banana nutrition at a glance
These USDA values describe one medium banana, roughly seven to eight inches long. Daily Value percentages follow FDA label references. This connects to our earlier piece, Sweet potato nutrition: what one medium baked serving provides.
- Calories: 105.
- Carbohydrate: 27 grams, with 14.4 grams of natural sugars.
- Fiber: 3.1 grams (11 percent of the Daily Value).
- Potassium: 422 milligrams (9 percent of the Daily Value).
- Vitamin B6: 0.433 milligrams (25 percent of the Daily Value).
- Vitamin C: 10.3 milligrams (11 percent of the Daily Value).
- Magnesium: 31.9 milligrams (8 percent of the Daily Value).
- Folate: 24 micrograms DFE (6 percent of the Daily Value).
Potassium: the headline mineral
Bananas owe their reputation mostly to potassium. The NIH sets adult Adequate Intakes at 3,400 milligrams for men and 2,600 for women. Those figures sit apart from the 4,700-milligram Daily Value used on labels. A medium banana covers about one-eighth of the larger figure.
The FDA permits a qualified health claim for potassium. It states that diets with potassium-rich, low-sodium foods may reduce the risk of high blood pressure and stroke. NIH food tables place bananas beside potatoes, tomato juice and oranges among everyday contributors. The NIH also notes that most people in the United States take in less potassium than recommended.
Carbohydrates: starch, sugar and fiber
Of the 27 grams of carbohydrate, about 14 arrive as sugars and most of the rest as starch, per USDA data. The 3.1 grams of fiber ride along with water and potassium. That mix is why banana nutrition reads differently from a sweet snack with similar sugar. The fruit brings structure and minerals with its sweetness. For related coverage, see Chick Fil A nutrition: how to read the menu and order lighter.
Less ripe fruit holds more of its carbohydrate as resistant starch. A review in Frontiers in Bioengineering and Biotechnology calls this starch resistant to enzyme digestion. Green banana pulp runs to roughly half its dry weight in that form.
How ripeness changes the fruit
Ripeness quietly rewrites banana nutrition week by week on the counter. As the peel moves from green to yellow to speckled brown, resistant starch gives way to free sugars. A ripe banana tastes sweeter, mashes softer and bakes moister than a firm one.
The shift shows up in glycemic research. The international glycemic index tables list a mean value of 51 for raw banana. That sits under the low cutoff of 55 on the glucose scale. Values vary with ripeness, and less-ripe fruit tends toward the slower end of the range.
Where bananas fit in eating patterns
Bananas fit most eating patterns, from Mediterranean-style menus to everyday balanced eating. The fruit arrives pre-wrapped. It needs no cooking and carries no added sugar. Those three points count in its favor among whole fruits.
Served with yogurt, nuts or oatmeal, a banana lands in company with protein and fat. Served alone, it still delivers fiber and potassium with its sweetness. It also travels well. No knife, no fridge, no wrapper beyond the peel. Both formats work within an ordinary day of eating.
Conclusion: banana nutrition in context
A medium banana brings 105 calories, 422 milligrams of potassium, 3 grams of fiber and a quarter of the Daily Value for vitamin B6. Ripeness moves sugars and starch around without changing the basic package. As a portable whole fruit, it keeps a firm place in most kitchens.
