A medium fruit weighing 118 grams without the peel delivers roughly 105 calories, 27 grams of carbohydrates, and about 422 milligrams of potassium. The same serving provides around 3 grams of fiber, 14 grams of natural sugars, 1.3 grams of protein, and 0.4 milligrams of vitamin B6, while staying nearly fat-free and containing zero sodium or cholesterol. Because starch converts to sugar as the fruit ripens, the exact breakdown shifts between a green banana and a brown-spotted one.
This guide walks through banana nutrition facts by serving size, ripeness, comparison, and dietary context, and covers how the fruit performs in athletic fueling, diabetic meal planning, and strict low-carb eating.
What a Single Banana Actually Delivers
A medium banana gives you about 118 grams of edible fruit, give or take a few grams depending on the bunch, and that medium size has become the standard reference unit in nutrition databases. Every other serving size is calculated from it, so knowing the starting number makes it easy to scale your intake up or down for calorie and carb targets. Weighing one fruit on a kitchen scale is the fastest way to calibrate your eye for the rest of the week.
Serving-Size Reference at a Glance
The peel adds roughly 35 to 40 percent of total weight, which is why nutrition labels list the “without peel” figure. A large banana can pass 150 grams of edible fruit, while a small one sometimes sits closer to 80 grams.
| Serving Size | Edible Weight | Calories | Carbohydrates | Potassium |
|---|---|---|---|---|
| Small | 81 g | ~72 | ~19 g | ~290 mg |
| Medium (reference) | 118 g | ~105 | ~27 g | ~422 mg |
| Large | 152 g | ~135 | ~35 g | ~540 mg |
| Standardized 100 g | 100 g | ~89 | ~23 g | ~358 mg |
Notice how the calorie line scales almost perfectly with weight: about 89 calories per 100 grams whether you started with a small fruit or cut a large one in half.
Why “Without Peel” Is the Only Number That Matters
Nutrition labels and databases, including the USDA FoodData Central reference, report values for the edible portion only. The peel itself contains some fiber and trace nutrients, but it isn’t eaten in most Western diets, so it doesn’t count toward your daily intake. If a recipe or app quotes a different figure, check whether it includes the peel before you trust the math.
A medium banana is one of the cleanest calorie sources you can find: under half a gram of fat, no cholesterol, and zero sodium.
The Macronutrient Breakdown Beyond the Calories
Those 105 calories in a medium banana come almost entirely from carbohydrates, with protein contributing a small sliver and fat barely a rounding error. Understanding the split between sugars, starch, and fiber is what separates someone who eats a banana mindlessly from someone who picks ripeness on purpose.
Carbohydrates: Sugars, Starch, and Fiber
Out of 27 grams of total carbs in a medium fruit, roughly 14 grams are simple sugars (a mix of glucose, fructose, and sucrose) and about 3 grams are dietary fiber. The remainder is starch, which behaves very differently depending on ripeness. Green bananas hold most of their carbs as resistant starch, a form that resists digestion in the small intestine and travels to the colon, where it feeds gut bacteria.
Dietary fiber lands around 3 grams per medium banana, covering roughly 10 percent of an adult’s daily target. That fiber is mostly pectin, the same soluble type found in apples, which slows digestion and helps moderate blood-sugar response after a meal.
Protein and Fat: A Quiet Profile
Protein sits at about 1.3 grams per medium banana, which is why the fruit rarely works as a standalone protein source. For athletes, that number matters: a banana contributes carbs and electrolytes, but you’ll need a separate protein source to round out a recovery meal. Fat content is under 0.5 grams per fruit, and there’s no cholesterol at all, which makes the fruit an easy add to low-sodium diets.
Glycemic Index: Where Ripeness Changes Everything
The glycemic index (GI) measures how fast a food pushes blood sugar upward on a 0 to 100 scale. A fully ripe yellow banana lands around 51 to 62, putting it in the low-to-medium GI range, while a green banana can drop to 30 or even lower. Overripe, brown-spotted bananas climb higher because their starch has fully converted to simple sugars. For most people this nuance is academic, but if you track blood sugar carefully, choosing a less ripe fruit and pairing it with a source of fat or protein can flatten the spike.
Vitamins, Minerals, and the Compounds That Don’t Make the Headline
Beyond the headline potassium number, a medium banana delivers a strong dose of vitamin B6 and smaller but useful amounts of several other micronutrients. A few lesser-known compounds also show up in the fruit, and they each come with caveats worth knowing.
The Headline Minerals
Potassium is the mineral bananas are famous for: about 422 milligrams per medium fruit, roughly 9 percent of the daily value. Potassium helps regulate blood pressure by counterbalancing sodium and supporting proper muscle and nerve function. Most Americans fall short of the 4,700-milligram daily target, so even one banana moves the needle.
Vitamin B6 is the second standout. A medium banana delivers about 0.4 milligrams, covering close to 25 percent of daily needs. B6 helps convert food into energy, supports brain development, and assists in producing red blood cells, which is why nutritionists often list the fruit among the best whole-food sources.
The Supporting Cast
Smaller but meaningful amounts of other nutrients round out the profile:
- Vitamin C: Around 11 milligrams per medium banana, roughly 12 percent of daily needs, supporting immune function and collagen production.
- Magnesium: About 32 milligrams, contributing to muscle and nerve function, though you’d need other sources to hit the daily target.
- Manganese: Roughly 0.3 milligrams, supporting bone health and metabolism at about 15 percent of daily needs.
- Folate (B9): Around 24 micrograms, important for cell division and especially relevant during pregnancy.
Bioactive Compounds Worth Naming
Resistant starch appears in greener fruit and behaves like a prebiotic, feeding beneficial gut bacteria. Dopamine and tryptophan also show up in small amounts; dopamine in bananas does not cross the blood-brain barrier in meaningful quantities, so it won’t directly affect mood, and tryptophan is present in trace amounts far below what would influence serotonin levels. These compounds are real, but their effects are modest compared to the fruit’s main nutritional contributions.
Those headline vitamins and modest compounds set the baseline, but the same fruit can shift its nutritional profile substantially as it ripens on the counter.
How Ripeness Reshapes the Nutrition Story
The same banana sitting on your counter is chemically different every day. Starch converts to sugar as the fruit ripens, fiber softens but doesn’t disappear, and antioxidant activity peaks after the skin starts spotting. Picking ripeness by goal is one of the most practical nutrition moves you can make with a single food.
Green Bananas: Starch and Prebiotic Power
When the peel is still green or just turning yellow, a banana holds the most resistant starch and the least simple sugar. That starch behaves more like fiber in your digestive tract, supporting the gut microbiome and producing a smaller rise in blood glucose. The trade-off is flavor: green bananas taste starchy, slightly chalky, and far less sweet than fully ripe fruit.
Fully Yellow Bananas: The Familiar Middle Ground
Once the peel turns a clean yellow with no brown spots, most of the starch has converted to sugar. The fiber content holds steady at around 3 grams, but the simple-sugar load climbs to roughly 14 to 17 grams. The glycemic index rises into the low-to-medium range, and flavor hits its sweetest without being overpowering.
Brown-Spotted Bananas: Maximum Sugar, Maximum Antioxidants
When freckles or full brown patches appear on the peel, simple sugar content peaks. Counterintuitively, antioxidant activity also climbs because the fruit is signaling its own ripening process. Digestion is the easiest at this stage, which is why brown bananas disappear smoothly into baked goods and blender recipes.
| Ripeness | Starch | Simple Sugars | Glycemic Index | Best For |
|---|---|---|---|---|
| Green | High | Low | ~30 (low) | Digestive support, low blood-sugar impact |
| Yellow | Medium | Medium | ~51–62 (low–medium) | Snacking, pre-workout fuel |
| Brown-spotted | Low | High | ~70+ (medium–high) | Baking, smoothies, easy digestion |
Match the fruit to your goal: green for slower-digesting carbs and digestive support, yellow for balanced energy, brown-spotted for quick fuel or baked goods. Choosing ripeness strategically is one of the simplest ways to tune banana nutrition facts to your needs without changing the rest of your diet.
Bananas Next to the Other Fruits in Your Kitchen
Bananas are rarely eaten in isolation. A quick side-by-side with the most common kitchen-counter fruits shows where the banana pulls ahead and where the apple, avocado, or orange quietly outperforms it. Picking fruit by goal beats picking by habit, and the numbers make the trade-offs obvious.
Banana vs Apple
A medium apple delivers about 95 calories, 25 grams of carbs, and 4.4 grams of fiber, edging out the banana on fiber. The apple also provides around 8 milligrams of vitamin C, more than the banana. The banana wins on potassium, supplying roughly 422 milligrams compared to the apple’s 195 milligrams, and on vitamin B6, which the apple barely contains. If your goal is gut-friendly fiber, the apple pulls ahead; if you need potassium and B6, the banana is the better pick.
Banana vs Avocado
A medium avocado is a different category of food. It delivers around 240 calories, mostly from 22 grams of monounsaturated fat, plus 10 grams of fiber and 690 milligrams of potassium. The banana’s edge is portability and speed: it requires no prep, no knife, and no ripening window. Use avocados when you want sustained energy and fat-soluble nutrient absorption; use bananas when you need quick carbs and an easy grab-and-go snack.
Banana vs Orange
A medium orange lands around 62 calories, 15 grams of carbs, and 3.1 grams of fiber, with about 70 milligrams of vitamin C, a clear win over the banana’s 11 milligrams. The orange carries less potassium (around 237 milligrams) and almost no vitamin B6. The banana wins on potassium, B6, and calorie density for athletes, while the orange wins on vitamin C and a lower sugar load.
| Nutrient (per medium fruit) | Banana | Apple | Avocado | Orange |
|---|---|---|---|---|
| Calories | ~105 | ~95 | ~240 | ~62 |
| Carbohydrates | ~27 g | ~25 g | ~13 g | ~15 g |
| Fiber | ~3 g | ~4.4 g | ~10 g | ~3.1 g |
| Potassium | ~422 mg | ~195 mg | ~690 mg | ~237 mg |
| Vitamin C | ~11 mg | ~8 mg | ~10 mg | ~70 mg |
| Vitamin B6 | ~0.4 mg | ~0.05 mg | ~0.3 mg | ~0.06 mg |
No single fruit wins on every front. Use the table to pick the fruit that matches the nutrient you’re trying to add, rather than defaulting to the same option every day.
Where Bananas Fit in Real Diets and Who Should Watch the Portion
Bananas work well in some eating patterns and poorly in others. The trick is matching the ripeness, the portion, and the pairing to your specific goal, whether that’s athletic performance, blood-sugar control, or a strict low-carb plan. A few small adjustments can keep the fruit on your menu even when conditions aren’t ideal.
Athletes and Pre-Workout Fuel
For moderate-to-intense exercise, a medium banana 30 to 60 minutes before training delivers fast-acting carbs plus potassium to support muscle contraction and replace some of the electrolytes lost in sweat. Endurance research comparing bananas to commercial sports drinks has found comparable performance outcomes during efforts lasting around 75 minutes, with the added benefit of fiber and no added sugar. After training, pairing a banana with a protein source (Greek yogurt, a scoop of whey, or a tablespoon of nut butter) supports both glycogen replenishment and muscle repair.
Diabetic and Insulin-Resistant Eating
The “doctors say not to eat bananas” concern usually comes down to carb load and ripeness. A fully ripe yellow banana delivers 27 grams of carbs, which can spike blood sugar if eaten alone. Three small adjustments keep the fruit on the menu: choose slightly green bananas for more resistant starch and a flatter glucose curve, pair the banana with a source of protein or fat to slow digestion, and keep portions at half a fruit or one small banana when carb budgets are tight. Standard diabetes guidance from the American Diabetes Association lists bananas among acceptable fruits when portioned into a balanced meal plan.
Keto and Very-Low-Carb Plans
Standard ketogenic diets typically cap daily carbs at 20 to 50 grams, and a single medium banana blows past that ceiling in one sitting. Lower-carb fruit alternatives that fit a typical keto budget include half a cup of raspberries (about 3.5 grams of net carbs), a few strawberries, or a small portion of blackberries. If you miss the convenience, try blending a quarter of a banana with heavy cream, ice, and unsweetened cocoa for a treat-sized serving that stays within budget.
Kidney Concerns and Low-FODMAP Guidance
People with advanced kidney disease often need to limit potassium, and a medium banana’s 422 milligrams can add up quickly when combined with other high-potassium foods like potatoes, beans, and oranges. Your nephrologist or renal dietitian can tell you whether the fruit fits your specific potassium ceiling. On a low-FODMAP plan for irritable bowel syndrome, an unripe (green) banana is usually tolerated, while a fully ripe banana can trigger symptoms in some people because of its higher fructan content.
The “Too Many Bananas” Scenario
Eating three or more bananas a day is generally safe for healthy people, but the calories and carbs add up fast. Three medium bananas push past 300 calories and 80 grams of carbs, which can crowd out other foods and spike blood sugar if your day already includes rice, bread, or pasta. The potassium load (over 1,200 milligrams from bananas alone) sits well within safe limits for most adults, but people on potassium-sparing medications or with reduced kidney function should clear higher intakes with their physician.
Reading a Banana Nutrition Label
Nutrition labels in the U.S. follow FDA formatting, with calories listed first, followed by total fat, sodium, total carbohydrates (with sub-lines for dietary fiber and total sugars), and protein. For a fresh banana, the sodium line will read 0 mg, the cholesterol line won’t appear, and the vitamin section will highlight potassium and vitamin C. When a product uses banana as an ingredient, like banana chips or banana-flavored protein powder, the label reflects added sugar, fat, and processing that change the picture entirely.
Portion awareness and ingredient awareness both matter, so here’s the single takeaway to carry into your next grocery run.
Pair a banana with a source of protein or fat, choose less ripe fruit when blood-sugar control matters, and keep portions aligned with your daily carb budget.
Bottom Line
A medium banana is a calorie-clean, nutrient-dense whole food built around quick carbohydrates, around 3 grams of fiber, and a serious dose of potassium and vitamin B6. The same fruit behaves differently depending on ripeness, comparison, and dietary context, so the smartest move is matching the fruit to your specific goal rather than treating every banana as identical.
FAQ
How many calories and grams of sugar are in one banana?
Weighing in at 118 grams without its peel, a single medium banana carries about 105 calories and roughly 14 grams of natural sugars spread across glucose, fructose, and sucrose. As the fruit ripens and brown spots appear, the simple-sugar share climbs while starch falls, which is why an overripe banana tastes noticeably sweeter than a green one.
What vitamins and minerals does a banana provide?
A medium banana delivers about 422 milligrams of potassium (9 percent of the daily value), 0.4 milligrams of vitamin B6 (around 25 percent of daily needs), 11 milligrams of vitamin C, 32 milligrams of magnesium, 0.3 milligrams of manganese, and 24 micrograms of folate, plus smaller traces of other micronutrients. The standout pair is potassium and B6, with the rest of the lineup filling smaller gaps in your daily intake.
Is it healthy to eat a banana every day?
Most healthy adults can safely add one medium banana a day to a balanced diet without trouble. The fruit delivers potassium, vitamin B6, and fiber without added sugar or sodium, though daily totals depend on your overall calorie and carb budget. If you have kidney disease or take potassium-affecting medications, ask your physician about an appropriate portion.
What is healthier, an apple or a banana?
Both fruits are nutritious in different ways. The banana pulls ahead on potassium and vitamin B6, while the apple provides slightly more fiber and a lower glycemic load. The healthier choice depends on the specific nutrient you want to emphasize in your day.
Why do some doctors say not to eat bananas?
The concern usually comes from specific medical situations rather than bananas being inherently unhealthy. People on potassium-restricted diets due to advanced kidney disease, or those on potassium-sparing medications, may be advised to limit banana intake. Some clinicians also caution against eating fully ripe bananas alone in large amounts if blood-sugar control is a priority.
How does ripeness change a banana’s nutrition?
Starch converts to simple sugars as the fruit ripens, which raises the glycemic index and increases sweetness. Green bananas contain more resistant starch and less sugar, brown-spotted bananas contain the most simple sugar and the highest antioxidant activity, and yellow bananas sit in the middle. Fiber stays relatively constant through all three stages.
