A medium ripe banana contains about 3 grams of fiber, which puts it in the moderate range for fruit. It’s not particularly high in fiber compared to berries or pears, but it’s not truly low-fiber either. Where things get interesting is that a banana’s fiber content changes dramatically depending on how ripe it is.
How Much Fiber Is in a Banana
A medium ripe banana has roughly 3 grams of fiber alongside 28 grams of carbohydrates and 110 calories. That 3 grams represents about 10 to 12 percent of the recommended daily intake of 25 to 30 grams. So one banana gets you a modest chunk of your daily goal, but you’d need to eat a lot of bananas to rely on them as a primary fiber source.
The fiber in bananas is roughly 70 percent insoluble and 30 percent soluble. Insoluble fiber adds bulk to stool and helps move things through your digestive tract. Soluble fiber dissolves in water and forms a gel-like substance that can slow digestion and help regulate blood sugar. Bananas contain both, but neither in large amounts per serving.
Ripeness Changes the Fiber Content Significantly
This is the part most people don’t realize. A green, unripe banana contains far more fiber and resistant starch than the yellow banana sitting on your counter. Research from the National Institutes of Health found that unripe bananas contain roughly 18 grams of fiber per 100 grams of fruit when measured with newer, more comprehensive testing methods. That number drops to 4 to 5 grams per 100 grams in ripe bananas and falls further to about 2 grams per 100 grams in overripe, spotted bananas.
The reason is starch. A green banana contains about 21 grams of starch per 100 grams. As the banana ripens, enzymes convert that starch into sugar. By the time the banana is fully ripe, starch drops to about 1 gram per 100 grams. Much of that starch in green bananas is “resistant starch,” meaning your small intestine can’t break it down. It passes through to your large intestine and behaves like fiber, feeding beneficial gut bacteria along the way.
So the answer to whether a banana is low fiber depends partly on when you eat it. A green banana is a genuinely high-fiber food. A ripe banana is moderate. An overripe banana with brown spots is closer to low fiber.
How Bananas Compare to Other Fruits
Stacking bananas against other common fruits helps put the numbers in perspective. A cup of fresh raspberries delivers about 3.3 grams of total fiber (and raspberries are one of the highest-fiber fruits you can eat). Half a small banana provides about 1.1 grams. Fifteen small grapes give you just 0.5 grams. For a full medium banana, you’re looking at roughly 3 grams, which is comparable to a medium apple or orange.
Bananas land squarely in the middle tier. They have more fiber than watermelon, grapes, or pineapple, but less than raspberries, pears, or avocados. If you’re trying to increase your fiber intake, bananas contribute but aren’t the most efficient choice per calorie.
Why Bananas Appear on Low-Fiber Diets
If bananas have a moderate amount of fiber, why do doctors include them on low-fiber and low-residue diets? The answer comes down to how bananas behave in your gut, not just the raw fiber number. Ripe bananas are soft, easy to digest, and don’t leave much undigested residue in the intestines. Clinical low-residue diet guidelines from UCSF specifically list ripe bananas as an approved food alongside applesauce, canned fruit, and pulp-free juice.
Ripe bananas also contain pectin, a type of soluble fiber that can actually help firm up loose stools. A study on children with persistent diarrhea found that green banana and pectin reduced stool weight by about 50 percent and improved the lining of the small intestine. This is why the old BRAT diet (bananas, rice, applesauce, toast) has long been recommended for upset stomachs. The banana’s fiber is gentle enough to be tolerated even when your digestive system is struggling.
The key distinction on low-fiber diets is that the banana must be ripe. Green or unripe bananas, with their high resistant starch content, would defeat the purpose.
What This Means for Your Diet
If you’re trying to eat more fiber, bananas are a decent contributor but not a standout. Eating one medium banana gives you about 3 grams toward your 25 to 30 gram daily goal. Choosing a slightly less ripe banana (still yellow but firm, not spotty) will give you a bit more resistant starch and fiber than a very ripe one.
If you’re on a low-fiber diet for medical reasons, ripe bananas are one of the few fruits you can eat freely. They’re tolerated well after surgery, during digestive flare-ups, and in conditions where minimizing intestinal residue matters. Stick with soft, fully ripe bananas and avoid green ones in this case.
For most people eating a regular diet, a banana is a solid source of potassium and quick energy that happens to carry a moderate amount of fiber along with it. It’s not low fiber in the way that, say, white bread or fruit juice is. But it’s also not the fruit to reach for if fiber is your primary goal.