It’s easy to take bananas and banana calories for granted, but these ubiquitous fruits are low-key superfoods, loaded with essential nutrients that benefit your health on a multitude of levels.
In this article, we will tackle common questions about bananas, such as:
- How many calories does a banana have?
- What nutrients does a banana contain?
- What health benefits are associated with bananas?
Vital Facts About Banana Calories and Nutrients
Originally native to southeast Asia, bananas are now cultivated in tropical locales around the world. Indisputably among the most popular fruits on the planet, bananas vary in color, size, and shape. The variety you’re most likely to find in your local supermarket is the Cavendish, a dessert banana that’s green when unripe and yellows as it matures.
Testing shows that bananas contain potent doses of antioxidants, as well as plenty of cleansing fiber. Bananas contain almost exclusively water and carbohydrates with very little protein and fat. In green, unripe bananas, the carbohydrates consist primarily of starch and resistant starch, which have numerous health benefits. As bananas ripen, however, the starch is transformed into glucose and fructose sugars.
According to the SELF Nutrition Database, the calories in one banana—a medium-sized banana between 7” and 7 and 7/8” long, that is—total up to 105. The calories in one banana do vary, however. For instance, the count for small banana calories, meaning one between 6” and 6 and 7/8” long, is 89.9. So as you can see, if you were to search for an answer to the question “1 banana calories,” you’d likely get more than one answer!
Other important banana nutrition facts, based on a medium banana, are as follows:
- 3.1 grams of fiber
- 1.3 grams of protein
- 0.4 grams of fat
- 24 grams of net carbohydrates
- 14% of your RDI for manganese
- 11% of your RDI for vitamin C
- 10% of your RDI for copper
- 9% of your RDI for potassium
- 8% of your RDI for magnesium
9 Science-Validated Banana Health Benefits
1. Balance Blood Sugar Levels
Bananas contain rich stores of pectin, a type of fiber that gives the fruit its characteristic firm, creamy texture. As bananas ripen, their water-soluble pectin contents increase and their acid-soluble pectin contents decrease, causing the fruit’s flesh to soften. Unripe bananas also contain resistant starch, which functions as an indigestible soluble fiber. Both pectin and resistant starch have been shown to help balance blood sugar levels.
A study published in Gastroenterology, the official journal of the American College of Gastroenterology and the most prominent in the field of gastrointestinal disease, analyzed the effects of pectin on gastric emptying, glucose tolerance, hormone responses, and jejunal absorption of glucose and lysine. Participants followed a low-fiber diet for two weeks, then switched to an isocaloric diet supplemented with 20 grams of fiber daily, either in the form of apple pectin or alpha-cellulose. The researchers found that pectin significantly prolonged gastric emptying time. That means adding foods rich in pectin to your diet can help you stay full for longer.
The researchers behind that study believe pectin’s effect relates to blood sugar levels, too, but have yet to uncover exactly how. A study with several of the same authors, published in the American Journal of Clinical Nutrition, a monthly, peer-reviewed biomedical journal, found that pectin improved glucose tolerance, but again, could not identify a clear mechanism behind that effect.
Another study published in the American Journal of Clinical Nutrition looked at how resistant starch impacts postprandial plasma concentrations—meaning, after-meal blood levels—of glucose, lipids, and hormones. The researchers found that adding resistant starch to a meal resulted in significantly lower concentrations of glucose, lactate, insulin, gastric inhibitory polypeptide (GIP), glucagon-like peptide-1, and epinephrine.
Since bananas rank in the low to medium range on the glycemic index (GI), a measure of how quickly foods increase blood sugar levels, they’re unlikely to cause blood sugar spikes. The GI ranks foods from 0 to 100. Unripe bananas fall at 30, while ripe bananas land at 60. The average GI score for all bananas settles at 51.
People with type 2 diabetes should exercise some restraint when it comes to banana consumption, though. If that applies to you, and you do decide to indulge in a lot of thoroughly ripe bananas, be sure to monitor your blood sugar carefully.
2. Optimize Digestive Health
The loads of fiber bananas offer up also help to optimize your digestive health. As discussed above, bananas contain two main types of fiber: pectin and resistant starch.
According to a study published in Nutrition and Cancer, a peer-reviewed medical journal, eating a high-fiber diet promotes bacterial fermentation of nonstarch polysaccharides. This helps food move smoothly through your digestive system and can even help to protect against colon cancer.
A separate study published in Current Issues in Intestinal Microbiology, a peer-reviewed, international journal, also found that the short-chain fatty acids produced when resistant starches undergo a fermentation process in the large intestine dramatically impact the microflora of your gut, which has a ripple effect on not only your digestive health, but also your overall well-being.
A third study published in Physiological Reviews, a journal published quarterly by the American Physiological Society, analyzed the specifics of how the short-chain fatty acids generated by the fermentation of resistant starch in the large intestine impact your digestive health and more. The authors found that the three primary short-chain fatty acids—acetate, propionate, and butyrate—stimulate colonic blood flow as well as fluid and electrolyte uptake. That study also notes that resistant starch functions as a prebiotic, meaning it feeds the beneficial bacteria that live in your digestive tract.
Plus, a 2016 study published in Nutrients, an open access peer-reviewed scientific journal, found that pectin modulates gut microbiota in ways that reduce inflammation and decrease your risk of developing metabolic disorders. The researchers also found that pectin improved gut barrier function. They concluded that it may play a valuable role both in preventing and treating various digestive and inflammatory disorders.
3. Support Healthy Weight Loss
One of the metabolic disorders that pectin can help to prevent and treat, according to the Nutrients study referenced above, is obesity.
And pectin is only one reason why bananas make a helpful weight-loss aid. They’re quite filling for the amount of calories they contain, and as discussed in the section on blood sugar levels, they help prevent dips that can spur you to chow down on the nearest available snack.
Furthermore, increasing your fiber intake—and as we’ve discussed, bananas are a high-fiber fruit—has repeatedly been linked to weight loss.
Findings published in Nutrition showed that increasing your fruit consumption leads to even more dramatic weight-loss results than increasing your vegetable consumption. The study enrolled 77 overweight and obese individuals and assessed their diets using electronic food records. A clear inverse relationship could be seen between fruit intake and body mass index (BMI), meaning the more fruit participants consumed, the lower their BMIs.
An unrelated study published in The Journal of the American College of Nutrition dug into why an increased fiber intake leads to a lower body weight. The authors theorized that high-fiber foods help you feel full for longer, which leads to a lower total caloric intake. They sought to determine the types and quantities of fiber that most effectively reduce appetite and calorie intake. While they were not able to make any conclusive determinations about the most effective fiber type and dose, it’s clear that dietary fiber intake can help to lower body weight.
4. Protect Overall Heart Health
Despite its paramount importance, many people fail to meet the recommended dietary intake for potassium, according to a Food Surveys Research Group Dietary Data Brief. Bananas can help you change that. A medium banana contains 118 grams of potassium, which totals up to 9% of your daily recommended intake.
Studies clearly show that eating a potassium-rich diet can help you lower your blood pressure. According to findings published in JAMA: The Journal of the American Medical Association based on a meta-analysis of 33 randomized, controlled trials that enrolled a total of 2609 participants, potassium can significantly reduce blood pressure. The authors found that potassium reduced both systolic and diastolic blood pressure, and concluded that increasing potassium intake could be a valuable method for both preventing and treating hypertension.
Research published in Current Hypertension Reports, which shares in-depth articles by international experts, also found a clear link between increased dietary potassium intake and lower blood pressure levels. The researchers concluded that by increasing your potassium intake to 4.7 grams per day, you could substantially lower your risk of future cardiovascular disease, with estimated decreases of between 8% and 15% for your risk of stroke and 6% to 11% for your risk of heart attack.
An article published in the Journal of the American College of Cardiology, a peer-reviewed medical journal, went deeper into the ways potassium can lower your risk of stroke as well as other adverse cardiovascular events. According to a systematic search that evaluated data from 247,510 participants, a 1.64-gram increase in potassium intake led to a 21% reduction in stroke risk. The benefits for lowering your risk of coronary heart disease and total cardiovascular disease were less clear, but promising. The researchers concluded that a higher consumption of potassium-rich foods can be a helpful strategy for preventing vascular diseases.
Bananas also contain a noteworthy dose of magnesium. According to an article published in Clinical Kidney Journal, low magnesium levels are associated with hypertension, and increasing your magnesium consumption appears to prevent high blood pressure.
5. Deliver Potent Antioxidants
As mentioned previously, bananas are a phenomenal source of dietary antioxidants. A study published in Food Chemistry analyzed antioxidants found in commercial bananas with a focus on gallocatechin, which the authors found had impressive effects.
Separate findings published in the Journal of Agricultural and Food Chemistry, a weekly peer-reviewed scientific journal, looked at another antioxidant found in commercial bananas: dopamine. They found dopamine had an impact comparable to antioxidants previously identified as extremely potent. The authors found high levels in banana flesh as well as in banana peel. Ripeness did not lower antioxidant levels, which averaged between 2.5 and 10 milligrams in the flesh.
As you most likely know, testing has revealed that antioxidants benefit your health and well-being in a multitude of ways. According to one review of the mechanisms behind the impact of antioxidants, they can help to lower your risk of cardiovascular diseases, neurodegenerative diseases, and even certain kinds of cancer. They can also prevent DNA damage and may even have anti-aging properties.
One important point of clarification, however. The dopamine in bananas does not appear to have any effect on your mood. While it does act as a feel-good chemical in your brain, the dopamine in bananas does not cross the blood-brain barrier, so it simply acts as a powerful antioxidant.
6. Increase Insulin Sensitivity
Research on the ability of bananas to improve insulin sensitivity is ongoing, but what researchers have uncovered so far is quite exciting. Insulin resistance contributes to the progression of numerous diseases, including type 2 diabetes.
One of the earlier investigations on the subject was published in 2005 in the American Journal of Clinical Nutrition. Scientists from the Oxford Centre for Diabetes, Endocrinology and Metabolism at the University of Oxford found that dietary supplementation with resistant starch—something bananas contain loads of, especially when unripe—appeared to have the potential to improve insulin sensitivity.
In 2010, another team of British researchers published findings in Diabetes Medicine that confirmed resistant starch impacts insulin sensitivity. Their single-blind, randomized, parallel nutrition intervention looked at the effects of adding 40 grams of resistant fiber per day to an individual’s diet. Compared to subjects in the placebo group, those who received the fiber intervention showed markedly improved insulin sensitivity at the conclusion of the study.
More research is needed to understand exactly why resistant starch has this effect so individuals can better understand how to use foods high in resistant starch, like bananas, to improve insulin sensitivity.
8. Boost Kidney Function
You probably knew this before you began reading this article, and if you didn’t, we already mentioned it, but just to underline the point—bananas are, in fact, a good source of potassium. Many underestimate the importance of potassium, which functions as both a mineral and an electrolyte, but that’s a mistake. Research has linked a potassium-rich diet to a number of health benefits, including healthy kidney function.
A 2005 study published in The International Journal of Cancer, a peer-reviewed medical journal covering experimental and clinical cancer research, looked at the relationship between fruit and vegetable consumption and kidney health (specifically, renal cell carcinoma). Based on data gathered over the course of 13+ years from over 61,000 women, the researchers concluded that eating bananas between two and three times each week can lower your risk of kidney cancer by 33%. Bananas showed the strongest protective effect of any of the fruits analyzed.
An earlier study on the connection between diet, potassium intake, and kidney function published in Epidemiology found, among other things, that eating bananas between four and six times weekly can lower your risk of developing kidney disease by close to 50%.
9. Improve Athletic Performance and Recovery
If you’re interested in improving your athletic performance, especially your endurance, or looking for ways to speed up your recovery after intense exertion, you should definitely increase your banana intake.
Not only do bananas contain plenty of nutrients and easily digested carbohydrates to fuel you, but according to high-quality research, they can also help your body perform more efficiently and even prevent muscle cramping.
According to a 2012 study published in PLOS One, a peer-reviewed open access scientific journal, bananas offer even more benefits for athletes than specially designed energy drinks. The authors saw clear benefits in terms of performance as well as post-exercise inflammation, oxidative stress, and innate immune function.
Researchers have yet to determine exactly why bananas help to prevent exercise-related muscle cramps and soreness, but believe it may have to do with their potassium content, which helps to rebalance your electrolyte profile.