14 Side Effects Of Eating Too Many Bananas

From constipation to drowsiness - this tropical fruit can affect your health in many ways.

Medically reviewed by Reda Elmardi, RDN Reda Elmardi Reda ElmardiRDN facebook_iconinsta_icon
Written by , B.Desgn, ISSA Certified Specialist In Fitness & Nutrition Tanya Choudhary B.Desgn, ISSA Certified Specialist In Fitness & Nutrition twitter_icon Experience: 2 years
Edited by , BSc, Professional Certificate in Food, Nutrition and Health Ravi Teja Tadimalla BSc, Professional Certificate in Food, Nutrition and Health Experience: 8 years
Fact-checked by , BPharm, Certified Health & Wellness Coach Moksha Gandhi BPharm, Certified Health & Wellness Coach Experience: 2 years

Bananas are a favorite of many. They are replete with nutrients. But can you eat too many bananas? The answer is no, because excessive consumption of bananas may affect your health. Here, we have explored the side effects of bananas.

Bananas help alleviate certain key health concerns and are deemed safe enough to be given as one of the first solid foods to babies. So what then could go wrong when you consume bananas? Maybe consuming too much of it? Read on to find out the 14 possible risks associated with excess consumption of bananas.

protip_icon Know The Flip Side: Bananas

Short-Term Effects
Tooth decay, allergies, weight gain, ragweed allergies, constipation, abdominal pain, weight gain, and drowsiness.

Long-Term Effects
Aggravates the risk of type 2 diabetes, hyperkalemia, and migraine.

Drug Interactions
Overconsumption may affect antihypertensive (beta blockers and ACE inhibitors), antibacterial, and diuretic medications.

When To See A Doctor
If you experience excessive cramping, throat irritation, and wheezing, or kidney dysfunction.

Side Effects Of Bananas

  1. Weight Gain
  2. Migraine
  3. Hyperkalemia
  4. Tooth Decay
  5. Drowsiness
  6. Nerve Damage
  7. Ragweed Allergy
  8. Hypersensitivity In Patients Allergic To Latex
  9. Respiratory Problems
  10. Abdominal Pain
  11. Anaphylactic Shock
  12. Constipation
  13. Gas
  14. Risk Of Type 2 Diabetes

1. Weight Gain

Bananas may cause weight gain
Image: Shutterstock

Agreed that bananas, in comparison to your favorite box of cookies or crisps, have lesser calories, but, they still have enough calories to make you put on weight. That is if you don’t keep a tab on your portion sizes.

A medium-sized banana contains 105 calories. That, in comparison to a medium-sized orange (62), a bowl of diced watermelon (45), or a cup of grapes (62) is a lot higher. So, if you’re looking for a low-calorie snack to indulge in every few hours, bananas may not be the best choice. Instead, fruits and veggies with high water content like watermelon, strawberries, cantaloupe, peaches, cucumber, lettuce, zucchini, cabbage, etc. make for better snack choices. They have fewer calories and high fiber content to keep you full for long.

The banana is a great fruit that can be eaten in many ways. However, if you eat too many bananas, you may gain weight. This is due to the high amount of calories contained in the fruit. A single large banana contains about 100 calories. If you eat two bananas per day, you would consume 200 calories each time. That’s almost 500 extra calories per day! Here’s when the question of how many bananas I should eat a day arises. The answer is it is dependent on your calorie budget per day and your weight loss or weight gain goal.

2. Migraine

Bananas may cause migraine
Image: Shutterstock

If you’re often troubled by excruciating migraine attacks, you may want to avoid including bananas in your daily diet. Tyramine, a substance found in many foods like cheese, fish, meats, and bananas is a trigger for migraine headaches (1). Since banana peels contain ten times more tyramine than banana pulp, be extra cautious about removing the stringy pieces of peel from the fruit before eating it.

3. Hyperkalemia

Bananas may cause hyperkalemia
Image: Shutterstock

Hyperkalemia is a condition caused due to excess potassium in the blood and is identified through symptoms like uneven pulse rate, nausea, and irregular heartbeat that can even lead to heart attack. Excess consumption of potassium may cause hyperkalemia in adults. There are certain diet plans like the GM diet that recommend excess intake of bananas on certain days. If you follow such diets, you could just be calling for trouble.

protip_icon Did You Know?
Bananas contain a minute concentration of radioactive potassium. One banana can emit a minuscule amount of radiation (0.1 microsieverts).

4. Tooth Decay

Bananas may cause tooth decay
Image: Shutterstock

Being high in starch, bananas can cause serious tooth decay if you don’t maintain proper dental hygiene.

A 2021 study published in the Plos One research journal noted the levels of nutrients, such as dietary fiber and sugars in bananas taken from various retail stores, at different stages of ripeness, as shown in the graph below.

The graph illustrates that once the banana ripens, its starch content significantly decreases but its sugar content rapidly rises. Thus, you can prevent tooth decay from banana starch by avoiding excessive intake of unripe and slightly ripe bananas.

Dietary fiber, starch, and sugars in bananas at different stages of ripeness in the retail market

Source: Dietary Fiber, Starch, and Sugars In Bananas At Different Stages Of Ripeness In The Retail Market

According to certain studies, bananas can be even more detrimental to your oral health as compared to chocolates, red licorice, and chewing gum (2). Starches dissolve slowly in the mouth whereas sugars dissolve quickly. Therefore, when you consume foods like bananas, their particles rest between the teeth for about two hours and thus attract more bacteria, resulting in more cavities.

5. Drowsiness

Bananas may cause drowsiness
Image: Shutterstock

Always thought that beginning your day with a banana was a great idea? What you probably didn’t know was that bananas can make you feel drowsy, even if you’ve just started the day. They are rich in tryptophan, an amino acid that can reduce your mental performance and reaction time, apart from making you feel sleepy (3). Bananas also contain high doses of magnesium, a mineral that aids muscle relaxation. These properties, however, make them a good snack before bedtime.

6. Nerve Damage

Bananas may cause nerve damage
Image: Shutterstock

Since bananas contain vitamin B6 in high amounts, their overconsumption can result in nerve damage. Very high consumption of vitamin B6 supplements without prescription can result in nerve damage (4). However, the possibility of nerve damage through banana consumption seems rare unless you are a bodybuilder with a banana obsession or if you are participating in a banana eating competition.

7. Ragweed Allergy

Bananas may cause ragweed allergy
Image: Shutterstock

Ragweed allergy is a condition that causes your immune system to react when you inhale ragweed (weeds that grow throughout the United States) pollen grains. A person suffering from this allergy displays symptoms like swollen lips, irritated throat, swollen tongue, etc. People who are already suffering from ragweed allergy might experience similar symptoms upon consumption or even handling of bananas. However, limited data is available to prove these claims.

8. Hypersensitivity In Patients Allergic To Latex

Bananas may cause hypersensitivity in allergy patients
Image: Shutterstock

As per a study conducted by the Annals of Allergy, Asthma, and Immunology, those individuals who are allergic to latex display hypersensitivity to bananas too (5). Common allergic reaction symptoms may include wheezing, a runny nose, coughing, itchy throat, and watery eyes.

9. Respiratory Problems

Bananas may cause respiratory problems
Image: Shutterstock

Another problem that is an offshoot of ragweed allergy is inflammation. It might constrict airways and cause respiratory problems like a difficulty in breathing. In severe cases, this might also affect swallowing (6).

10. Abdominal Pain

Bananas may cause abdominal pain
Image: Shutterstock

If you indulge in bananas that aren’t ripe enough, you may end up with a severe stomach pain. You may also experience nausea along with the abdominal pain. Unripe bananas contain a high amount of resistant starch that takes a long time for your body to digest. You may also experience immediate vomiting or diarrhea.

11. Anaphylactic Shock

Bananas may cause anaphylactic shock
Image: Shutterstock

Some individuals allergic to bananas can also experience a serious immune response, known as anaphylaxis, with a sudden drop in blood pressure. Their respiratory troubles inhibit blood oxygen levels from rising, and they can experience shock. Watch out for symptoms such as increased or reduced pulse rate, light-headedness, and faintness. A study conducted by the Journal of Medical Case Reports reveals such extreme cases of banana allergy even in infants (7). The study further suggests that while introducing solid foods to their babies, parents must be cautious and consider banana as a potential allergen.

12. Constipation

Bananas may cause constipation
Image: Shutterstock

Shocked? Yes, we were shocked too on learning that bananas cause constipation! All along, we have known that bananas aid bowel movements, but the magic lies in how ripe the bananas are. Unripe or green bananas are rich in resistant starches, which can increase the risk of constipation. They even contain heavy doses of tannic acid that has an inhibitory effect on the digestive tract. Tannic acid obstructs the secretion of the gastrointestinal fluid and curbs gastrointestinal motility (8). A ripe banana, on the other hand, can help alleviate constipation. Bananas have been reported as constipation-causing foods (9). Irene Opoku-Acheampong, MPH, RD, LD, says, “Bananas are constipating, so if you have chronic constipation, it’s best to avoid bananas until you’ve passed a few soft bowel movements.”

Bananas are filled with fiber, but they do not contain enough water to make them easy to digest. As a result, your body absorbs less than 10% of the fiber. Fiber helps keep your digestive system healthy and regular. When you don’t have enough fiber in your diet, your bowels become sluggish and constipated.

protip_icon Quick Tip
If your constipation persists, your healthcare provider may prescribe fiber supplements (Citrucel), stool softeners (Docusate), or stimulants (Dulcolax).

13. Gas

Bananas may cause gas problem
Image: Shutterstock

Excess consumption of bananas may result in gas. They contain soluble fiber and fructose, both of which can cause gas. If you suddenly increase your intake of fiber or consume it in huge amounts, it takes a lot of effort for your large intestine to break down the fiber, and it can thus cause gas. Similarly, in the case of fructose, when taken in large amounts, your body can find it difficult to digest it.

14. Risk Of Type 2 Diabetes

Bananas may cause type 2 diabetes
Image: Shutterstock

Bananas fit the ‘medium-level’ glycemic food category, which means that they have the ability to cause a slight spike in your blood sugar levels. Irene says, “Bananas are also carbohydrates, and 1 medium banana counts as 2 servings of carbohydrates. Therefore, bananas should be limited by those who have diabetes.”

Mary Sabat, MS, RD, LD, adds, “Since bananas are high in sugar, people with type 2 diabetes or those who are overweight might have to limit their intake of bananas or combine them with other foods high in protein and/or fat to blunt the insulin response. For most people, however, bananas can be enjoyed like any other fruit in moderation.”

Since the overconsumption of foods with a high glycemic index can increase your risk of developing type 2 diabetes, obesity, and cardiovascular diseases, you should regulate your intake of bananas. This is all the more true in the case of overripe bananas as they have a higher glycemic index as compared to regular bananas (10). However, Barbara Kovalenko, a nutrition consultant says, “Yes, bananas are a natural source of sugar, with an average medium-sized banana containing about 14 grams of sugar. However, this sugar is naturally occurring and is accompanied by fiber, vitamins, and minerals, which can help regulate its impact on blood sugar levels.” In the end, it is recommended to watch out for how many you eat in a day.


Here are some warnings and precautions regarding the consumption of bananas:

  1. In case your kidneys don’t function properly, keep your intake of bananas to a minimum. Too much potassium in your diet can put a lot of strain on your kidneys to remove the excess from your blood. This can be very dangerous.
  1. Since bananas are stored at room temperature, they can get spoiled easily and should be eaten within two days since the day of purchase. At the same time, it is important that you avoid eating underripe bananas.
  1. If you experience cramping, hives, wheezing, and throat irritation each time you eat a banana, you could be allergic to either the bananas or to other fruits containing the same protein.
  1. Irene says, “Banana is an alkaline fruit, which means it has low acid content. People with acid reflux may tolerate this fruit better than citrus fruits, such as oranges and grapefruit.” However, Mary adds, “Banana is a low acid food and may feel good for someone who has acid reflux. However, people with acid reflux should avoid eating bananas right before bedtime, as they may actually cause heartburn since they are lying down on a full stomach.”
  1. In case you want to increase your intake of bananas, do consult your doctor to know the recommended dosage.

Major Interactions

When you are taking medication, you should keep in mind the following banana-drug interactions (11):

1. Beta-Blockers

If you are a heart patient, your doctor may have prescribed you a type of medication called beta-blockers. This medication causes a surge in the level of potassium in the blood. You must, therefore, consume bananas in moderation as they are rich in potassium and can cause a dangerous rise in the potassium levels in your blood.

2. Oxazolidinone Antibacterials

If you are on oxazolidinone antibacterials, you might want to watch your intake of bananas. Bananas contain tyramine that can cause a dangerous increase in your blood pressure when supplemented with oxazolidinone antibacterials. Check with your doctor on the allowed intake.

3. ACE Inhibitors (Angiotensin-Converting Enzyme Inhibitors)

Doctors prescribe these medicines to lower blood pressure or treat heart failure. Like beta-blockers, they increase the amount of potassium in the blood. You must, therefore, avoid overindulging in bananas if you’re on this drug as you may experience irregular heartbeat and palpitations (17).

4. Diuretics

Doctors prescribe diuretics to help the body remove water, sodium, and chloride. Diuretics also help reduce the swelling caused by heart or liver problems. They help treat high blood pressure too. Since some diuretics increase the levels of potassium in the body, you should lower the intake of bananas as they can further increase the level of potassium in your blood, which can be dangerous (18).

Though we have listed down all the cons of eating bananas, do you wonder are bananas good for you? We cannot deny the fact that when eaten in moderation, they certainly are. Unless, of course, you have a health concern that doesn’t allow you to eat them.

The U.S. Department of Agriculture recommends every healthy adult to enjoy two cups of fruit daily (equal to two bananas). Instead of making bananas your staple diet, you should have them alongside other healthy foods. Only then, you can make the best of the benefits of bananas.

Hope we addressed some of the questions you may have had about side effects of banana. Do give us your feedback in the comments section below.

Infographic: 5 Common Side Effects Of Bananas

Bananas are rich in various nutrients, making them ideal for daily consumption by babies and adults alike. However, eating too many bananas may lead to adverse health effects. We have rounded up the 5 common side effects of consuming too many bananas. Check out the infographic below to know more!

5 common side effects of bananas (infographic)

Illustration: StyleCraze Design Team

While bananas are a healthy, tasty fruit, excessive consumption can have some negative effects. The side effects of bananas include migraine, tooth decay, and an increased risk of nerve damage. They may also cause gas or bloating in moderate cases and trigger an anaphylactic shock in severe cases. They may also interfere with certain medications like beta-blockers, diuretics, and ACE inhibitors. But do not get into the dilemma – are bananas bad for you – because most of these are associated with excess consumption. Limiting or avoiding their consumption can help avoid these complications.

Frequently Asked Questions

What happens if you eat 2 bananas a day?

Having two bananas a day falls within the acceptable recommended limit and is safe.

Is having 4 bananas a day too much?

Possibly. Having too many bananas in a day may lead to abdominal cramps, pain, and gas.

What happens if we eat bananas on an empty stomach in the morning?

Anecdotal evidence suggests that having bananas on an empty stomach might lead to abdominal cramps, constipation, and dizziness (15).

Can we drink water after eating a banana?

Anecdotal evidence suggests that having water after consuming bananas may lead to indigestion.

How long does a banana take to digest?

A banana takes about 30 minutes to digest (16).

Key Takeaways

  • Bananas can cause bloating and constipation if you have them in excess quantities.
  • Similar to chocolates, bananas can also create cavities if you do not take extra care in removing the starch particles from your teeth.
  • Bananas are high in calories, so avoid them when aiming for weight loss.
  • Bananas contain a substance called Tyramine that can cause severe migraine headaches.
side effects of bananas

Image: Stable Diffusion/StyleCraze Design Team

Are you eating too many bananas? Find out the serious side effects of eating too many bananas at once in the following video. Take a look!


Articles on StyleCraze are backed by verified information from peer-reviewed and academic research papers, reputed organizations, research institutions, and medical associations to ensure accuracy and relevance. Read our editorial policy to learn more.

  1. The role of tyramine in the aetiology of migraine and related studies on the cerebral and extracerebral circulation
  2. Nutrition And Oral Health
  3. Effects of tryptophan loading on human cognition mood and sleep
  4. Vitamin B6
  5. Hypersensitivity to banana in latex-allergic patients. Identification of two major banana allergens of 33 and 37 kD
  6. Anaphylaxis from bee pollen supplement
  7. A 4-month-old baby boy presenting with anaphylaxis to a banana: a case report
  8. Impact of tannic acid on the gastrointestinal microflora
  9. Diets for Constipation
  10. Influence of ripeness of banana on the blood glucose and insulin response in type 2 diabetic subjects
  11. Food and Drug Interactions
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Reda Elmardi

Reda ElmardiRDN

Reda Elmardi is a registered dietician, certified nutritionist, and certified strength and conditioning specialist trainer. He has more than 10 years of experience and has been an NSCA Certified Strength and Conditioning Specialist Trainer since 2015. He shares sports nutrition tips and gives guidance on exercises, sports, and martial arts through his website. Reda is a Brazilian jiu-jitsu brown belt,...read full bio

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