Can Watermelon Cause Diarrhea? Watermelon’s Side Effects You May Not Know In 2024

Giovanna Rosario, RDN
Dr. Michael DiLeo, MD
Among summer fruits, watermelon is a fun treat for 2024. It is hydrating and sweet, but can you eat too much? Can watermelon cause diarrhea?
can watermelon cause diarrhea
Watermelon is an excellent hydrating fruit. Photo: Shutterstock

Watermelon is a commonly available fruit from the gourd family. It is a popular low-calorie refreshing treat for the summer. Many of us enjoy it during warm months to hydrate ourselves. Watermelon is also a versatile fruit that can be used in cooking, consumed on its own, or in juice.

Fruits are a source of a variety of sugars and fiber. In excess, some fruits may cause gastrointestinal symptoms. Some of us who try to enjoy watermelon may suffer from an unexpected side effect. If you have a sensible stomach, you may ask yourself, can consuming watermelon cause diarrhea, too?

Can Watermelon Cause Diarrhea?

Yes, watermelon may cause diarrhea for some individuals. For example, people with irritable bowel syndrome may need to avoid consuming watermelon since it’s high in fructans, polyols, and excess free fructose. In addition, if contaminated watermelon is consumed, it may cause gastrointestinal symptoms like stomach pain and diarrhea, sometimes referred to as food poisoning. Fruits like watermelon are high in moisture and low in acidity, a good ground for bacterial growth.

Watermelon Nutrition Stats

Watermelon is a fruit comprised of mainly water. It is low in fat and carbohydrates, making it an excellent snack or dessert. You can eat it raw, grilled, on a salad, in a smoothie, or just enjoy a glass of watermelon juice. 

One cup of diced watermelon[1] offers

  • 46 calories
  • 11.5 grams of carbohydrates
  • 1 gram of protein
  • 9 grams of sugar
  • 1 gram of dietary fiber
  • 1.52 milligrams of sodium
  • 170 milligrams of potassium
  • 42 micrograms of vitamin A

It also contains many other minerals like zinc and calcium. It has vitamins like folate and vitamin C. Watermelon is over 90% water. This refreshing fruit can be used as a source of fluids. It can also be a sensible snack for people with diabetes due to its lower carb content.

Watermelon is also a source of lycopene,[2] which has potential for cancer prevention. This carotenoid[3] is a strong antioxidant that is associated with the prevention of prostate cancer[4] and coronary artery disease. Watermelon intake, along with other lycopene-rich foods, may improve blood pressure and arterial stiffness, decreasing cardiovascular risk.    

The Dietary Guidelines for Americans[5] recommend eating 1.5 to 2.5 cups of fruits daily for a decrease in risk of all-cause mortality, obesity, type 2 diabetes, and cancer.

A study using data from the National Health and Nutrition Examination Survey suggested that people who ate watermelon had better diet quality.[6] This could be related to the nutrient density of watermelon and its antioxidants. Watermelon lovers can celebrate all these good stats.

Does Eating Too Much Watermelon Cause Diarrhea?

Eating large quantities of watermelon may cause diarrhea for some individuals. This effect may be more noticeable if you suffer from irritable bowel syndrome. With IBS, you may be more sensitive to particular carbohydrates, causing negative gastrointestinal symptoms. More than one serving of watermelon may trigger symptoms like nausea, abdominal cramps, and diarrhea. 

Excessive consumption of foods high in fiber, sugar, or fat may also cause diarrhea for some people. Malabsorption disorders, in which a person cannot digest some components of foods, may also cause diarrhea.  

Why Does Eating Too Much Watermelon Cause Diarrhea?

Watermelon is high in high in fructans, polyols, and excess free fructose, which may cause gastrointestinal distress for people with IBS. Your doctor may have recommended you follow a low FODMAP diet[7] to manage your IBS. 

Watermelon is considered to be high in FODMAPs,[8] which stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. These are short-chain carbohydrates that are poorly digested in our intestines. FODMAPs ferment in the colon and draw water into the intestines. For people with functional gastrointestinal diseases like IBS, these become problematic, causing issues like pain, gas, bloating, constipation, diarrhea, along other symptoms. 

Watermelon contains three types of short-chain carbohydrates in larger amounts. This makes it problematic for a person sensible or intolerant to these in watermelon. The best way to determine if watermelon or any other food is the cause of your diarrhea is to avoid it for some time and then attempt to incorporate it into your diet. 

Can cantaloupe cause diarrhea, too? If you have IBS, cantaloupe is not considered a high FODMAP food. This means you eat melons like cantaloupe or honeydew as an alternative to watermelon. These can also be a source of energizing carbohydrates, water, and fiber. 

Other Side Effects Of Watermelon

Like all foods, excessive consumption of watermelon may have some other adverse effects on the body. Eating watermelon without hygienic food handling may also cause some uncomfortable symptoms. 

Affect Your Blood Sugar Levels

A common effect fruits have is to increase blood glucose levels. Fruits offer carbohydrates, which are a source of energy for our bodies but may increase your blood sugar levels. This is inadvisable for people with diabetes. Instead, consume a single serving of melon at a time, approximately one cup. 

Food Poisoning With Contaminated Melon

Consuming melon raw can lead to food poisoning[9] if not managed correctly. Watermelon grows on the ground, and when cut, it may become contaminated with bacteria, e.g., Salmonella. The pulp’s moist environment allows bacteria to grow quickly. There are ways to prevent this from happening by practicing safe food handling. 

Some food safety[10] tips to follow when eating fresh fruits and vegetables:

  •  Make sure to use clean utensils and wash your hands before handling fruit. 
  • Wash the exterior of your food with running water.
  • Cut fruits and vegetables that are to be consumed raw, separate from raw animal meat. 
  • Remove all bruised or damaged sections. 
  • Refrigerate cut foods within 2 hours of cutting them to decrease the bacterial growth rate. 

Do you still wonder why watermelon gives me diarrhea? There could be multiple causes. You may not tolerate this fruit, you ate too much of it at one time, or you ate contaminated watermelon. The best way to know is to monitor if it happens every time you eat it or if it happens only once, then it is resolved. That can be a starting guide to figure out if you should avoid it or consume it in moderation. 

Does all this mean that watermelon is bad for you? No. It is nutrient-packed and hydrating. Keep in mind that if you consume a large serving in one sitting, you will most likely experience proverbial watermelon poop or the runs. If you know this fruit is not tolerated, avoid it altogether, eating alternatives. 

Diarrhea Treatments

Diarrhea[11] is defined as watery loose stools three or more times daily. Although common, diarrhea can lead to dehydration and electrolyte imbalances, a health risk. Treatments for diarrhea may include some dietary interventions, food restrictions, or pharmacological treatment. Which diarrhea treatment is best depends on the cause.  

 Some common treatments[12] you can do at home:

  • Limit consuming foods high in sugar, fructose, high fructose corn syrup, lactose, and the sugar alcohol sorbitol. Avoid juices with added sugar and milk. 
  • Hydrate with water, natural juices in small quantities, salty broths, sports drinks, and rehydration drinks. 
  • Avoid caffeinated beverages. Choose decaf. 
  • Avoid spicy foods, which can worsen diarrhea.

If you suffer diarrhea from IBS, work with a Registered Dietitian to implement a low FODMAP diet to improve symptoms. The dietitian will work with you on an elimination diet[13] and balance your diet to avoid nutrient deficiencies.

You may also discuss with your medical provider the use of probiotics for diarrhea. Many probiotic supplements may meet your needs. Probiotics[14] also work to ease infectious diarrhea or diarrhea after antibiotics. Probiotics also help maintain the right balance of bacteria. 

Eating some probiotic foods like yogurt, kefir, kombucha, and kimchi after your diarrhea resolves can prevent recurrence. Fermented foods containing healthy strains of bacteria can help you maintain your gut health, preventing diarrhea and constipation.

Even when food does not cause diarrhea, include some healthy fruit after your bowel movements are regulated. This practice maintains digestive health. 

The Bottom Line

Eating watermelon can cause diarrhea for some individuals, especially those with IBS. While you may be able to consume a small amount or wedge of watermelon without issues, it may be wise to limit portions. Lastly, do not forget to practice safe food handling to prevent any food poisoning and have a happy eating experience.

Frequently Asked Questions

How much watermelon is too much?

It will depend on your tolerance. A regular portion of watermelon is a small wedge or around a cup of diced fruit. Some individuals may not be able to exceed this amount.

Is watermelon good for you when you have diarrhea?

If you have diarrhea and watermelon is not a known trigger, it may be hydrating. Remember that it still contains polyols, which is a sugar alcohol and needs to be limited.

Is watermelon good for IBS diarrhea?

Not if it is one of your triggers. It is a high-FODMAP food that may cause or worsen IBS diarrhea.

What fruit stops diarrhea?

There are really no foods that will stop diarrhea. On the other hand, some fruits may be gentler on your bowels. Fruits like bananas, applesauce, and berries tend to be gentle on the stomach.

Resources

  1. Usda.gov. (2023). FoodData Central. [online] Available at: https://fdc.nal.usda.gov/fdc-app.html#/food-details/167765/nutrients
  2. Medlineplus.gov. (2020). Lycopene: MedlinePlus Supplements. [online] Available at: https://medlineplus.gov/druginfo/natural/554.html
  3. Bohn, T., Bonet, M.L., Borel, P., Keijer, J., Landrier, J.-F., Milisav, I., Ribot, J., Riso, P., Winklhofer-Roob, B., Sharoni, Y., Corte-Real, J., Helden, Y. van, Loizzo, M.R., Poljšak, B., Porrini, M., Roob, J., Trebše, P., Tundis, R., Wawrzyniak, A. and Rühl, R. (2021). Mechanistic aspects of carotenoid health benefits – where are we now? Nutrition Research Reviews, [online] 34(2), pp.276–302. doi:https://doi.org/10.1017/S0954422421000147.
  4. Chen, P., Zhang, W., Wang, X., Zhao, K., Devendra Singh Negi, Li, Z., Qi, M., Wang, X. and Zhang, X. (2015). Lycopene and Risk of Prostate Cancer. Medicine, [online] 94(33), pp.e1260–e1260. doi:https://doi.org/10.1097/md.0000000000001260.
  5. USDA (2020). Dietary Guidelines for Americans 2020 -2025 Make Every Bite Count With the Dietary Guidelines. [online] Dietary Guidelines for Americans. USDA. Available at: https://www.dietaryguidelines.gov/sites/default/files/2021-03/Dietary_Guidelines_for_Americans-2020-2025.pdf.
  6. Fulgoni, K. and Fulgoni, V.L. (2022). Watermelon Intake Is Associated with Increased Nutrient Intake and Higher Diet Quality in Adults and Children, NHANES 2003–2018. Nutrients, [online] 14(22), pp.4883–4883. doi:https://doi.org/10.3390/nu14224883.
  7. and, D. (2023). Eating, Diet, & Nutrition for Irritable Bowel Syndrome. [online] National Institute of Diabetes and Digestive and Kidney Diseases. Available at: https://www.niddk.nih.gov/health-information/digestive-diseases/irritable-bowel-syndrome/eating-diet-nutrition
  8. Oligosaccharides, F. (n.d.). Low FODMAP Diet FODMAP? What does that stand for? [online] Available at: https://med.virginia.edu/ginutrition/wp-content/uploads/sites/199/2018/05/Low_FODMAP_Diet_12.16.pdf.
  9. Walsh, K.A., Bennett, S., Mahovic, M.J. and L. Hannah Gould (2014). Outbreaks Associated with Cantaloupe, Watermelon, and Honeydew in the United States, 1973–2011. Foodborne Pathogens and Disease, [online] 11(12), pp.945–952. doi:https://doi.org/10.1089/fpd.2014.1812.
  10. CDC (2023). Fruit and Vegetable Safety. [online] Centers for Disease Control and Prevention. Available at: https://www.cdc.gov/foodsafety/communication/steps-healthy-fruits-veggies.html
  11. and, D. (2023). Definition & Facts for Diarrhea. [online] National Institute of Diabetes and Digestive and Kidney Diseases. Available at: https://www.niddk.nih.gov/health-information/digestive-diseases/diarrhea/definition-facts
  12. Medlineplus.gov. (2016). Diarrhea. [online] Available at: https://medlineplus.gov/diarrhea.html
  13. Chey, W.D. (2019). Elimination Diets for Irritable Bowel Syndrome. The American Journal of Gastroenterology, 114(2), pp.201–203. doi:https://doi.org/10.14309/ajg.0000000000000099.
  14. José, J. (2017). Revisión del papel de los probióticos en la patología gastrointestinal del adulto. Gastroenterología y Hepatología, [online] 40(6), pp.417–429. doi:https://doi.org/10.1016/j.gastrohep.2016.12.003.‌

More from Digestion