While watermelon is widely celebrated as a refreshing summer treat packed with vitamins, antioxidants, and hydration benefits, it’s important to remember that this sweet fruit isn’t equally ideal for everyone. In fact, certain individuals should approach watermelon with caution, as its nutritional profile can pose challenges depending on specific health conditions and dietary needs.

1. People with Diabetes
Watermelon is often praised for being low in calories and fat, but it has a high glycemic index (GI). This means that even moderate servings can cause a rapid rise in blood sugar levels. For people living with diabetes or insulin resistance, consuming high-GI foods can make blood sugar management more difficult and may increase the risk of complications over time. To enjoy watermelon more safely, they should consider limiting portion sizes and pairing it with protein or healthy fats (such as a handful of nuts) to slow the absorption of sugar into the bloodstream.

2. Those with Kidney Problems
One of watermelon’s nutritional highlights is its high potassium content. While potassium is essential for heart and muscle function in healthy individuals, people with chronic kidney disease (CKD) or impaired kidney function may struggle to properly filter and excrete excess potassium from their blood. High potassium levels can lead to a dangerous condition called hyperkalemia, which may cause heart rhythm disturbances or muscle weakness. For these individuals, it’s crucial to consult a healthcare provider before including watermelon or other high-potassium foods in their diet.

3. Individuals on a Low-FODMAP Diet
Watermelon contains a type of sugar called fructose, which is classified as a FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols). People who follow a low-FODMAP diet—often recommended for those with irritable bowel syndrome (IBS)—may find that watermelon triggers digestive symptoms such as bloating, excessive gas, abdominal pain, or diarrhea. Although watermelon is naturally sweet and hydrating, these digestive side effects can outweigh the benefits for sensitive individuals.

4. People Prone to Allergies
Although relatively uncommon, watermelon allergies do exist. People with oral allergy syndrome (OAS), especially those allergic to ragweed pollen or other related fruits and vegetables like cucumber, zucchini, or cantaloupe, may experience symptoms when consuming watermelon. Reactions can include itching or tingling of the mouth and throat, swelling of the lips and tongue, and in severe cases, difficulty breathing. It’s essential for anyone experiencing these symptoms to avoid watermelon and seek medical advice.

5. Those Watching Sugar Intake
Even for those without diabetes, watermelon’s natural sweetness means it still contributes to daily sugar intake. A single cup of diced watermelon contains about 9 to 10 grams of sugar. While this may seem moderate, it can add up quickly, especially when eating large portions during hot summer days. Overconsumption can contribute to excessive calorie intake and potential weight gain, or hinder efforts to maintain a low-sugar diet.

The Bottom Line
Watermelon can certainly be part of a balanced diet and offers plenty of health perks: it’s rich in vitamin C, vitamin A (via beta-carotene), lycopene, and provides a hydrating boost. However, it isn’t a perfect fit for everyone. If you belong to one of these groups—or have concerns about how watermelon may affect your health—it’s wise to enjoy it in moderation and consult with a healthcare provider before making it a regular part of your diet.

By understanding your own nutritional needs and listening to your body, you can make informed choices and enjoy summer fruits like watermelon safely and deliciously.