4 Side Effects Of Watermelon: How Much Is Too Much?

Watermelon has a great reputation. You’re always told to eat a lot of it – and you sure won’t object! This refreshing fruit is a savior on a hot summer day as it t can hydrate your body, thanks to its 92% water content.

But like everything else, watermelons need to be eaten in moderation too. Eating too much can have these 4 side effects.


1. Diarrhea

Watermelon can cause diarrhea

It’s no secret that watermelon will boost your hydration status. But it will also up your risk for diarrhea if you have too much. It is more likely if you’re taking medications like antibiotics and antacids, which mess with your digestive system.


A common cause of diarrhea from watermelon is the lycopene. This pigmented antioxidant gives watermelon its pretty red hue. However, eating a lot of it will cause watery stools. And since watermelon has 40% more lycopene than raw tomatoes, it pays to be careful.

If you already eat lots of red fruits and veggies, go easy on the watermelon. One slice has 14.7 mg of lycopene, and the recommended amount is about 30 mg. Therefore, eating 2 – maybe 3 – slices each day should be fine.1


2. Irregular Heartbeat

Watermelon can affect your heartbeat

Watermelon is rich in potassium, a mineral that controls your heart rate. One wedge has roughly 320 mg of potassium. And while this is far from the recommended daily intake of 4,700 mg, it can accumulate if you eat too many.


Usually, the kidney excretes extra potassium. But if you already have kidney problems, hyperkalemia may develop and cause irregular heart beats and palpitations. Overeating watermelon is also bad news if you eat a lot of bananas, oranges, and tomatoes. These fruits are already very high in potassium.

This side effect of watermelon can also crop up if you eat a high-protein diet. Many high-protein foods like fish and eggs are also high in potassium.2


3. High Glucose Level

watermelon effect on blood sugar

If you’re diabetic, you might be wondering about the effect watermelon has on blood sugar. It does have a high glycemic index of 72, but its glycemic load is only 4.3 This means that a serving won’t do any harm. But if you overdo it? You’ll have a spike in glucose levels, which is never good news. So diabetics should always eat watermelon in moderation, like any other fruit that they are allowed to eat.


4. Liver Inflammation

Alcoholics should avoid eating too much watermelon

Alcoholics should avoid eating too much watermelon. High levels of lycopene will interact with alcohol, causing liver inflammation. This effect can be dangerous, especially since the liver is already stressed out.4


Oxidative stress in the liver is also more likely when alcohol and lycopene mix.5

As with all foods, portion size is key. You won’t have side effects from watermelon or watermelon juice if you eat it in moderation. Keep your diet diverse and you’ll be just fine.