WATERMELON.

Watermelon regardless of the darkness of its blue/green skin—can cause diarrhea if consumed in excess. 

The potential for digestive issues is not due to the color of the rind, but rather the nutritional components of the fruit itself. 

Why Watermelon Causes Diarrhea:

• High Fructose Content:Watermelon is high in fructose, a natural sugar that some people struggle to absorb, leading to fermentation in the gut and subsequent diarrhea, gas, and bloating.
• High FODMAP Food: It is considered a high FODMAP food (fermentable short-chain carbohydrates), which often triggers digestive discomfort in people with irritable bowel syndrome (IBS).
• High Water Content: Eating large amounts of water-dense food can temporarily overwhelm your system, causing loose stools.
• Sorbitol: Watermelon contains sorbitol, a sugar compound known to encourage loose stools. 

Tips for Consumption:

• Moderate Intake: For most healthy adults, 1-2 cups per day is considered a safe amount to avoid digestive issues.
• Avoid on Empty Stomach: Eating large amounts of watermelon on an empty stomach may increase the risk of digestive irritation.
• Check for Sensitivity: If you have IBS or a sensitive stomach, you may need to limit your intake to avoid symptoms. 
• If you experience persistent diarrhoea after eating watermelon, it is advisable to reduce your consumption and consult a healthcare provider, as it may indicate an underlying sensitivity to fructose.

Source: Google.