There is no scientific evidence to support that one should not have water after having fruits such as watermelon.
However, according to Ayurveda, drinking water after eating watermelon can disturb the normal functioning of the digestive system.
Ayurveda takes this position because watermelon is 90+% water.
So, drinking water after something which is almost entirely water can cause heaviness in the stomach.
Now, along with water, the watermelons also contain sugar and fibre.
Though present in a small amount in the watermelon, this fibre is rich in prebiotics (it is different from probiotics).
Prebiotics is the kind of food that humans can’t digest, but that feeds good bacteria in the gut.
Water can scatter the prebiotics making their access difficult to the bacteria, thereby affecting the digestive system.
The prebiotics argument is weak because there are many foods that contain prebiotics (e.g. garlic, onion, chickpeas, oats, etc.)
So, if we avoid drinking water after the watermelon, we should avoid water after these foods as well.
The second argument is that fibre smoothens bowel movement, and excess water can speed up the process, causing loose motions/diarrhoea.
While this may be true in some cases, our digestive system is well-equipped to adapt to different food consistencies and should be able to handle “liquidy food” topped up with an extra dash of water.
So, while drinking water after watermelon may be illogical and discomforting, it doesn’t seem entirely unhealthy or dangerous.
