Children who don't have greens in their diet have 13 times more chances to get constipation, according to a new study.

The research further discovered that drinking less than two glasses of water per day raises the risk to a great extent.

Constipation is a very painful condition when the movement of bowel become infrequent or hard to pass and can result in more serious bowel obstructions, as reported by the Journal of Clinical Nursing.

Moon Fai Chan and Yuk Ling Chan hailing from the National University of Singapore and Hong Kong Polytechnic University respectively observed the dietary practices of 383 primary school children living in Hong Kong.

The group of researchers discovered that 7% of the 8-10 year old kids suffered from functional constipation, which is constipation not having any physical or psychological cause.

Children who disliked fruits or vegetables had 13 times more the possibility to struggle in the toilets. Meanwhile children who did not drink ample water were eight times more likely to struggle.

Chan added that the various studies have suggested that functional constipation among children is becoming worse with time.

The estimation is that functional constipation makes up for 95% of the constipation cases affecting children.