A couple in Xi'an, Shaanxi Province plotted to get their son to stay away from unhealthy pop by secretly adding laxatives to a bottle of cola, before telling the primary school-aged boy not to drink the fizzy stuff because it causes diarrhea.

Whenever the boy asked for soda, the mother told the father to drink the "drugged" bottle. Seeing his father running to and from the toilet was convincing enough for the son to believe the cautionary tale.

"The method really works. My kid no longer asks for carbonated beverages and believes that fresh water is the best choice," said the father.

But after another father in the city also lied to scare his child off Western cuisine, fearing that the non-Chinese foods contain too much fat, experts have warned parents from taking the dishonest approach to educate children.

"It's reasonable for parents to worry about their kids' health, but lying to them is not the answer," said Cai Jun, director of Xi'an University's preschool education research department.