Banning soda pop and other sugar-sweetened drinks from schools doesn't seem to reduce how much of them kids drink overall, a U.S. study suggests.

Researchers at the University of Illinois at Chicago wanted to find out whether school bans made a difference in cutting the amount students drank. 

They tracked 6, 900 students at public schools in 40 states. The students filled in questionnaires about their consumption when they were in Grade 5 and then in Grade 8. 

Some of the students attended schools that banned all sugar-sweetened beverages (SSBs) such as pop, sports drinks and high-calorie fruit drinks and others went to schools that banned only pop or had no beverage policy.

About 85 per cent of students reported consuming sugar-sweetened beverages at least once a week and 26 per cent to 33 per cent of students reported daily consumption.

"State policies that ban all SSB in middle schools appear to reduce in-school access and purchasing of SSBs but do not reduce overall consumption," Dr. Daniel Taber, and his colleagues reported in Monday's issue of the Archives of Pediatric and Adolescent Medicine concluded.

In addition, the findings suggested that students who often drank the beverages increased their consumption outside of school when they couldn't buy them in school, the researchers said.

The results could be skewed because youth commonly misreport their daily intake, the team noted.

The study was funded by the Robert Wood Johnson Foundation, and the U.S. National Heart, Lung, and Blood Institute.