If you randomize overweight adolescents into one of two groups

in which they're either advised to drink eight cups of water a day or not,

what happens after six months?

The first question you always have to ask with interventional studies is,

did the study participants actually comply?

Both groups started out drinking around two cups a day, and so the study was designed

to see if there's a weight loss benefit of consuming six extra cups of water.

Unfortunately, the difference in water intake between the groups came out

to be less than a cup and a half, which wasn't enough to show any benefit. Only one or two

teens in the water group reportedly reached the target intake. To improve compliance, another

set of researchers asked kids to check their pee.

The group of overweight 9 to 12-year-olds randomized to the water intervention were told

to increase their water intake to the point their urine became straw-colored, a pale yellow.

Still, not every kid complied, but those who did lost significantly more weight.

Inspired by these small pilot studies and early successes with school-based interventions in Europe,

researchers launched the most ambitious study yet, involving more than a million students in New York City public schools.

They compared obesity rates and weight gain in schools that implemented cooled, fast, filtered water dispensers compared to controlled schools that hadn't,

and the increased water access appeared to translate into less weight gain and lower rates

of overweight kids. In the very least, we should stop prohibiting water from classrooms.

The accompanying editorial in the AMA's Pediatrics Journal was entitled,

The Power of a Simple Intervention to Improve Student Health Just Add Water.

Couldn't that result just be explained by decreased consumption of soft drinks?

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