A coalition fighting for school choice — in milk — is attempting to put chocolate milk back on the table in school cafeterias after milk consumption among city schoolchildren dropped this year.

Public school students are drinking 10% less milk than a year ago, which members of the coalition, Advocates for School Milk Choice, blame on a city policy to reduce offerings of flavored milk starting last year. In what was called an effort to reduce obesity rates, the city has phased out whole milk and chocolate milk — the no-fat type — is now served only on Fridays.

The milk choice advocates, who are testifying in a City Council hearing today called by Council Member William de Blasio, warn that calcium deficiencies could lead to just as many problems as obesity. They are pushing the city to reinstate flavored skim milk every day.

“This is an emotionally charged issue. I’m concerned with childhood obesity, too,” the chairman of Advocates for School Milk Choice, Keith Ayoob, an associate professor of pediatrics at Albert Einstein College of Medicine who also works at a children’s clinic, said. “But we’ve got a calcium crisis in this country that’s worse than the diabetes crisis. I don’t think of just obesity, I think of the whole child.”

Nationally, Mr. Ayoob says, seven out of 10 younger children and nine of 10 teenage girls don’t get enough calcium. The organization, formed by a group of concerned parents and nutritionists, argue that the benefits of drinking milk — which they say children are more prone to do if it tastes like chocolate, vanilla, or strawberry — outweigh the calories from sugar that children get from the added flavoring.

Mr. de Blasio, who said he took up the issue partly because of his personal struggles to convince his own children to drink enough milk, says nutrition is not the only reason he and other milk choice advocates are upset. They are also concerned that the decision to alter the milk options was made with little parent input, something they’re hoping the hearing today will change.

“Milk is a backbone of nutrition, and to make a change that would inherently mean children would drink less milk … there needs to be a discussion with parents,” he said.

The change in milk policy is part of a larger Bloomberg administration effort over the past several years to improve nutrition in schools. A Department of Education spokeswoman, Marge Feinberg, said she was optimistic that milk consumption would rise again, noting that a similar situation occurred when white bread was phased out of school cafeterias.

“When we replaced white bread with wheat bread, consumption went down,” she said. “But then it bounced back up.”