One of my fondest memories from kindergarten was the treat of a couple of graham crackers and chocolate milk served in a waxy paperboard container. In those days, primary school was mostly about helping kids learn how to spend half a day away from mom. Milk was an important bait, luring us into the world of education.

A lot’s changed since then. Kindergarten is now a serious educational venture. Kids make big steps in reading instead of having See Spot Run read to them, and they learn how to write instead of coloring elephants with giant crayons. Chocolate milk too, has changed. It’s now at the center of an enormous policy battle regarding school lunches.

Some school districts have banned flavored milk completely. In Florida, the battle has become white-hot. The State Board of Education campaigned to pull chocolate milk out of lunchrooms, as part of its ongoing effort to eliminate sugared sodas and high-calorie desserts. When the board turned to flavored milk, opposition from the dairy industry flared. Big business was at stake -- in 2010, the state’s four largest school districts spent $13 million on flavored milk, and students downed 49 million half-pints of the chocolate version.

State Agriculture Commissioner Adam Putnam countered the board’s efforts by trying to pull decisions about cafeteria food into his office. But Board of Education member Roberto Martinez fired back, “We have to put the kids first, not the agriculture industry first -- period. End of story.”

So how does taking much-loved chocolate milk out of school cafeterias put kids first? Two words: fat and calories. The standard half-pint serving of low-fat milk has 102 calories, of which 21 come from fat. Chocolate milk has more than twice the calories (226) and almost four times as many calories from fat (78). With childhood obesity reaching epidemic levels, public health groups have pressed school districts to switch to lower-calorie options.

Following on the heels of the wildly popular “Got Milk?” ads, the dairy industry promoted a “Raise your hands for chocolate milk” campaign. In Boulder, Colo., chef Ann Cooper, a self-styled “renegade lunch lady,” says the campaign has more to do with selling milk than promoting nutrition.

In April, Fairfax County, Va., schools reversed their chocolate milk ban after an avalanche of protests from disappointed students -- and concerned nutritionists, who argued that chocolate milk is an important way to get vitamin D and calcium into the diets of nutritionally challenged children. Interestingly, Fairfax’s new chocolate milk is low-fat and contains sucrose instead of high-fructose corn syrup. Some critics of the old chocolate milk say the switch is healthier because sucrose is less heavily processed. Others say that sugar is sugar and it doesn’t make much difference how it comes into the diet. The Corn Refiners Association shares that opinion -- and a concern that it not lose the big chocolate milk market.

The feds have found themselves squarely in the middle of this intense battle. The U.S. Department of Agriculture’s (USDA) Center for Nutrition Policy and Promotion, along with the Department of Health and Human Services, reinvented the food pyramid to help Americans make healthier choices, and especially to help reduce the fat and calories in the diets of youngsters. Meanwhile, the National Milk Processor Board, which created the “Got Milk?” campaign, works under the USDA’s umbrella as part of its mission to promote dairy products. The department’s National School Lunch Program provides subsidized meals and snacks for less-affluent children. It calls for schools to serve milk, and chocolate is OK.

Is it the USDA’s policy to promote good nutrition, low-fat milk, chocolate milk or milk production in general, regardless of flavor? One way or another, the answer is yes, to all four. Then there’s first lady Michelle Obama’s campaign for child nutrition, and Rep. Michele Bachmann’s charge that the first lady is trying to roll out a “nanny state.” Bachmann castigated the nutrition campaign in telling talk radio host and Fox News contributor Laura Ingraham that “For them, government is the answer to every problem.”

One blogger at the San Francisco Chronicle simply told other readers, “You couldn’t get me to drink school milk as a child. If it was chocolate, I’m sure it would have been different! It’s like an adult at Starbucks ... even kids need a little vice!”

But this little vice, if that’s what it is, has become a very big battle. Fairfax’s Penny McConnell, who directs the district’s food and nutrition services, says that before the district reversed its decision she received 10 to 20 e-mails a day contending that students liked the drink and it supplied essential nutrients to help growing kids grow strong bones. “It was a lot of pressure.”

Since 1946, milk has been a cornerstone of the federal school lunch program. Little did its sponsors back in the Truman administration realize that their plan to bring better nutrition to the nation’s children would erupt into such a deep moral, scientific, economic and political battle, involving everyone from renegade lunch ladies to first ladies. It makes me long for a few sips of soothing snacks and a nap on the blanket I used to store in my kindergarten cubby.