At the center of our national school playground lies a statistical seesaw. On one end sit children who are still managing to maintain a healthy weight. On the other: the growing number of youngsters whose excess pounds put them at increased risk of type 2 diabetes, asthma and hypertension – as well as bullying and social isolation.

But this balancing act is about to reach a tipping point, as many concerned parents and teachers know all too well. In 2010, nearly half the children in North America will be overweight or obese, according to a recent report in the International Journal of Pediatric Obesity.

Alarming statistics like these are prompting legislative action. Connecticut lawmakers just voted to prohibit public schools from selling sodas and sugary sports drinks. And Sen. Tom Harkin, D-Iowa, recently introduced the Child Nutrition Promotion and School Lunch Protection Act, which would require higher nutritional standards for food products sold in school vending machines and snack bars.

The soda industry has seen the writing on the wall. In a deal recently announced by the William J. Clinton Foundation, the nation’s largest beverage distributors agreed gradually to stop selling non-diet sodas to most public schools.

That’s a good first step in the battle against childhood obesity. But the soda debate also offers a larger hope. After all, soft drink and candy companies are hardly the only ones to blame for childhood obesity.

Congress, prodded by the debate over Harkin’s proposal, might finally take a hard look at the ways in which the federal government itself – through misguided agricultural and nutrition policies – makes food served in the school lunch line a nutritional hazard for our nation’s young people.

Menus in most school lunch programs are too high in artery-clogging fats and cholesterol and too low in healthy fruits, vegetables, whole grains and legumes. One key reason: The National School Lunch Program and the School Breakfast Program, which are run by the U.S. Department of Agriculture, push schools to make high-fat meat products the centerpiece of every meal.

The good news about these two programs, which provide financial assistance and commodities to schools across the country, is that they allow millions of needy American students to receive a free or reduced-price lunch or breakfast every day. Unfortunately, however, many of these meals are not healthy.

The USDA buys up millions of pounds of surplus beef, pork and other high-fat meat products to distribute to schools, but it does not subsidize meat alternatives. That poses a tough dilemma for school food service workers, who often work within tight budgets. It can cost a school district more than twice as much to provide a high-fiber, low-fat veggie burger instead of a high-fat, fiber-free hamburger.

As a result, the government’s own School Nutrition Dietary Assessment Study has found that an astonishing 80 percent of schools serve too much fatty food in the lunch line to comply with federal guidelines.

Changing federal policies to ensure that children have access to healthier food at school isn’t easy. Even modest reforms often face resistance from powerful industries with a huge financial stake in business as usual.

The Connecticut soda restrictions, for instance, drew opposition from predictable foes. A few years ago, soda companies were trying to lock every school in America into exclusive contracts that kicked all competing soft drinks off campus. But suddenly, many of those same corporations rediscovered the principle of freedom of choice and blasted efforts to keep soda machines off school grounds.

More profound improvements would provoke even more protests. Imagine how the pork industry would squeal, for example, if it could no longer sell its surplus high-fat products to the USDA for redistribution to the nation’s schoolchildren.

But our legislators need to find the political will to make tough decisions. More money is needed to expand healthful nutritional initiatives like the USDA’s highly successful Fruit and Vegetable Pilot Program. And less money is needed elsewhere: The government must stop forking over tax dollars to agribusiness to buy surplus meat and high-fat dairy products that kids don’t need.

The alternative is a future in which obesity rates tip out of balance – and the next generation finds itself weighed down under a terrible burden of excess pounds and chronic disease.

– Dulcie Ward is a nutritionist with the Physicians Committee for Responsible Medicine, 5100 Wisconsin Avenue NW, Suite 400, Washington, D.C. 20016; www.pcrm.org.