CHAPEL HILL — How long will you live? I can expect to reach age 80 or so, according to government estimates. But many members of my children's generation may not be so lucky.

A recent study in the New England Journal of Medicine found that today's heaviest children are more than twice as likely as those at healthy body weights to die prematurely - before the age of 55.

That was the U.S. life expectancy nearly a century ago. Then, people often died young from untreatable conditions like tuberculosis. But today's young people are endangered by problems we can prevent - childhood obesity and associated health conditions such as type 2 diabetes and hypertension.

As a mother and a nutrition researcher, I'm frustrated by how widespread these preventable problems have become. That's why I'm delighted by Michelle Obama's initiative to fight childhood obesity. As the first lady has recognized, one key step is to provide children with more healthful school lunches, including plenty of fruits and vegetables.

Congress should keep that fact in mind over the coming weeks as lawmakers revise the Child Nutrition Reauthorization Act, which helps determine what foods are served in school lunchrooms across the country. One proposal just introduced by Rep. Jared Polis, the Healthy School Meals Act of 2010, would go a long way toward making sure students have healthful options.

Here's one thing we know: Kids don't need more cheeseburgers, hot dogs or pepperoni pizzas.

These high-fat, cholesterol-laden foods have become all too common in many school lunchrooms. More than 70 percent of schools serve too much high-fat food to comply with federal guidelines, according to the federal government's School Nutrition Dietary Assessment Study.

Meat-heavy menus, at home, as well as at school, have helped supersize the prevalence of type 2 diabetes, heart disease, cancer and other chronic diseases. One in three children born in 2000 will develop diabetes at some point in life. The percentage of overweight and obese children is now at or above 30 percent in 30 states, according to a recent report from the Trust for America's Health.

School food service directors want to serve healthy food, but they're coping with tight budgets and uncertain access to nutritious options. That's where Congress comes in. The Healthy School Meals Act would help schools serve more fruits, vegetables, whole grains and low-fat vegetarian meals.

The American Public Health Association and the American Medical Association have voiced their support for vegetarian school lunch options. It's not hard to see why when you take a hard look at the meat-based options on many school lunch menus.

Take a standard hamburger. Three ounces of cooked ground beef typically have 13 to16 grams of fat, a big dose of cholesterol and absolutely no fiber. A veggie burger, on the other hand, can have as little as 1 gram of fat, zero cholesterol and plenty of protein and fiber. Even if a student chooses vegetarian meal options twice a week, he or she is taking a big step toward cutting fat intake and improving overall health.

I have great expectations that the momentum building around ending childhood obesity will reverse the grim trends threatening our children's future. But for that to happen, Congress must help schools serve more fruits, vegetables and low-fat vegetarian meals. That critical step would go a long way to ensuring that our children will have the healthy lives - and healthy lifespans - we all want for them.

Brie Turner-McGrievy is a postdoctoral fellow in nutrition at the UNC-Chapel Hill Interdisciplinary Obesity Center.