WEDNESDAY, Jan. 25 (HealthDay News) -- First Lady Michelle Obama and Agriculture Secretary Tom Vilsack unveiled on Wednesday new standards for school meals -- the first revisions in more than 15 years. The goal: To provide healthier meals and better nutrition for the nearly 32 million children who take part in school meal programs.

The new standards include offering fruits and vegetables every day, increasing whole grain-rich foods, serving only fat-free or low-fat milk, limiting calories based on children's ages, and reducing the amounts of saturated fat, trans fats and sodium, according to a news release from the U.S. Department of Agriculture.

Mrs. Obama and Vilsack, who were joined by celebrity chef Rachael Ray, made the announcement at an elementary school in Alexandria, Va.

"As parents, we try to prepare decent meals, limit how much junk food our kids eat, and ensure they have a reasonably balanced diet," Mrs. Obama said in a news release. "And when we're putting in all that effort, the last thing we want is for our hard work to be undone each day in the school cafeteria. When we send our kids to school, we expect that they won't be eating the kind of fatty, salty, sugary foods that we try to keep them from eating at home."

In the same statement, Vilsack said, "Improving the quality of the school meals is a critical step in building a healthy future for our kids."

Dr. David Katz, director of the Prevention Research Center at Yale University School of Medicine, said that "these changes to school food standards are welcome, commendable and unquestionably helpful in efforts to combat childhood obesity and all of the metabolic mayhem that follows in its wake."

Still, Katz doesn't think the changes go far enough.

And they aren't as complete as the Obama administration had wanted, according to the Associated Press.

Last year, Congress blocked some of the agriculture department's planned revisions, including cutting down how often french fries and pizza could be served, the news agency said.

In November, Congress passed a bill requiring the agriculture department to continue to count tomato paste on pizzas as a vegetable, the AP reported.

"Making healthier pizza is a great idea. However, it is unfortunate and rather ridiculous that Congress still thinks tomato paste is a vegetable," said dietitian Samantha Heller, clinical nutrition coordinator at the Center for Cancer Care at Griffin Hospital in Derby, Conn.

Congress also refused to allow the USDA to limit servings of potatoes. Those congressional directions must be incorporated into the final rule, the AP reported.

The news service said that potato growers, companies that make frozen pizzas for schools and others in the food industry lobbied for the changes made by Congress, and that conservatives said the government shouldn't be telling children what to eat.

Some school districts objected to some of the requirements, saying they went too far and would cost too much, the AP said.

Katz said, "It is unacceptable that food industry elements lobbied Congress successfully for changes in nutrition standards that placed profits ahead of children's health.

"The argument that we cannot afford to do even better is spurious, because it leaves us needing to afford the treatment of type 2 diabetes in children. It leaves us needing to pay for bariatric surgery in adolescents," he added.

Still, the changes signal some progress, Katz said. "We should not expect it to change childhood obesity rates. School lunch was never the cause of epidemic obesity, and improving it will not be the cure. But school lunch has long been part of the problem and these improved standards will help make it one part of a comprehensive solution, now long overdue," he said.

Heller rejected the argument that children will not eat healthier foods.

"When given the time, exposure and encouragement as well as altering environmental influences, kids will eat healthy foods when available," she said. "Just putting fresh fruit by the cafeteria check-out in schools increases consumption by schoolchildren considerably. Making fresh, healthy foods delicious and explaining to kids how and why good nutrition is critical for them to do well in their favorite activities such as sports, art or science, will also boost consumption," Heller said.

"Food companies, lobbyists, and members of Congress would do well to step up to the plate and start setting good examples of healthy eating and lifestyles," Heller added.

The new rule is based on recommendations from a panel of experts from the Institute of Medicine and also updated changes from the 2010 Dietary Guidelines for Americans.

More information

For more information on healthy eating, visit the U.S. Department of Agriculture.