My wife and I are on a health kick. We go to the local gym. We eat fish, lean meat and vegetables. I resist cheese, a lifelong favorite. I astonish our children by consuming only one milkshake a week.

Still, we understand the potential for backsliding. At our age, people live for the present and worry less about the future. We are like high school students who gravitate toward fast food because the consequences of too much sugar, salt and fat don’t interest them.

I noticed, then, when the many optimistic stories about the Agriculture Department’s new school meal nutrition standards — based on the assumption that teenagers will happily pile more fruits, veggies and whole grains on their plates — were undercut by a visit to school lunch lines by Teresa Watanabe of the Los Angeles Times.

She found trouble with the L.A. school menus that were changed last year to more healthy choices — black bean burgers, tostada salad, fresh pears — in line with the new federal guidelines.

“Principals report massive waste, with unopened milk cartons and uneaten entrees being thrown away,” she wrote in December. “At many campuses, an underground market for chips, candy, fast-food burgers and other taboo fare is thriving.”

Educators have complained for decades about social and political leaders demanding special school services that — while well-intended and popular — are unlikely to improve academic achievement.

Vocational classes that prepared low-income students for dead-end jobs were strongly supported by school boards for many years. Bitter battles among parents and ideologues over how to present American history turned textbooks into mush. Cafeteria menus were loaded with milk, corn, beef and processed foods, meaning more profits for agribusiness but less nutrition.

From that perspective, healthier food is a nice change. But it is vulnerable to powerful forces that often affect schools but are rarely mentioned, particularly in the upbeat stories hailing the new school food standards.

Washington area school officials have welcomed the move away from starch and sweets.

The D.C. Council passed the Healthy Schools Act in 2010. Its author, council member Mary M. Cheh (D-Ward 3) , said the city’s schools served 2.5 million more meals after the law was passed than the year before, and reduced costs by $3 million.

“This year, thanks to new menus and a salad bar, as many students buy lunch at Wilson [High School] in a single day as they did in a typical week in previous years,” she told me.

Nationally, school lunch experts say schools are changing eating habits by putting fruit and vegetables in easy-to-reach spots near the cash register and making desserts, soft drinks and chips harder to find. Start in preschool telling kids how a salad can be a fine lunch and you make a big difference, experts say.

Rarely mentioned in these visionary articles are school district budget officers and students.

The financial types point out that some of the fresh food programs cost more than the previously dominant processed food. Those who attend schools, particularly high schools, are even more troublesome. They have to eat the new stuff.

In Los Angeles, the school system backtracked after an anti-vegetable revolt. Hamburgers returned as daily fare. The beef jambalaya, vegetable curry and black-eyed pea salads disappeared.

Pizza came back, although with a whole wheat crust, low-fat cheese and low-sodium sauce that I wouldn’t eat. It will be a difficult sale to many teens.

In my freezer sits chocolate chip and chocolate fudge brownie ice cream. I haven’t touched it in weeks, but how long can I keep that up?

Healthy food is good, but adolescents are as erratic as I am. This latest attempt to put schools at the front of a social movement is at risk because the young recruits leave the building every afternoon and have other dietary choices.

For previous columns by Jay Mathews, go to