Nobody disputes the severity of this nation’s challenge in dealing with childhood obesity. However, the ham-handed attempt by USDA officials to reverse the curse by scaling back the portions of meat products allowed in the National School Lunch Program — as if eating beef, pork and chicken were the cause of the epidemic of overweight, out-of-shape kids — was decidedly the wrong way to go.

What happened was twofold. There wasn’t any appreciable dent in the obesity statistics, and both kids and parents complained — often bitterly — that the “menu malfunction” left teen-agers and middle-schoolers so hungry they had trouble concentrating on their classwork. School administrators argued that establishing maximum portion sizes on servings of grains and meat was too limiting and made it difficult to plan daily meals.

So a year ago, department officials eliminated the restrictions on meat portions and grain group servings on a temporary basis.

Last week, without admitting to any fault, officials made the rule changes permanent.

Kevin Concannon, USDA undersecretary for food, nutrition and consumer services, said in a statement that the department was delivering on its promise to give school nutritionists “more flexibility” in meal planning.

That’s one way to phrase it. Another would be to acknowledge that obesity is not caused by kids (or adults) eating too much meat. In fact, although sedentary lifestyles tend to exacerbate the problem, it’s not “caused” by a lack of exercise, either.

The origins of the now three decades-old plague of obesity in this country traces directly back to the 1980s, when both public- and private-sector nutrition “experts” launched a campaign cut back on meat, due to its saturated fat and cholesterol content and substitute what amounted to processed starch. It was labeled the new Dietary Guidelines for Americans, and along with the oceans of sweetened soda we increasingly guzzled at every meal occasion imaginable, all those refined calories started piling on the pounds in epidemic fashion.

Meat was never the problem, and in fact, diets containing more protein and less carbs are now increasingly understood to be part of the solution.

‘Eat it or toss it’

Equally as revealing as the pushback to imposing free- and reduced-meat lunches was an online campaign that was conducted at about the same time as USDA’s ill-advised attempts at menu revision. The idea was to get young people engaged with assessing the quality of their school lunches. Called “Fed Up,” the project involved kids posting more than 7,000 photos of pizza, hamburgers, chicken nuggets and nachos served up in cafeterias nationwide.

Students were then asked what they thought about the food typically served for lunch. Although some photos featured salads and freshly made sandwiches, far more looked like warmed-over fast-food.

Participants checked out the photos of each pictured meal and then voted up or down: “Eat it” or “Toss it.” Many meals got a thumbs-up, but about 70 percent of the students said they were to often served unhealthy, unsatisfying meals, and nearly six in 10 reported throwing out all or part of their lunch several times a week.

Personally, I think those data need to be taken with the proverbial grain of salt. What teen- or tween-ager hasn’t found it fashionable to complain about the quality of their school lunch? Heck, it’s fodder for professional late-night comedians, much less the thousands of class clowns who’ve taken a whack at the burgers, pizza and pudding that occupy the center-of-the-tray at lunch hour.

It’s tough enough to prepare institutional quantities of food for a high-priced banquet, as anyone who’s attended corporate or trade show functions can attest. With the budgetary constraints most school districts have to face, it’s asking a lot to expect white tablecloth quality at your local high school or middle school.

But one quality control that should never be violated is making sure that kids have enough to eat — and certainly enough healthy, non-fattening animal products to sustain them during their adolescence.

The “growth years” should be about gaining height, not weight.

The opinions expressed in this commentary are solely those of Dan Murphy, a veteran food-industry journalist and commentator.