Outside of Michelin-starred restaurants, few menus are as hotly debated as public school lunches.
In the US, school lunches have to adhere to nutrition standards mandated by Congress. These were updated in 2010 for the first time since the 1940s, and again in 2015—each time under intense pressure from agriculture industry groups that pushed for menus giving a starring role to meat, dairy, fruit, and processed grains, and bit parts to vegetables and whole grains. They’re a lucrative target: Nutrition standards for the National School Lunch Program shape a $14 billion market across nearly 100,000 schools.
But those menus may be misaligned with the latest nutritional science, according to a new study—and have a much bigger environmental impact than they should.
In the journal Health Affairs, nutritionists at Harvard’s T.H. Chan School of Public Health compared public data on school lunch menus to the diet recommended by the EAT-Lancet Commission Report. The global food system accounts for about one-quarter of total carbon emissions, and the definitive 2019 report, peer-reviewed by leading global health researchers, aimed to design a ‘planetary health’ diet to maximize nutritional value while minimizing greenhouse gas emissions and land and water consumption—all at the lowest possible cost.
You’re probably familiar with some of the central tenets of the planetary health diet: Eat fewer animal products, especially beef, and more legumes and vegetables. And because transportation accounts for a very small portion of each food’s footprint, it doesn’t make a huge difference, carbon-wise, if the food is produced locally.
You also might have been able to guess: There are some pretty big gaps between school lunches and the EAT diet. Menus vary between school districts and grade levels, but overall the Health Affairs researchers found that National School Lunch Program (NSLP) menus disproportionately over-provide the most carbon-intensive foods, relative to EAT recommendations.
Dairy is particularly over-represented, thanks to the ubiquitous cartons of milk that are a cornerstone of the traditional American school meal. That’s in part because the EAT-Lancet recommendations are originally crafted for adults. Lead author Mary Kathryn Poole said that she and her colleagues adjusted for portion size, but otherwise left the EAT diet uncalibrated to the nutritional needs of children, for whom vitamin D and calcium are especially important.
Still, Poole said, the finding points to a low-hanging fruit for carbon reductions: Serve those nutrients another way. She pointed to a 2017 study in the American Journal of Public Health finding that students throw away nearly half the milk provided to schools, causing them miss out on 27% of the vitamin D and 41% of the calcium they’re supposed to receive.
In other words: In addition to its carbon footprint, milk is an ineffective nutrient delivery system because kids don’t drink it. But alternative sources of these nutrients include some of the categories encouraged by EAT: leafy greens and seafood.
The same kind of trade-offs are possible for the protein in meat-heavy NSLP meals: While the Health Affairs paper noted that school meals went overboard on beef, lamb, pork, and chicken, it also showed a dramatic under-reliance on a cheap form of protein: legumes.
Poole hasn’t yet completed a carbon inventory of current school lunch menus, so it’s not possible to put a number on how many tons of emissions would be saved by a widespread alignment with EAT. The question of relative cost, too, requires more data. But the average NSLP meal costs $3.81, and a preliminary calculation in the paper concludes that the EAT diet would, on average, cut that cost nearly in half. (Though switching to an EAT-aligned menu could entail other costs, notes Poole, in the form of new kitchen equipment and worker training.)
Because each school district can design its own menu to meet federal nutrition requirements, schools needn’t wait for congressional approval to tackle kitchen emissions. A number of districts nationwide already have a Meatless Monday program and increased vegetarian options. And because schools are such a major food purchaser, small tweaks to the menu can have a ripple effect across the economy.
“The food industry is responsive to changes toward sustainability,” Poole said. “Many food companies will reformulate products to meet the needs of a school lunch.”