For the past two years, school lunches at the Oakland Unified School District have been a little different. As part of a study to find out if reducing the amount of meat and cheese in school meals would affect climate change, the students were served meals modified with just one-third less meat than before. And the results were impressive: Not only was the district’s carbon footprint reduced significantly, but there were also huge savings in cash and water.

For the study, environmental advocacy group Friends of the Earth (FoE) worked with the Oakland schools to reduce meat and dairy, and to asses the impact of this reduction on the carbon and water footprint of the entire district’s meals. During the two-year period of the study, schools reduced their purchases of animal products by just 30%, leaving enough meat for even the most militant carnivores, and yet managed a reduction of 14% in carbon. For the district as a whole, that translates to around 660 tons of CO2 saved per year, or, says the FoE report, “the equivalent of driving 1.5 million miles less per year.”

But there are many more benefits. For example, water use–the water required to produce the animal products–was reduced by 6%, or 42 million gallons. That’s a staggering seven gallons per meal saved just by cutting animal products by a third.

Cutting out meat also saves money. The district as a whole saved $42,000, which equates to a 1% reduction in spending per meal. That alone isn’t such a big figure for an entire school district, but it includes the additional money spent on fruit and vegetables to replace the meat and cheese. In fact, schools purchased 10% more fruits, vegetables, and legumes, which translates to a healthier diet for all involved.

To help with the reduction in animal products, plans like Meatless Mondays were adopted by over 200 schools across the district. Where meals are prepared on-premises, reduced-meat meal planning was easy to incorporated. Where pre-prepared meals were delivered, food-service companies could often provide either vegetarian options or plant-based meals that incorporate just some meat. A beef burger could be replaced by a mixed beef and mushroom burger, for example. Another option, used by schools in the district, is to purchase high-quality, locally sourced organic meat from dairy cows. The greenhouse-gas footprint of these animals is much lower because one cow does double-duty as both milk producer and meal.

Implementation, then, is easy. The barrier comes from politics and entrenched business interests, but those can be overcome.

If every K-12 school in California did the same as the Oakland Unified School District, it would reduce CO2 emissions by over 88,000 tons, “equivalent to eliminating the emissions from 17,000 cars that drive almost 200 million miles per year,” says FoE. If every school in the U.S. followed the plan, it would be like taking 150,000 cars off the roads each year.