Sadie Rain Hope-Gund and Safiyah Kai Russell Riddle star in “What’s On Your Plate?” screening Wednesday at the Russell Youth Center.

An earnest documentary about sustainable agriculture gets a bit of a boost when it’s being shown — with snacks — by a fast-food chain, and that’s what happens Wednesday at the Russell Youth Center when Chipotle offers a free screening of the film “What’s On Your Plate?”

Chipotle, though, has an avowed commitment to locally sourced food and gets a boost of credibility from the local CitySprouts public school garden program and Cambridge Health Alliance.

“The movie is a kid-friendly story about two middle schoolers on a quest to find out where their food comes from,” said Kimberly Green Goldstein, program manager for the co-sponsoring CitySprouts.

From the creator’s website:

The girls address questions regarding the origin of the food they eat, how it’s cultivated, how many miles it travels from the harvest to their plate, how it’s prepared, who prepares it and what is done afterward with the packaging and leftovers. They visit the usual supermarkets, fast food chains and school lunchrooms. But they also check into innovative sustainable food system practices by going to farms, greenmarkets and community-supported agriculture programs. They discover that these programs both help struggling farmers to survive on the one hand and provide affordable, locally grown food to communities on the consumer end, especially to lower-income urban families.

Whatever suspicion might come with a movie promoted by a fast-food chain, even one painted so green, the movie also has appreciative blurbs from foodie and environmental royalty such as Michael Pollan, author of “In Defense of Food: An Eater’s Manifesto” and “The Omnivore’s Dilemma” (he said “‘What’s On Your Plate’ is exactly the film we need now”) and Alice Waters, chef, author and founder of the Edible Schoolyard (who said the film “can have a real impact on the way we think about what we’re eating”).

Catherine Gund produced and directed the film; her daughter Sadie Rain Hope-Gund and her daughter’s friend Safiyah Kai Russell Riddle are its 11-year-old stars and get credit as co-producers.

Chipotle, which has expanded to most of Cambridge’s squares with T stops, is offering free snacks and drinks during the 76-minute movie, Goldstein said.

The screening begins at 6:30 p.m. The youth center is at 680 Huron Ave.