During World War II, millions of Americans planted “victory gardens” in their backyards, eventually supplying a hungry nation with 40 percent of its homegrown fruits and vegetables. Once the war was over, those urban farms withered away, supplanted by increasingly efficient large-scale rural agriculture.

Now urban farming is staging a curious comeback. In recent years, US cities like Detroit, Washington, DC, and San Francisco have set up programs encouraging people to grow crops in vacant lots or on rooftops. Michelle Obama has promoted the resurgence of community gardens. Advocates sometimes tout urban farming as the solution for “food deserts” in poor neighborhoods.

But do these programs actually make sense? Are there real social or environmental benefits to growing food within city limits? Or is urban farming just a well-meaning but ultimately insignificant hobby for urban elites?

One of the best explorations I’ve seen of this topic is this recent paper by Raychel Santo, Anne Palmer, and Brent Kim of the Johns Hopkins Center for a Livable Future. The authors were curious about some of the bolder claims being tossed around about urban farming — that it can revitalize blighted neighborhoods, say, or help combat food insecurity. So they did a deep dive into the published research.

What emerges is a nuanced picture. Urban farming likely won’t ever provide cities with all that many calories. And the environmental advantages are … debatable. But urban farms can provide a bunch of other neat benefits, from bolstering local communities to (sometimes) encouraging healthier diets. They can also give city-dwellers a better appreciation of how our food system works, which is less nebulous than it sounds.