But a new study published in Science Advances paints a more complicated picture. While organic produce is likely marginally healthier to eat and, in some ways, more sustainable to grow, there are also downsides.

For starters, organic fruits and vegetables typically cost more than their conventional equivalents. To be certified as organic, a distinction set by the United States Department of Agriculture, farmers must meet specific criteria, including growing produce without the use of genetic engineering and chemical inputs. Without these methods, the growing process typically requires more manual labor, time, and money, a cost that is passed down to consumers.

And while it’s true that in many ways, organic is more sustainable than conventional farming—studies have shown organic farms support more biodiversity and, because they don’t use pesticides, are safer places to work for farm hands—when it comes to environmental concerns such as greenhouse gas emissions and water nitrogen loss, the comparison gets murkier. Organic farms produce less emissions per acreage. However, because they are barred from using genetic engineering, pesticides, and other methods that increase efficiency, organic farms also produce an estimated 19% to 25% less yield than conventional farms. While there isn’t a whole lot research on the topic, the few studies that do exist suggest green gas emissions and water loss might actually be higher on organic farms, on a per unit basis, says study author Verena Seurfert. “If we examine conventional and organic farms and compare them in terms of units of food produced, than organic doesn’t fare so well.”

In addition, while organic produce is likely more nutritious than conventional fruit and vegetables, there’s not a lot of evidence to support the claim that these often marginal discrepancies impact consumer health, Seurfert says. The same is true for pesticide residue: in developed countries, where pesticide use is tightly regulated, there’s no scientific consensus on how these often marginal difference impact human health.

Still, Seurfert stresses that if you can afford to eat organic, you should do so. Organic farms provide safer work environments for workers, plus they support great biodiversity. The real takeaway from her study is not that organic is bad but that the practice needs more study to in order to increase yield without lowering sustainability.

But if you can’t afford to buy organic produce, don’t stress too much. Particularly from a nutritional perspective, the most important factor is that you’re eating enough fruits and vegetables—organic or not.