If you’re wavering among carrots, tomatoes, or spinach to accompany your next meal, go for the greens. Researchers at the University of Vienna in Austria have discovered that when green vegetables break down, they release something call sulfoquinovose (SQ), a plant-derived sugar, which in turn provides essential food for good gut bacteria to feast on.

“Our research has found that SQ promotes gut microorganisms known to be associated with healthy individuals,” says lead study author Buck Hanson, Ph.D. Specifically, SQ is broken down into acetate and hydrogen sulfide, metabolites that support the body in functions ranging from brain signaling to appetite regulation to cardiovascular health, says Hanson. (To figure all this out, the scientists studied the fecal samples from a group of vegetarians—hello, plant poopers—and worked their way backwards to figure out the influence of SQ on gut microbes.)

The tricky part: Researchers are still determining exactly how much of the green stuff you need to eat for maximum results that enhance good gut bacteria.

“It is too early for us to put a number on what is a healthy level of SQ consumption,” says Hanson, who confirms spinach has the highest amount of SQ of all the leafy green options.

Nevertheless, along with health-enhancing microbes, “there are other clear benefits to eating green vegetables, including their vitamin and mineral content, antioxidant properties, and dietary fiber.”

To get your SQ-loaded greens, try a Swiss chard and Swiss cheese omelet for breakfast, add kale to your lunch salad or sandwich, and steam yourself a side of spinach to go with your dinner.