Eating pistachios may help lower blood sugar and insulin levels and reverse some indicators of pre-diabetes, according to a study done in Spain.

Researchers found pistachios may promote healthier metabolism in people with pre-diabetes because the protein, fats and fiber in the nuts can help lower blood glucose. The study was published in this month’s Diabetes Care, a scientific journal of the American Diabetes Association.

The randomized, crossover and controlled clinical study ran 2011 to 2013, consisting of 54 adults with pre-diabetes divided into two groups.

One group ate 2 ounces of pistachios daily for four months, and then followed a control diet of olive oil and other fats instead of pistachios for four months. The second group began with the control diet followed by the pistachio diet. The diets were matched for protein, fiber and saturated fatty acids.

The researchers confirmed fasting blood sugar levels, insulin and hormonal markers decreased significantly during the pistachio diet compared to the control diet, where these levels and markers actually increased.

Signs of inflammation were also reported to have decreased among the pistachio diet.

Neither group experienced weight gain.

“This is good news for the many people who may be at risk of developing type 2 diabetes,” Arianna Carughi, nutrition consultant to American Pistachio Growers, said in a news release. “Additionally, pistachios are lower in calories than other nuts and have higher levels of bioactive compounds like lutein, beta-carotene, gamma tocopherol and phytosterols.”

The study was funded in part, but not designed, by the American Pistachio Growers.