Skim milk is widely thought to be the best choice for those aiming to lose weight and be healthier, but a new study found that people who consumed full-fat dairy had a lower risk of diabetes, compared to those who did not.

Researchers from Tulane University studied circulating blood biomarkers and 15 years of data for 3,333 adults participating in the Nurses’ Health Study and Health Professionals Follow-Up Study. They observed that those with the highest levels of dairy fat in their blood had a 46 percent lower risk of developing diabetes over the study span, compared to those who had the lowest levels of dairy fats in their blood,Medical Daily reported.

“I think these findings together with those from other studies do call for a change in the policy of recommending only low-fat dairy products,” study author Dr. Dariush Mozaffarian told Time.  “There is no prospective human evidence that people who eat low-fat dairy do better than people who eat whole-fat dairy.”

While many people shifted from regular dairy to skim in order to avoid the calories from full-fat dairy, past research has shown a tendency to replace fat with sugar or carbohydrates— two culprits that are even worse for diabetes risk. Three years ago, Swedish researchers observed that middle-aged men who ate high-fat dairy products were significantly less likely to become obese over 12 years, compared to men who never or rarely ate such foods, Medical Daily reported.

Mozaffarian noted that results are preliminary and should not yet be taken as diet advice.

The study was published March 22 in the journal Circulation.