Switching out that greasy cheese burger for a main dish of salmon cooked in plant-based oil and some vegetables could slow down the progress of Type 2 diabetes in some prediabetics, according to new research published in PLOS One.

An international team of researchers led by dietitian Nicola Guess from King’s College London found that replacing saturated fats — found in butter, cheese, red meat and other animal-based foods — with polyunsaturated fats, which are found in foods such as vegetable oils or nuts, could prevent “full blown” diabetes in prediabetics whose muscles do not absorb glucose properly. While previous studies have shown the effect of dietary fats on insulin sensitivity, this is the first to explore the differing effects dietary fats can have on prediabetic patients.

“This study is the first to explore whether we can target dietary advice taking into account the underlying differences in the two prediabetes states,” Guess said in a statement.

People are classified as prediabetics if they have blood glucose levels that are higher than normal but not quite high enough to have diabetes — a disease that affects more than 29 million Americans, and is the 7th leading cause of death, according to the American Diabetes Association. Previous research has found that prediabetes can be split into two distinct conditions: isolated impaired fasting glucose (IFG), a state in which the liver produces too much glucose; and isolated impaired glucose tolerance (IGT), a condition in which glucose is not taken up properly by the muscles.

For the study, researchers recruited 73 patients who had a wide range of insulin sensitivity, including athletic, slim and obese people who had normal levels of glucose in their blood, and people with prediabetes or Type 2 diabetes. They found that in those with IGT, replacing saturated fats with polyunsaturated fats helped slow down the development of diabetes in these high-risk patients. In people whose livers were producing too much glucose, reducing saturated fat had a beneficial effect in slowing down the development of diabetes, but replacing it with polyunsaturated fats had no effect.

Researchers believe the different effects dietary fats have on the two separate conditions of prediabetes could be due to polyunsaturated fats promoting “uptake of glucose by the insulin receptors in the muscles.”

“The findings suggest that increasing dietary intake of polyunsaturated fats may have a beneficial effect for patients with a certain type of prediabetes but also illuminates why certain dietary changes may have no effect on progression of type 2 diabetes in the other subtype,” Guess said.

Weight loss is currently regarded as the most effective way to slow down the progression of diabetes in prediabetic patients, but this dietary intervention could have an additional impact.

Past research has linked polyunsaturated fats to many health benefits, including a reduced risk of cardiovascular disease and early death.

Beyond the small size of the study, limitations included researchers not objectively measuring the physical activity levels of each participant, which could have influenced their results. Since the study was cross-sectional, researchers could not confirm causality between healthy dietary fats and the progression of diabetes. However, researchers hope to build on this work and test the results in a randomized trial.

Source: Guess N, Perreault L, Kerege A, Strauss A, Bergman B. Dietary Fatty Acids Differentially Associate with Fasting Versus 2-Hour Glucose Homeostasis: Implications for The Management of Subtypes of Prediabetes. PLOS One . 2016