Eating "healthy" fats found in vegetable oil, nuts, and fish could keep diabetes at bay by improving the body's regulation of blood sugar.
Substituting these fats for carbohydrates and "saturated" fat from meat and dairy products reduces risk factors for Type 2 diabetes, according to an analysis of more than 100 studies.
Researchers looked at how the foods people ate affected measures of metabolic health, including blood sugar levels, and the ability to produce and respond to the hormone insulin.
Diets rich in monounsaturated or polyunsaturated fats had a beneficial effect on key markers of blood sugar control.
"Our findings support preventing and treating these diseases by eating more fat-rich foods like walnuts, sunflower seeds, soybeans, flaxseed, fish, and other vegetable oils and spreads, in place of refined grains, starches, sugars, and animal fats," said lead scientist Dr Dariush Mozaffarian, from Tufts University in Massachusetts.
"This is a positive message for the public. Don't fear healthy fats."