Walnuts which are rich in polyunsaturated fatty acids (PUFAs) and alpha-linolenic acid (the plant-based omega-3 fatty acid) can reduce insulin resistance. A group of researchers from the Harvard School of Public Health followed 58,063 women aged 52-77 years old from 1998 to 2008 and 79,893 women aged 35-52 years old from 1999-2009, both groups without diabetes, cardiovascular disease, or cancer at baseline, to study the relationship between walnut consumption and diabetes. The findings showed that two or more servings (1 serving = 28 grams) of walnut can reduce 21% and 15% risk for type 2 diabetes in those two groups respectively.

Researchers found that walnuts contain high amounts of polyunsaturated fatty acids (PUFAs) while other nuts mainly have mono saturated fatty acids. More importantly, walnut is the only nut that has a significant amount of alpha-linolenic acid, the plant-based omega-3 fatty acid. Those fatty acids that walnuts contain can help reduce insulin resistance.