Insulin resistance is a condition present before the onset of type 2 diabetes. Too little physical activity and a diet consisting of high glycemic index foods, which are foods that cause the blood sugar to raise rapidly and high, can contribute to insulin resistance.
Muscles use glucose as fuel to produce energy. The research reviewed evaluated if an increase in muscle mass is associated with improved glucose regulation (Srikanthan P, Karlamangla AS. 2011). Data from 13,644 participants were evaluated to assess insulin resistance, prevalence of transitional/pre- or overt diabetes and prevalence of overt diabetes.
The researchers concluded that higher muscle mass is associated with better insulin sensitivity and a lower risk of diabetes.
Having higher muscle mass would also be beneficial as we get older since it can help us be more functional.
If you are not already doing so, add some resistance training to your regime.