A systematic review of the available studies up to 30 November 2009 assessed the effect of a Mediterranean diet in type 2 diabetes. Over seventeen studies, two large prospective studies report a substantially lower risk (83% and 35%, respectively) of type 2 diabetes in healthy people or in early diagnosed patients with the highest adherence to a Mediterranean diet. Five randomized controlled trials showed improvement of fasting glucose and HbA1c levels while not one study reported a worsening of glycaemic control with a Mediterranean diet.
Two controlled trials in a secondary prevention setting demonstrated that diabetic patients had cardiovascular benefits from a Mediterranean diet.
The researchers concluded, “The evidence so far accumulated suggests that adopting a Mediterranean diet may help prevent type 2 diabetes, and also improve glycaemic control and cardiovascular risk in persons with established diabetes”.
In another 2009 study, a low carbohydrate Mediterranean Diet was found to improve cardiovascular risk factors and diabetes control amongst overweight patients with type-2 diabetes (Elhayany, Lustman et al; 22 Sept, 2009)
Ref: http://www.ncbi.nlm.nih.gov/pubmed/20546959?dopt=Abstract