The prevalence of type 2 diabetes, a disease difficult to treat and expensive to manage, is increasing rapidly worldwide. It is also known that lifestyle, and particularly dietary habits, play an important role in the development of diabetes. Adherence to a healthy dietary pattern, like the Mediterranean diet, exerts a beneficial role regarding the development of diabetes. Additionally certain individual food groups and components of the diet, such as monounsaturated fatty acids, fruits, vegetables, whole grain cereals, dietary fiber, fish and moderate consumption of alcohol, also may protect against the development of diabetes, possibly through the amelioration of insulin sensitivity and their anti-inflammatory actions. Unfortunately, dietary habits in the developed world are changing towards an unhealthier direction. Consequently, emphasis should be given on encouraging at population and individual level for adopting a healthier lifestyle, including dietary habits, in order to prevent the development of type 2 diabetes.