Type 2 diabetes mellitus (T2DM) is a highly prevalent condition and is associated with a number of metabolic risk factors such as excess of weight, impaired lipid profile and higher levels of blood pressure. As other complex diseases, it is strongly related to an environmental component such as sedentarism and unhealthy diet, and also to a genetic component. A cluster of variants (polymorphisms) in a large number of genes seem to interact with nutrients/dietary factors in modulating cardiometabolic parameters in healthy individuals. The role of total calories intake and also different kind of carbohydrates and dietary fats in worsening the excess of weight and/or metabolic profile in patients with diabetes is well known, but the extent to which genetic factors can modify these associations is not yet fully understood. Therefore, the aim of this mini-review is to discuss the interaction of genetics and diet in the T2DM setting, since both are strongly involved in the genesis and development of the disease.