The prevalence of type 2 diabetes is increasing sharply in developed and developing countries as a consequence of the increasing prevalence of overweight and obesity. Nutrition interventions should ideally address both individual-level and population-level change.  The major challenge is to prevent excessive weight gain, and ideally this should commence early in life. At the individual level the most important intervention is to prevent excessive energy intake, and to ensure a sufficient intake of protein and nutrients.  This can be achieved through a diet that restricts the intake of energy-dense, nutrient-poor processed foods high in saturated fats, added sugars and salt. Such a diet would contain minimally processed foods of low energy-density and high nutrient-density: fresh fruit and vegetables, nuts, pulses, leans meats, fish, eggs, some dairy products.  Liquid calories and large portion sizes should be minimized. The traditional Cretan Mediterranean diet of the 1950s provides one model, but there are many variations that are highly palatable.  The greatest potential for change, but also the greatest challenge is at the population level - to create an environment where ‘healthy choices are easy choices’. However, most developments in the industrialised food sector over the past 3 decades have been in the opposite direction. We have a food supply that has become increasingly ‘obesogenic’: energy-dense, nutrient-poor foods rich in sugars, fats and salt and frequently low in protein are widely and continuously available and portion sizes have increased significantly. These are the foods that are most intensively promoted.   Such processed foods are much more cost-effective in calories/$ than those foods being promoted for healthy eating – and are part of the explanation for the social gradients in both obesity and diabetes. Prevention of type 2 diabetes at the population level cannot be achieved without major transformation of the current food environment.