Glucose intolerance represents a spectrum of abnormalities, including impaired fasting glucose, impaired glucose tolerance and type 2 diabetes. It is a major public health challenge worldwide, with rapidly increasing prevalence rates in both developed and developing countries. This global epidemic of diabetes is largely driven by the globalisation of Western culture and lifestyles. Specifically, there is now evidence from large-scale observational studies, and from intervention studies, of powerful synergistic interactions between diet, obesity, exercise, smoking and alcohol in the development of glucose intolerance. It is estimated that > 90 % of cases of type 2 diabetes in the population could be prevented with the adoption of a prudent diet (high in cereal fibre and polyunsaturated fatty acids and low in trans-fatty acids and glycaemic load), avoidance of overweight and obesity (BMI < 25 kg/m2), engagement in moderate to vigorous physical activity for at least 05 h/d, non-smoking and moderate alcohol consumption. These findings are biologically plausible and have major public health implications. They form the basis for a clear, simple and coherent message for health promotion and public policy. However, to make progress on these issues health will need to be placed at the centre of public policy and relevant vested interests tackled, notably in the food, entertainment, tobacco and automobile industries.