Human life expectancy has been increasing steadily for almost two centuries and is now approximately double what it was at the beginning of the Victorian era. This remarkable demographic change has been accompanied by a shift in disease prevalence so that age is now the major determinant of most common diseases. The challenge is to enhance healthy ageing and to reduce the financial and social burdens associated with chronic ill health in later life. Studies in model organisms have demonstrated that the ageing phenotype arises because of the accumulation of macromolecular damage within the cell and that the ageing process is plastic. Nutritional interventions that reduce such damage, or which enhance the organism's capacity to repair damage, lead to greater longevity and to reduced risk of age-related diseases. Dietary (energy) restriction increases lifespan in several model organisms, but it is uncertain whether it is effective in primates, including humans. However, excess energy storage leading to increased adiposity is a risk factor for premature mortality and for age-related diseases so that obesity prevention is likely to be a major public health route to healthy ageing. In addition, adherence to healthy eating patterns, such as the Mediterranean dietary pattern, is associated with longevity and reduced risk of age-related diseases.