Age is a risk factor for numerous diseases. Although the development of modern medicine has greatly extended the human lifespan, the duration of relatively healthy old age, or ‘healthspan’, has not increased. Targeting the detrimental processes that can occur before the onset of age-related diseases can greatly improve health and lifespan. Healthspan is significantly affected by what, when and how much one eats. Dietary restriction, including calorie restriction, fasting or fasting-mimicking diets, to extend both lifespan and healthspan has recently attracted much attention. However, direct scientific evidence that consuming specific foods extends the lifespan and healthspan seems lacking. Here, we synthesized the results of recent studies on the lifespan and healthspan extension properties of foods and their phytochemicals in various organisms to confirm how far the scientific research on the effect of food on the lifespan has reached.

Different scenarios for an ageing society presume different approaches to the meaning of old age. One scenario anticipates a Prolongation of Morbidity, where quality of life concerns might permit active euthanasia or suicide as a means of saving money. Those who believe in a Compression of Morbidity opt for health promotion to delay morbidity in favour of productive ageing. Optimists look to a scenario of Lifespan Extension, where scarce health resources are not expended for incremental gains in life expectancy but rather for basic research to postpone or eliminate ageing. Finally, those who emphasize Voluntary Acceptance of Limits identify the meaning of old age with voluntary acceptance of finitude, where claims of future generations might limit longevity for any one generation. Thus, contrasting meanings such as quality of life, productive ageing, indefinite survival and voluntary limits entail very different consequences for the allocation of scarce resources across age-groups and among sub-groups of the elderly population.