A UK-US research team has discovered that restricting calorie content can lengthen life. The results of the study, published in the journal Science, show that eating fewer calories can lead not only to a longer life, but a healthier one too, avoiding much of the disease that often plagues people in their later years. The team, from University College London, UK, the University of Southern California (USC) Davis School of Gerontology and Washington University School of Medicine in St Louis, US, carried out calorie restriction tests on rodents and found that restricting their food intake had a significant effect on the molecular pathways that are related to the ageing process. The results also showed that in less complex organisms, limiting calorie content may double or even triple life span. But the first author of the study, Professor Luigi Fontana from Washington University Medical School, said that increasing people's quality of life and helping them develop fewer ageing-related illnesses was the main aim of the research. 'The focus of my research is not really to extend lifespan to 120 or 130 years,' he explained. 'Right now, the average lifespan in Western countries is about 80, but there are too many people who are only healthy until about age 50. We want to use the discoveries about calorie restriction and other related genetic or pharmacological interventions to close that 30-year gap between life span and 'health span.' However, by extending healthy life span, average life span also could increase up to 100 years of age.' The research team cut the calorie content of rodents by between 10% and 50%, one of the main results of which was a decrease in the activity of pathways involving insulin-like growth factor (IGF-1) and glucose. Cutting calories in this way increased the life span of the rodents by a considerable amount, diminishing their susceptibility to diseases related to ageing including cancer, cardiovascular conditions and cognitive problems. 'About 30% of the animals on calorie restriction die at an advanced age without any diseases normally related to ageing,' said Professor Fontana. 'In contrast, among animals on a standard diet, the great majority (94%) develops and dies of one or more chronic diseases such as cancer or heart disease. In 30% to 50% of the animals on calorie restriction, or with genetic mutations in these ageing-related pathways, health span is equal to life span. They eventually die, but they don't get sick.' The research is particularly relevant given current soaring levels of obesity in the Western world. Being overweight or obese can lead to many serious illnesses including cardiovascular disease, diabetes and certain types of cancer. Childhood obesity is a particular worrying problem as thousands of children grow up eating a junk food diet that could trigger chronic health and weight problems in adult life. Professor Fontana believes that current dietary lifestyle trends mean that the 30-year gap between health span and life span is likely to expand rather than shrink. Our life span may also be reduced as thousands of people develop preventable dietary-related diseases such as type 2 diabetes. But he believes that if nutrition researchers understand how much calorie restriction can lengthen life and make people healthier, it may be possible to develop medicines that influence pathways affected by calorie restriction to keep people healthier as they age. Advice on diet has always been based on epidemiological data, but the latest research shows that it makes sense from a molecular viewpoint as well, he said. 'Now we have moved from epidemiology to molecular biology. We know that certain nutrients, as well as lower calorie intake, can influence IGF-1 and other pathways. Soon we hope to be able to use that knowledge to help people live longer and healthier lives.'