Reducing caloric intake slows down metabolism and ageing, a new comprehensive study has found. Findings show that a low-calorie diet could prolong health in old age.

Researchers looked into the link between by-products of metabolism causing oxidation and an increased risk for age-related neurological conditions. Their study was published in the journal Cell Metabolism.

It has found that participants who cut their diets lost an average of about nine kilos. They also displayed fewer signs of slower metabolisms and oxidative stress. Examples of age-related neurological conditions are Parkinson’s diseases, cancer, Alzheimer’s, arthritis and diabetes.

Scientists from Pennington Biomedical Research Center conducted the study by recruiting 53 people between the ages of 21 and 50. The participants, who were not obese, reduced their calorie intake by 15 percent over two years.

Leanne M Redman, an associate professor of clinical services at Pennington and lead author of the study, said that restricting calories can slow basal metabolism. She explained that if by-products of metabolism accelerate ageing processes, calorie restriction sustained over a number of years may help decrease the risk of chronic disease and prolong life.

Another finding was that there are no adverse effects of prolonged calorie restriction. Instead, it leads to improvements in mood and health-related quality of life.

Redman said the trial “rejuvenates support for two of the longest-standing theories of human ageing: the slow metabolism rate of living theory and the oxidative damage theory.” She noted that upon examining animal data, cutting calories by 25 percent may extend life expectancy by as much as seven years. “Eating a well-balanced diet with fewer calories does have benefits for the secondary causes of ageing,” she added.

Meanwhile, scientists have found that a five-day diet called Fasting Mimicking Diet (FMD) improves longevity and cuts the risk of cancer and diabetes by half.

Professor Valter Longo, USC Davis School of Gerontology and director of the USC Longevity Institute, said that strict fasting is difficult for people to stick to. Longo warned that it can also be dangerous. That is why they developed a complex diet that triggers the same effects in the body.

“I think based on the markers for ageing and disease in humans it has the potential to add a number of years of life but more importantly to have a major impact on diabetes, cancer, heart disease and other age-related disease,” The Telegraph quotes Longo as saying.