London - Halving the number of calories you eat on five days a month can help you live longer, research suggests.
People who underwent less than a week of a heavily restricted diet showed fewer signs of ageing, diabetes, heart disease and cancer compared to a group who did not fast.
And the good effects lasted even when they returned to their normal diet.
Previous studies have shown that strict fasting for short periods – surviving on just water alone – promotes health, but is not practicable for most people, particularly the old and frail.
So the researchers created a “fasting mimicking diet”, where the beneficial effects of fasting were replicated, but with vital vitamins and minerals were included “to minimise the burden of fasting”.
The medically supervised diet cut the number of calories eaten by between 34 to 54 percent. On the first day, the subjects ate just 1 090 calories while the diet was restricted to 725 calories on the second to fifth days.
The diet comprised vegetable soups, energy bars, energy drinks, crisp snacks, chamomile flower tea, and a vegetable supplement formula tablet. It was composed of 11-14 percent proteins, 42-43 percent carbohydrates, and 44-46 percent fat.
For the remaining 25 days a month, participants went back to their normal diet which they were not asked to change.
Tests found that over a three-month period, blood glucose levels fell 10 percent during the fasting days but remained around six percent lower overall. A chemical called circulating IGF1 which is associated with diseases of ageing in humans was reduced by 24 percent. Valter Longo, the lead researcher of the University of Southern California said: “Strict fasting is hard for people to stick to, and it can also be dangerous, so we developed a complex diet that triggers the same effects in the body.”
Although the study, published in Cell Press, on humans involved only 19 subjects, it mirrored research by the same University of Southern California team on mice. The rodents underwent the diet for four days twice per month.
The researchers found that cells in the mice – including bone, muscle, liver, immune cells and even brain showed signs of regeneration. The animals also lived longer, suffered fewer inflammatory diseases, cancer and showed improved learning and memory and less bone loss.
The human study will be expanded to 50 to 60 participants, followed by a trial with 500 to 1 000 participants.
Daily Mail