Going on the occasional low-calorie fast for four days could help you live longer, lose weight-and even make you smarter.
The four-day fast should be carried out once every three to six months, says Valter Longo, from the University of Southern California. But he warns against being too extreme. Don't go on a water-only fast, and diabetics shouldn't go on a fast at all.
Fasting is difficult for the vast majority of people, he says, which is why he's created the FMD, or fast-mimicking diet, which provides all the benefits of a no-food fast but without completely restricting food. It's a plant-based approach, and allows vegetable soup, energy bars, energy drinks, chamomile tea and a vegetable supplement.
Longo and his team have tested it on 19 people, who went on the diet once a month for three months, and then went back to their normal diet for the remaining 25 days or so of the month. At the end of the trial, their biomarkers for ageing, diabetes, heart disease and cancer had all reduced.
In earlier trials with mice, the diet also improved the biomarkers that are associated with cognitive abilities.
(Source: Cell Metabolism, 2015; doi: 10.1016/j.cmet.2015.05.012)