Fast Fix?

From the 5:2 to Monday juicing, fasting diets promise huge health benefits. But does the science stack up? Charlotte Haigh investigates the pros and cons of going hungry

- Charlotte Haigh

Everyone from Beyoncé to Miranda Kerr has raved about the advantages of fasting, and in some studies science backs up its incredible health benefits. Restricting calorie intake for intermittent periods has been shown to increase energy, reduce internal inflammation, lower blood pressure and shrink fat around your middle – all factors linked with conditions from heart disease and cancer to dementia. It could even have an anti-ageing effect, too, by rebooting your body’s cells and switching on youth-boosting genes – not to mention the obvious weight-loss benefits. In some studies, even when overall calorie intake was the same, people who fasted for set periods lost more weight. ‘One of the quickest ways to resensitise cells to insulin (the hormone that helps your body use the energy in food) is through fasting, so it’s good for conditions caused by insulin resistance, like pre-diabetes, Type 2 diabetes and PCOS [polycystic ovary syndrome],’ says nutritionist and fasting expert Stephanie Moore*. So far, so amazing. But the research is in its infancy and fasting isn’t for everyone. ‘A lot of the studies have been done on animals and we need more research to see if the effects are the same in humans,’ says Dr Michelle Harvie, a research dietitian who has studied calorie restriction for preventing breast cancer. Still, the science is sufficiently promising for one researcher, Dr Valter Longo, director of the Longevity Institute at the University of Southern California, to have adopted a fasting regime himself. ‘Fasting may be an old concept,’ he says. ‘But now there’s science to back it up. Twenty years of research proves the body responds in a range of positive ways.’ We explore the benefits of four modern methods to fast.

THE PART-TIME FAST

What is it?