‘On the 5:2 I lost 9 KILOS and REVERSED MY DIABETES’

Dr Michael Mosley, the man who launched the 5:2 diet revolution, has refined and revised his original plan – followed by Hollywood stars and politicians as well as millions of Britons – with the help of the latest scientific research

THE 5:2 DIET, FIVE YEARS ON This year’s Oscars ceremony will be remembered chiefly because the producers of La La Land were mistakenly told they had won Best Picture and then had to hand the award back. I, however, was far more interested in the appearance of the host, comedian Jimmy Kimmel, than anything else that was going on. Jimmy is a big fan of the 5:2 diet, which he credits with helping him lose 30lb and keep it off. ‘It has helped me stay at 182lb,’ he said in a recent interview, ‘and made me appreciate the food that I eat.’ (I am happy to report that as well as looking slim and healthy, Jimmy was also very funny.)

The 5:2 diet has changed my life, but it came about largely by chance. Five years ago I discovered that, like my father, I had become a type 2 diabetic. My father died at the relatively early age of 74 from complications of diabetes and I was desperate not to follow in his footsteps. So rather than start on medication I looked for alternative ways to improve my blood-sugar levels and came across something called intermittent fasting. This led to my making a documentary, Eat, Fast and Live Longer, and writing a book, The Fast Diet, with journalist Mimi Spencer, which became an international bestseller.

THE KEY: FASTING

‘Intermittent fasting’ is not fasting in the sense that you are going entirely without food. You are simply cutting back on your calories a few days a week. There are many different approaches, from alternate day fasting to the 16:8 diet (see page 38), but the 5:2 (reducing your calories to around 600 a day, twice a week) is the one that many people find easiest to do.

On the 5:2 I lost 9 kilos and reversed my diabetes. The TV presenter Phillip Schofield told me that it has become a way of life for him. I’ve read in the press that it has been embraced by celebrities such as Beyoncé, Benedict Cumberbatch (‘you have to, for Sherlock’), Liv Tyler, Ben Affleck and Christie Turlington. I have also had messages of thanks from thousands of people, ranging from, ‘I lost 40lb and a year later

the weight is still gone’ to ‘I can now take my jeans off without undoing them and I am happy to do so if anyone wants to watch!’

When I wrote The Fast Diet back in 2012 there was already compelling evidence of the health benefits of intermittent fasting. Since then there have been many more studies showing that it can not only lead to significant weight loss but also trigger changes within the body that reduce your risk of a range of diseases. A recent review article, published in the science journal Cell Metabolism, concluded that intermittent fasting ‘helps reduce obesity, hypertension, asthma and rheumatoid arthritis. It has the potential to delay ageing and help prevent and treat diseases.’

SO HOW DOES IT WORK?

Many people find cutting their calories a couple of days a week more doable than being on a constant diet. A study carried out in Manchester, which involved more than 100 women, found that those on the 5:2 lost nearly twice as much fat as those allocated a standard diet. They were also far more likely to stick to it.

Intermittent fasting also switches on repair genes, whose job it is to keep your body in good shape. We tend to treat our bodies like a car: we keep it topped up with high- calorie fuel and drive it hard. If you do that it will, eventually, break down. It’s only when you go for long periods without food (around 12 hours) that your body switches to ‘clean up and repair’ mode.

Going on a short fast is a bit like taking your body along to the garage. Freed from their normal routine work, the little gene mechanics start doing urgent maintenance tasks. Part of that involves something called autophagy. Autophagy, meaning ‘self- eat’, is a natural process during which the body breaks down and recycles old and tired cells. Just as with a car, it is important to get rid of damaged or ageing parts if you want to keep things in good working order.

Fasting not only helps clear out damaged old cells but can also spark the production of new ones. In a fascinating study published a couple of weeks ago, Professor Valter Longo of the University of Southern California showed that in mice, if he cut down their calories for a few days a month, he could regenerate parts of their pancreas.

Your pancreas produces the hormone insulin, which brings down your blood-sugar levels when they get too high. In diabetics the insulin-producing cells in the pancreas are damaged and they no longer work properly, which means diabetics often end up having insulin injections. It is extremely exciting to see that fasting could reverse this damage.

Professor Longo has also shown that intermittent fasting can boost the immune system. If you do a short fast and then eat, you get a rebound effect, with the creation of new, more active white cells. ‘We could not have predicted,’ he told me, ‘that fasting would have such remarkable effects.’

I’ve read that the 5:2 has been embraced by celebrities such as Beyoncé, Benedict Cumberbatch, Liv Tyler and Ben Affleck

OTHER METHODS OF INTERMITTENT FASTING

There are a number of other options, including alternate day and the so- called 16:8 diet. The latter has been popularised by X-Men actor Hugh Jackman, who credits it with helping him develop his impressive physique.

To do a 16:8 diet you cram all your calories into an eight-hour window and then fast for 16 hours. There have been a number of rat studies that have shown that this can be beneficial, but so far the only lengthy human study that I know of was carried out for a television series I present, Trust Me, I’m a Doctor.

For this study we teamed up with Dr Jon Johnston of the University of Surrey. We recruited 16 volunteers and randomly allocated them into two groups. One group continued as normal. The other was asked to eat the same amount of food as normal, but to eat their breakfast 90 minutes later than usual and have their evening meal 90 minutes earlier. They were not allowed to snack in between, which meant they were going three hours longer each night without food.

After ten weeks we found that, compared to the control group, the group who had restricted their mealtimes showed significant improvements in their cholesterol and blood-sugar levels. They also lost more body fat. Sticking to a regime like this can be tough, but this study does suggest that delaying breakfast or eating dinner a bit earlier brings benefits.