Dr. Michael Mosley - 21-Day Keto Magic: Eat Healthy, Burn Fat, Lose Weight, and Keep It Off

I n 2012 my world was turned upside down when I was told that a recent blood test had revealed that I had Type 2 diabetes. But threats are sometimes opportunities, so that was also when I decided to re-examine my beliefs and prejudices and find out if there was something I could do to cure myself of what promised to be a nasty, progressive disease.

I did my medical training at the Royal Free Hospital, part of University College, London, in the early 1980s. The Royal Free was a wonderful medical school, but the five years I spent there left me with some pretty fixed beliefs about diet. These included the belief that fats were bad, carbs were good, fasting was ridiculous, probably dangerous, and if you discovered you had Type 2 diabetes then you had better start on medication ASAP, since we all knew that this was a lifelong disease for which there was no cure.

And yet the dean of the Medical School also told us, in a talk he gave on our first day there, that much of what we would learn during our studies would, in time, prove out of date, so we had better keep up with the research. Another thing he said, which I still remember vividly, was that four of us in the room, who had not yet met, would end up marrying each other. He was right. Clare, who is now my wife and who creates all the recipes for our books, was in that room listening to the same talk.

Anyway, fast-forward 30 years and there I was, in early 2012, a happily married father of four (albeit significantly overweight), being told by my lovely GP that I had an incurable disease which I knew would double my risk of heart disease and dementia, take up to 10 years off my life expectancy, probably make me impotent (75 percent of men with diabetes have erection problems) and increase my risk of having a finger or toe amputated 17-fold. It was a shock. I had already seen the impact that raised blood sugars had had on my father, who had been diagnosed with the same condition in his mid-fifties, at around the age I was then. Despite following medical advice, he had died of diabetes-related complications at the age of 74.

So, rather than follow my own doctors advice, which was to start on medication, I began to look around for alternatives. And that was when I discovered something called intermittent fasting.

Long story short, I decided to make a film for the eminent BBC Science series, Horizon, all about intermittent fasting called Eat, Fast, Live Longer. I wanted to see if I could use this approach to cure myself of Type 2 diabetes, or at least put it into long-term remission, something I was told was impossible.

I went to the United States, met a range of experts who were studying fasting, including Professor Valter Longo, a longevity specialist from the University of Southern California, and Professor Mark Mattson, a leading neuroscientist, based at the National Institute on Aging, and author of dozens of studies on intermittent fasting (or what he more correctly called intermittent energy restriction). Based on his advice, I put myself on a 5:2 intermittent fasting diet, lost 20 pounds and returned my blood sugars to normal.

That documentary had an astonishing impact. It helped trigger a worldwide interest in different forms of intermittent fasting, ranging from the 5:2 diet to Time-Restricted Eating. It also led me to develop a rapid weight loss program which forms the basis of this book.

The dean at the Royal Free Medical School was quite rightlike so much in medicine, the science behind diets and dieting is constantly evolving as we discover new things about the impact of particular foods on our bodies and brains. And Ive made a point of keeping up with the latest researchI really am obsessed with how to improve mood, sleep, and metabolic health and finding better ways to lose weight and keep it off.

Thats why Ive adapted and improved my extremely popular Fast 800 plan to accommodate new findings which highlight the importance of protein in the diet and the many health benefits of combining intermittent fasting with going keto.

Like intermittent fasting, keto was barely talked about back in 2012. A standard keto diet is one where you eat large amounts of fat and very little in the way of carbs, normally less than 50 grams (1.8 ounces) a daythe amount youd find in a bagel. The idea is that cutting right back on carbohydrates forces your body to rely on fat as its main source of energy. Without sugar, bread, pasta and rice, your body increasingly depends on your fat stores for fuel, converting them into ketone bodies, which puts your body into a state of ketosis.

Ketogenic diets promise rapid fat loss andas a bonusgoing keto should stop you from feeling hungry. So it is hardly surprising that keto has taken off, fast. By 2020, keto diet was the most Googled diet of all.

When a new diet or health regimen suddenly becomes popular, you can be sure it will soon be accompanied by misconceptions and confusion. And I will be honest, when I first heard about the keto diet it struck me as a nutritionists nightmare. The idea of eating lots of fat and very little in the way of carbs is pretty much the opposite of what most people regard as a healthy, sustainable diet.

Yet I discovered that, at least in the short term, a keto diet can work really well at suppressing appetite and helping people lose weight. It has been used, for more than 100 years, to treat epilepsy (as the brain increasingly relies on ketones for fuel, this reduces brain cell excitability and therefore seizures). And there is mounting evidence that it can help people with Type 2 diabetes return their blood sugars to normal, without medication.