"FastDiet' Book Is Attracting Dieters, and Doubters

Michael Mosley is the author of the new diet book called "The FastDiet." He is also starring in a PBS series that will air April 3. (Photo: Rebecca McAlpin for USA TODAY)

The FastDiet: Lose Weight, Stay Healthy and Live Longer With the Simple Secret of Intermittent Fasting (Atria Books, $24), by British physician Michael Mosley and writer Mimi Spencer, is No. 46 on USA TODAY's Best-Selling Books list. Mosley stars in an upcoming three-part PBS series. The first part, Eat, Fast and Live Longer With Michael Mosley, airs April 3.
The diet has a following in the United Kingdom, including some cardiovascular surgeons, TV journalists, chefs and celebrities.
But the book is generating a bit of controversy on this side of the pond. Obesity experts in the USA say the diet may be hard for many people to adhere to, and more research needs to be done to determine if it's safe and effective. And one U.S. researcher doesn't like how her work was used in the book to support the diet.
"I am a scientist at heart and I do not remotely claim that this is the be-all and end-all," Mosley says. "It's just the beginning of something interesting. People need to try it for themselves and see if it works."
Mosley, 55, who works for BBC as a medical journalist, says that when he first read about the alleged benefits of intermittent fasting, he was skeptical, too. "Nothing in my medical training had prepared me for this," he says. Although most of the world's great religions advocate fasting for faith purposes and some for health purposes, it seemed drastic and difficult to him.
But then Mosley had some medical tests done and discovered he had some risk factors for heart disease and diabetes, and he was a bit too heavy. "My doctor recommended I go on medication for high blood sugar and high cholesterol. She predicted that in 10 years I would be on eight different medications. I decided I wanted to find a different way."
So he asked his boss at BBC if he could use himself as a "guinea pig" to explore the science behind life extension, which focuses on calorie restriction and fasting.
Based on his review of the research, he created what he calls the "5:2 diet." Five days a week, he eats normally; two days a week, he eats 600 calories. For women, he recommends 500 calories on the fasting days. That would be about two poached eggs on a slice of whole-grain toast and a bowl of raspberries for breakfast, and roast salmon with green beans and cherry tomatoes for dinner.
Daily caloric needs vary depending on gender, age, height and physical activity level. An older sedentary woman might need only 1,600 calories a day to maintain her weight, while an active younger man might need 3,000.
Mosley divides his calories on the fasting days into two meals - breakfast and lunch. "You can have it all in one meal if you fancy. I found I was really quite irritable if I didn't have breakfast." He eats 300 calories at breakfast, often eggs with a bit of ham, and 300 calories for dinner - lots of vegetables and a lean protein. During the day he drinks lots of fluids, such as water, tea and coffee.
If people eat 500 or 600 calories on the two fasting days each week and don't significantly overeat on the "feed days" the rest of the week, they will lose weight in a steady fashion, he says. Mosley didn't find himself overeating on the feed days.
So what about feeling hungry? "I've gotten used to it. Hunger is one of those things that generally passes," Mosley says.
Where he used to grab sugary treats when he was hungry, he now snacks on vegetables. "I crave vegetables because they're what I satisfy myself with on a fasting day."
Some people worry that intermittent fasting will make them unable to focus, he says. "What I've discovered is that it sharpens my senses and my brain."
He thinks the plan may work for some people because it doesn't require the deprivation that characterizes many diet plans. Dieters still get to enjoy the foods they love, most of the time, he says.
Before he started intermittent fasting, Mosley, who is 5-foot-11, weighed 187 pounds and had a body mass index of 26, which put him into the overweight category. His waist was 36 inches; his neck, 17. His fasting blood glucose (a measure of diabetes risk) was too high, along with his cholesterol.
After two months on his program, he weighed 168 pounds, a loss of 19 pounds. He had a body mass index of 24, and his waist was 33 inches. His neck size was 16. His cholesterol and blood glucose and other factors fell to the normal range.
"I didn't want to lose any more because my wife, who is a doctor, said I was looking gaunt. These days, I fast one day a week, and often skip lunch on the other days."
One scientist who studies fasting takes exception to the way some of her work was used in the book. "My research on alternate-day fasting has been misrepresented in the book," says Krista Varady, an assistant professor of nutrition at the University of Illinois-Chicago. "He is using my research, which looks at fasting three to four days a week, to support his diet, which encourages fasting two days a week."
But Mosley says he was partly inspired to try the 5:2 approach after reading research done by Michelle Harvie, a dietitian in England who wrote The 2-Day Diet.
U.S. obesity experts say Mosley's plan may work for some, but many questions remain.
"I am aware of only one randomized, controlled trial that compared conventional daily calorie restriction with the 5:2 diet plan," says Samuel Klein, director of the Center for Human Nutrition at the Washington University School of Medicine in St. Louis. "In that six-month trial, weight loss and most health benefits from weight loss were the same in both groups.
"Additional and longer-term studies are needed to fully evaluate the effectiveness of the 5:2 diet approach and to determine which people might be more compliant with intermittent fasting than conventional daily calorie restriction," he says.
Klein says the real question is this: "Is it easier for people to starve two days a week than to reduce their calorie intake every day?"
"We do not know whether intermittent fasting has independent health benefits beyond weight loss alone," he says. "In rodents, alternate-day fasting has metabolic health benefits without a change in body weight," he says. However, alternative-day fasting in people causes weight loss, so it's difficult to separate the benefits of intermittent fasting from those of the weight loss itself, he says.
Tim Church, director of preventive medicine research at the Pennington Biomedical Research Center in Baton Rouge, says, "We know that one diet doesn't fit all. This style of caloric control may work for some people, but we need more research to test the proposed mechanisms and benefits."
The bigger question is whether people can stick with a fasting diet, given the amount of time and energy it takes, he says.
To learn about the science behind fasting, Mosley interviewed several researchers, including ones with the National Institute on Aging and at several major universities across the country. Much of the research on fasting has been done on rats and mice, but there have been 11 human trials on it, Mosley says.
Some of the medical benefits of fasting involve the hormone insulin-like growth factor 1, called IGF-1, Mosley says. People need adequate levels when they are young and growing, but high levels later in life appear to lead to accelerated aging and cancer, including breast cancer and prostate cancer, he says. Fasting appears to reduce the levels of IGF-1, and it appears to switch on a number of repair genes. The reason it happens is not fully understood, he says.
Mosley says fasting may also increase production of a brain-derived neurotropic factor that seems to improve mood and protect the brain against the ravages of dementia, Alzheimer's disease and age-related mental decline. "This is based on animal research, and they are doing human studies now."
Marji McCullough, a nutrition epidemiologist with the American Cancer Society, says, "Higher levels of IGF-1 have been linked to several cancers, including breast, prostate and colorectal cancer. Whether reducing IGF-1 levels will lower cancer risk is plausible but not proven."
The key for any diet is whether or not people can stick with it and keep the weight off, she says.
Mosley believes fasting has "undone" some of the damage he has done to his body over the years and hopes that it will help him live longer and healthier.
He recommends seeing your doctor before starting a fasting program. He says fasting is not recommended for people who are pregnant, those who are underweight, people with diabetes (especially type 1), and children and teenagers who aren't fully grown. And he wouldn't recommend it to people who have issues with food, although "there is no evidence it will trigger anorexia or bulimia," Mosley says.
Although plenty of people have reported their weight-loss success stories to him, not everyone is going to get the results they want, Mosley says. "No diet is going to agree with everyone. Some people find that they don't lose weight as fast as they thought. That's probably from overeating on the other five days. It's not magic."

SOURCE :  http://www.wltx.com/news/watercooler/article/228205/363/FastDiet-Book-Is-Attracting-Dieters-and-Doubters