About the Author
Dr. Michael Mosley is the author of The Clever Gut Diet, The 8-Week Blood Sugar Diet, and the coauthor, with Mimi Spencer, of the #1 New York Times bestseller The Fast Diet, which has been published in over thirty-two languages around the world. He is also coauthor, with Peta Bee, of Fast Exercise and wrote the foreword for The Fast Diet Cookbook by Mimi Spencer and Dr. Sarah Schenker. Dr. Mosley trained to be a doctor at the Royal Free Hospital in London before joining the BBC, where he has been a science journalist, executive producer, and, more recently, a well-known television personality. He has won numerous television awards, including an RTS (Royal Television Award), and was named Medical Journalist of the Year by the British Medical Association.
Excerpt. © Reprinted by permission. All rights reserved.
The 8-Week Blood Sugar Diet CHAPTER ONE
The Obesity Epidemic: Why We’re in the State We’re In
JON HAD A SERIOUS WEIGHT problem, but so, increasingly, does the rest of the world. And this has not crept up on us gradually. People became a bit heavier in the years after World War II, but obesity took off in a spectacular fashion at the beginning of the 1980s; in a single generation it swept the globe.
The fattest people on earth now live in places like Mexico, Egypt, and Saudi Arabia. Countries like China and Vietnam, though still relatively lean, have seen the numbers of overweight adults triple in less than forty years.
Among the rich, developed countries, it is the Americans, British, and Australians who currently lead the pack, with roughly two-thirds of their population overweight. Men and women in these countries have put on an average of 18 pounds (the equivalent of a large, heavy suitcase) in the last three decades, much of it around the belly area.
Children are particularly at risk. The only type of diabetes that used to be seen in children was type 1, where the immune system mistakenly attacks the cells responsible for blood sugar control. Now many more are coming into doctor’s offices with type 2, which is largely due to weight and lifestyle. In the United States, a three-year-old girl who weighed 77 pounds was recently in the news as one of the youngest type 2 diabetics yet seen.
A poor diet affects not just this generation but the next. Overweight mothers are having ever larger babies, who in turn are programmed by the rich diet they get in the womb to become obese in later life.
Obesity spreads like a virus, with family and friends being a major influence on what and how much we eat and what we consider “normal.” Being a bit on the chubby side is socially acceptable. There are size 16 models; muffin tops and double chins can be seen everywhere. But while the celebration of curviness has been, in many ways, a desirable response to unrealistically skinny supermodels, it remains a sad fact that too much fat in the wrong places has serious consequences.
So what triggered this explosion?
The obvious answer is that we eat more. In the United States, average calorie intake has increased by over 25 percent since the late 1970s, which would easily account for Americans’ weight gain.
But in that same period consumption of saturated fats, such as butter, actually fell. The really big surge, which began in 1980, was in carbohydrates, particularly refined grains, up by a whopping 20 percent in just fifteen years. A study published in the American Journal of Clinical Nutrition that compared what Americans have been eating for the last few decades with rates of diabetes could find no link between the disease and the amount of fat and protein consumed.3 Instead, the researchers blamed the rise of diabesity on falling levels of fiber in the diet, combined with a dramatic rise in the consumption of refined carbohydrates. And what almost everyone now acknowledges is that the rise in consumption of refined carbs came about as an unintended consequence of the war on fat.
The Rise and Rise of Carbohydrates
In 1955 President Eisenhower had a heart attack that nearly killed him. At that time heart disease in the United States was rampant, and so the hugely influential American Heart Association decided, on the basis of what turned out to be rather flimsy evidence, to declare war on saturated fat. Out with steak, butter, full-fat milk, and cheese; in with margarine, vegetable oils, bread, cereals, pasta, rice, and potatoes.
The man who convinced the American Heart Association, and then the rest of the world, to pursue this path was a physiologist named Ancel Keys. In the 1950s he did a study that compared fat consumption and deaths from heart disease in men from six different countries.
He showed that men in the United States, who got a lot of their calories from fat, were far more likely to die from heart disease than men in Japan, who ate little fat. The link seemed clear and compelling. The fact that the Japanese also ate far less sugar and processed foods was discounted. The fact that some countries, such as France, enjoy high rates of fat consumption and yet have low levels of heart disease was dismissed as an anomaly.
The American Heart Association gave Keys its support, and the anti-fat campaign began in earnest. It took a while to get going, but by the 1980s there was a dramatic change in what people were eating all around the world. Huge numbers followed medical advice and switched from eating animal fats, like butter and milk, to eating margarine, low-fat products, and vegetable oils.
The campaign against saturated fat was not just based on fear that it would clog up arteries. Eating fat, it was widely believed, made you fat. Ounce for ounce, fat contains more calories than either carbohydrates or protein. So the easiest way to lose weight, it was thought, was to cut down on fat.
Low-fat diets were created and endorsed enthusiastically by the medical profession. My father tried quite a few and lost weight on each. The trouble was, he found them impossible to stick to. He was not alone. The success rate of low-fat diets, even where patients are highly motivated and closely supervised, has been poor.
A poignant example of this was the Look Ahead trial in 2001.4 Sixteen medical centers in the United States recruited more than five thousand overweight diabetics to take part in a randomized, controlled trial. Half were offered standard care; the other half were put on a low-fat diet. The low-fat group got personal nutritionists, trainers, group support sessions—the best that money could buy.
The trial was due to run until 2016, but it was stopped after ten years because the patients in the low-fat group had lost only a little more weight than the control group and there were no differences in rates of heart disease or stroke. The diabetic patients had managed to cut their fat consumption, but that had not produced either the weight loss or the health benefits that were hoped for.
In the meantime, the campaign against fat was working very successfully, in the sense that the world now ate far more fat-free and reduced-fat “diet” products. But we didn’t get slimmer; we became fatter.
Part of the problem was that food manufacturers, when they took out the fat, put in sugar to make their food more palatable. The low-fat Starbucks muffin, for instance (now discontinued, or at least I can no longer find it on the Starbucks website), used to contain 430 calories and the equivalent of 13 teaspoons of sugar. People seemed to think that if a product said “fat-free” on the label, then it wouldn’t make you fat. There were doctors telling the public that you can’t get fat eating carbohydrates; one leading nutritional expert, Jean Mayer, said that prescribing a carbohydrate-restricted diet to the public was “the equivalent of mass murder.”
I started medical school in 1980, when the campaign against fat was in full flow. I gave up butter, cream, and eggs. I rarely ate red meat and switched to skim milk and low-fat yogurt, neither of which I enjoyed, but both of which I was sure were good for me. Over the next few decades, despite much self-denial, I put on nearly 30 pounds and my blood sugar soared. The high-carb, low-fat diet I was on wasn’t making me healthier. It was doing the reverse.
Carbs and Insulin
Well, the thing about carbs, particularly the easily digestible ones, such as sugar, but also breakfast cereals, pasta, bread, and potatoes, is that they are easily broken down in the gut to release sugar into your system.
Your pancreas responds by producing insulin. One of insulin’s main jobs is to bring high blood sugar levels down, and it does this by helping energy-hungry cells, such as those in your muscles, take up the sugar.
Unfortunately, an unhealthful diet and a low-activity lifestyle can, over many years, lead to what’s called insulin resistance. Your body becomes less and less sensitive to insulin. Your blood sugar levels creep up. And as they rise, your pancreas responds by pumping out more and more insulin. But it’s like shouting at your kids—after a while they stop listening.
While your muscles are becoming insulin-resistant, however, insulin is still able to force surplus calories into your fat cells. The result is that as your insulin levels rise, more and more energy is diverted into fat storage. The higher your insulin levels, the fatter you get.
And yet the more calories you tuck away as fat, the less you have to keep the rest of your body going. It’s a bit like buying fuel, but instead of putting it in the gas tank you put it in the trunk of the car. The fuel gauge sinks, but your frantic attempts to top up fail because the fuel is going into the wrong place. Similarly, your muscles, deprived of fuel, tell your brain to eat more. So you do. But because your high insulin levels are encouraging fat storage, you just get fatter while staying hungry.
Dr. Robert Lustig, a renowned pediatric endocrinologist who has treated hundreds of overweight children, points out in his excellent book Fat Chance that understanding insulin is crucial to understanding obesity. “There is no fat accumulation without the energy-storage hormone, insulin,” he writes. “Insulin shunts sugar to fat. It makes your fat cells grow. The more insulin the more the fat.”
He argues that the main reason obesity levels have doubled over the last thirty years is because our bodies are producing far more insulin than ever before. And he blames the modern diet, rich in sugar and refined carbs, for pumping up our insulin levels, a claim supported by many other leading obesity experts, including Dr. David Ludwig, a pediatrician at Harvard Medical School, and Dr. Mark Friedman, head of the Nutrition Science Initiative in San Diego. They recently wrote an opinion piece in the New York Times (“Always Hungry? Here’s Why”) in which they point the finger firmly at refined carbs: “The increasing amount and processing of carbohydrates in the American diet has increased insulin levels, put fat cells into storage overdrive and elicited obesity-promoting biological responses in a large number of people. High consumption of refined carbohydrates—chips, crackers, cakes, soft drinks, sugary breakfast cereals and even white rice and bread—has increased body weights throughout the population.”5
Dr. Ludwig is worth listening to because for many years he has run one of the largest clinics for overweight children in the United States at the Boston Children’s Hospital. He has seen close up how easily digestible carbs (those with a high glycemic load; see page 72) have been a major driver of obesity.
In one study, he took twelve overweight teenage boys and on separate days gave them three different breakfasts.6 One was instant oatmeal with milk and sugar. Another was traditional, unprocessed steel-cut oats—the sort your grandmother would recognize. The third breakfast was an omelet.
The worst breakfast was the instant oats. After eating it, the boys’ blood sugar and insulin levels soared, followed a couple of hours later by a crash as blood sugar levels fell below where they had started. This crash was accompanied by a surge of the stress hormone adrenaline. The boys felt tired, hungry, and irritable. At lunch they each ate a whopping 620 calories more than those who had had the omelet.
From personal experience I know how this feels. If I eat toast or cereal, I get hungry by midmorning. But if I eat, say, scrambled eggs for breakfast (even if it’s the same number of calories), they keep me going well into the afternoon.
In another study, Ludwig put twenty-one overweight young men on diets ranging from low-fat to low-carb.7 Despite eating exactly the same number of calories, those on the low-carb diet burned 325 calories more per day than those on the low-fat diet. This is about as much energy as you would burn in forty minutes of jogging.
“By the Time You Are Fifty, You Are Going to Have the Body You Deserve”
This is what Bob Smietana used to eat:
Breakfast: cereal, muffins, coffee (several cups)
Lunch: hamburger, pizza, french fries, soda
Dinner (on the way home in the car): two double cheeseburgers, big fries, soda
This fatty, carb-driven diet is typical of what many people eat on a regular basis. It’s not as though we don’t know those big bags of chocolate are supposed to be for sharing, or that that blueberry muffin won’t count as one of our five daily servings of fruits and vegetables. It’s just that this kind of stuff is so much easier to eat . . . even if it does leave us feeling bloated one second and starving the next.
Smietana is a journalist based in Chicago. He is an articulate, self-deprecating, middle-class kind of guy, with two teenage children, a happy marriage, and a successful career. During the time when he was on calorie overload, he had a lot on his plate, metaphorically speaking—his work was stressful, and he was worried about his wife, who had been ill. Carb-filled, convenient fast food was a comfort.
Except it wasn’t, because he was bad-tempered all the time, which wasn’t like him. “I called myself ‘Angry Bob,’ ” he says, looking back. “I was irritated constantly. Frustrated. Little things would set me off. My tension level had grown over time.” He wasn’t sleeping well, he says, and “I was making mistakes at work. My thinking wasn’t clear.” Sleep problems and mental fuzziness are both symptoms of blood sugar issues, but most people don’t make the connection.
He was in his midforties. He weighed over 280 pounds (he doesn’t know for sure, because after that point he refused to get on the scale). And he didn’t like what he could see in the mirror. Not long after this, he was diagnosed with type 2 diabetes.
“The minute the diagnosis came, it was terrifying,” recalls Smietana. He describes it now as a teachable moment. “I wanted to live to see my daughter get married. I wanted to be around to enjoy my grandchildren. But I knew I was walking slowly toward an early death.
“Changing your diet and your habits is such a huge thing,” he says. “You think, ‘I can’t do that.’ You can’t get started because you think it is too hard. The mountain is too big.”
How did he do it? “Bit by bit. By moving in that direction and not thinking too much about how big this was. But it started with my own fear. The fear was a strength.”
The first thing he did was get rid of the unhealthful carbohydrates. The second thing he did was eat more vegetables. His calorie intake plummeted. “The more I did it, the less I liked the wrong things.” He lost 90 pounds.
The man who used to be a regular at his local McDonald’s drive-through took up walking. “I will go for a walk now. Even if the world is on fire, I will go for a walk, because I know that is what I need to do.” His next goal is to run a marathon.
“I am a great believer in habit,” says Smietana. “Once you do something over and over again, it becomes automatic and you stop thinking about it.” He eats at the same time every day, he eats the same things, and he walks at the same time every day.
Looking back at how he used to live, he thinks we’ve become disconnected from our bodies. “We are on the phone or living virtual lives. We don’t think about the physical side of life. We don’t understand how our bodies work. Most people don’t know what their pancreas does. What insulin is.” Now he can tell when his ...
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