The Obesity Code: Unlocking the Secrets of Weight Loss (Why Intermittent Fasting Is the Key to Controlling Your Weight)

by Jason Fung

the root cause of obesity is a complex hormonal imbalance with high blood insulin as its central feature. The hormonal profile of a baby is influenced by the environment in the mother’s body before birth, setting up a tendency for high insulin levels and associated obesity later in life.

The key assumption of the theory that reducing caloric intake leads to weight loss is false, since decreased caloric intake inevitably leads to decreased caloric expenditure.

Losing weight triggers two important responses. First, total energy expenditure is immediately and indefinitely reduced in order to conserve the available energy. Second, hormonal hunger signaling is immediately and indefinitely amplified in an effort to acquire more food. Weight loss results in increased hunger and decreased metabolism. This evolutionary survival strategy has a single purpose: to make us regain the lost weight.

There’s a dirty little secret that nobody is willing to admit: The low-fat, low-calorie diet has already been proven to fail. This is the cruel hoax. Eating less does not result in lasting weight loss. It. Just. Does. Not. Work.

But diet and exercise are not fifty-fifty partners like macaroni and cheese. Diet is Batman and exercise is Robin.

For every extra hour of exercise, the kids ate an extra 292 calories. Caloric intake and expenditure are intimately related: increasing one will cause an increase in the other. This is the biological principle of homeostasis. The body tries to maintain a stable state. Reducing Calories In reduces Calories Out. Increasing Calories Out increases Calories In.

Several hours after a meal, blood sugars and insulin levels start to drop. Less glucose is available for use by the muscles, the brain and other organs. The liver starts to break down glycogen into glucose to release it into general circulation for energy—the glycogen-storage process in reverse. This happens most nights, assuming you don’t eat at night.

In the type 1 diabetic community, there is a disorder called “diabulimia.” Today, type 1 diabetic patients are treated by daily injections of insulin. There are some patients who wish to lose weight for cosmetic reasons. Diabulimia is the deliberate under-dosing of insulin for the purpose of immediate and substantial weight loss. It is extremely dangerous and certainly not advisable. However, the practice persists is because it is an extremely effective form of weight loss. Insulin levels go down. Weight is lost.

THE RESULTS ARE very consistent. Drugs that raise insulin levels cause weight gain. Drugs that have no effect on insulin levels are weight neutral. Drugs that lower insulin levels cause weight loss.

The question is not how to balance calories; the question is how to balance our hormones. The most crucial question in obesity is how to reduce insulin.

Long-term stress leads to long-term elevated cortisol levels, which leads to extra pounds.

Total and percentage carbohydrate intake in China far exceeds the other nations. Sugar intake in China, however, is extremely low compared to the other nations. Japan’s carbohydrate intake is similar to that of the U.K. and the U.S., but its sugar consumption is far lower. Despite high carbohydrate intakes, obesity rates in China and Japan stayed very low until recently.

Insulin and obesity are still causally linked. However, it is not at all clear that high carbohydrate intake is always the primary cause of high insulin levels. In Kitava, high carbohydrate intake did not lead to elevated insulin. The notion that carbohydrates are the only driver of insulin is incorrect. A critical piece of the puzzle had been neglected. Specifically, sugar plays a crucial role in obesity, but how does it fit in? The missing link was insulin resistance.

When insulin (the key) no longer fits into the receptor (the lock), the cell is called insulin resistant. Because the fit is poor, the door does not open fully. As a result, less glucose enters. The cell senses that there is too little glucose inside. Instead, glucose is piling up outside the door. Starved for glucose, the cell demands more. To compensate, the body produces extra keys (insulin). The fit is still poor, but more doors are opened, allowing a normal amount of glucose to enter.

Exposure causes resistance. A biological system that becomes disturbed tries to go back to its original state. As we use an antibiotic more and more, organisms resistant to it are naturally selected to survive and reproduce. Eventually, these resistant organisms dominate, and the antibiotic becomes useless.

Insulin resistance requires persistently high levels. The nightly fasting caused periods of very low insulin, so resistance could not develop.

Pulses of insulin (mealtimes) are followed by a long fasting period (sleep), as illustrated in Figure 10.1. However, the situation changes entirely when we are constantly exposed to insulin. What would happen if daily eating opportunities are increased from three to six—which is exactly what’s happened since the 1970s.

But in the development of obesity, the increase in meals is almost twice as important as the change in diet.

Previously, all eating was done at mealtimes at a table. Now, it is acceptable to eat anywhere. We can eat in the car. We can eat in the movie theatre. We can eat in front of the TV. We can eat in front of the computer. We can eat while walking. We can eat while talking. We can eat in a box. We can eat with a fox. We can eat in a house. We can eat with a mouse. You get the picture.

Societal mechanism of where to eat changed when we eat!

But the obesity epidemic couldn’t very well be ignored, and a culprit had to be found. “Calories” was the perfect scapegoat. Eat fewer calories, they said. But eat more of everything else. There is no company that sells “Calories,” nor is there a brand called “Calories.” There is no food called “Calories.” Nameless and faceless, calories were the ideal stooge. “Calories” could now take all the blame.

It is simply not necessary to eat the minute we wake up. We imagine the need to “fuel up” for the day ahead. However, our body has already done that automatically. Every morning, just before we wake up, a natural circadian rhythm jolts our bodies with a heady mix of growth hormone, cortisol, epinephrine and norepinephrine (adrenalin). This cocktail stimulates the liver to make new glucose, essentially giving us a shot of the good stuff to wake us up. This effect is called the dawn phenomenon, and it has been well described for decades.

There are some commonsense questions you can ask yourself about breakfast. Are you hungry at breakfast? If not, listen to your body and don’t eat.

In 2011, the United States Public Interest Research Groups noted that “corn receives an astounding 29 percent of all U.S. agricultural subsidies, and wheat receives a further 12 percent.”7 Corn is processed into highly refined carbohydrates for consumption, including corn syrup, high-fructose corn syrup and cornstarch. Wheat is almost never consumed as a whole berry but further processed into flour and consumed in a wide variety of foods. Unprocessed carbohydrates, on the other hand, receive virtually no financial aid. While mass production of corn and wheat receives generous support, the same cannot be said for cabbage, broccoli, apples, strawberries, spinach, lettuce and blueberries.

The government is subsidizing, with our own tax dollars, the very foods that are making us obese. Obesity is effectively the result of government policy.

DURING THE YEARS 1977 to 2000, the prevalence of childhood obesity skyrocketed in every age category. Obesity in children aged six to eleven increased from 7 percent to 15.3 percent. For children aged twelve to nineteen, it more than tripled, from 5 percent to 15.5 percent.

What has really hampered our ability to combat childhood obesity, though, is a simple lack of understanding about the true causes of weight gain. A singular misguided focus on reducing caloric intake and increasing exercise led to government programs that have almost no chance of success. We didn’t lack resources or willpower; we lacked knowledge of and a framework for understanding obesity.

Reducing the use of sugar-sweetened beverages is a highly effective method of preventing childhood obesity.

From 2003 to 2013, soft-drink consumption in the United States dropped by close to 20 percent.2 Sweetened iced teas and sugary sports drinks have valiantly tried to take their place, but have been unable to block the winds of change. By 2014, Coca Cola had faced nine consecutive years of sales decline as health concerns about sugar mounted. Concerned with declining health and ballooning waistlines, people were less inclined to drink a toxic, sugary brew.

But the sugar pushers weren’t so easily defeated. Knowing that they were fighting a losing battle in much of North America and Europe, they took aim at Asia to make up for lost profits. Asian sugar consumption is rising at almost 5 percent per year,3 even as it has stabilized or fallen in North America. The result has been a diabetes catastrophe. In 2013, an estimated 11.6 percent of Chinese adults have type 2 diabetes, eclipsing even the long-time champion: the U.S., at 11.3 percent.

Fructose overconsumption leads directly to insulin resistance.

From humble beginnings in 1960 to the year 2000, the consumption of diet soda has increased by more than 400 percent. Diet Coke has long been the second most popular soft drink, just behind regular Coca Cola. In 2010, diet drinks made up 42 percent of Coca Cola’s sales in the United States. Despite initial enthusiasm, though, the use of artificial sweeteners has recently leveled off, primarily due to safety concerns.

Artificial sweeteners are not good. They are bad. Very bad.

Functional MRI studies show that glucose activates the brain’s reward centers fully—but not sucralose.16 The incomplete activation could stimulate cravings for sweet food to fully activate the reward centers.

Generally, the deciding factor is who paid for the study. Researchers looked at seventeen different reviews of sugar-sweetened drinks and weight gain.21 A full 83.3 percent of studies sponsored by food companies did not show a relationship between sugar-sweetened drinks and weight gain. But independently funded studies showed the exact opposite—83.3 percent showed a strong relationship between sugar-sweetened drinks and weight gain.

How we were duped for so long? Oh wait... everything we read was corrupted and wrong.

Insulin and insulin resistance drive obesity. Refined carbohydrates, such as white sugar and white flour, cause the greatest increase in insulin levels.

refining encourages overconsumption. For example, making a glass of orange juice may require four or five oranges. It is very easy to drink a glass of juice, but eating five oranges is not so easy. By removing everything other than the carbohydrate, we tend to overconsume what is left. If we had to eat all the fiber and bulk associated with five oranges, we might think twice about it. The same applies to grains and vegetables.

Processing methods have changed significantly over the centuries. Wheat berries were traditionally ground by large millstones powered by animals or humans. The modern flourmill has replaced traditional stone grinding. The bran, middlings, germ and oils are efficiently and completely removed, leaving the pure white starch. Most of the vitamins, proteins, fiber and fats are removed along with the outer hull and bran. The flour is ground to such a fine dust that its absorption by the intestine is extremely rapid. The increased rate of glucose absorption amplifies the insulin effect. Whole wheat and whole grain flours retain some of the bran and germ, but suffer from the same problem of rapid absorption.

FIBER IS THE non-digestible part of food, usually of a carbohydrate. Common types of fiber include cellulose, hemicellulose, pectins, beta-glucans, fructans and gums. Fiber is classified as soluble or insoluble based on whether it is dissolvable in water. Beans, oat bran, avocado and berries are good sources of soluble fiber. Whole grains, wheat germ, beans, flax seeds, leafy vegetables and nuts are good sources of insoluble fiber. Fiber can also classified as fermentable or non-fermentable.

In one study,21 type 2 diabetic patients were split into two groups and given standardized liquid meals, one control group and the other with added fiber. The group that received liquid meals with added fiber reduced both the glucose and the insulin peaks, despite the fact that the two groups consumed exactly the same amount of carbohydrates and calories. Because insulin is the main driver of obesity and diabetes, its reduction is beneficial. In essence, fiber acts as a sort of “antidote” to the carbohydrate—which, in this analogy, is the poison.

Fiber and fat, key ingredients, are removed in the refining process: fiber, to change the texture and make food taste “better,” and natural fats, to extend shelf life, since fats tend to go rancid with time. And so we ingest the “poison” without the “antidote”—the protective effects of fiber is removed from much of our food.

There are no long-term data on the use of vinegar for weight loss. However, smaller short-term human studies suggest that vinegar may help reduce insulin resistance.27 Two teaspoons of vinegar taken with a high-carbohydrate meal lowers blood sugar and insulin by as much as 34 percent, and taking it just before the meal was more effective than taking it five hours before meals.28

Milk contains two main types of dairy protein: casein (80 percent) and whey (20 percent). Cheese contains mostly casein. Whey is the byproduct left over from the curds in cheese making. Bodybuilders frequently use whey protein supplements because it is high in branched-chain amino acids, felt to be important in muscle formation.

Blood glucose accounts for only 23 percent of the insulin response. Dietary fats and protein only accounts for another 10 percent. Close to 67 percent of the insulin response is still unknown—which is tantalizingly close to the 70 percent contribution to obesity that is inherited, as described in chapter 2.

Simplistic arguments that “Carbs make you fat!” or “Calories make you fat!” or “Red meat makes you fat!” or “Sugar makes you fat!” do not fully capture the complexity of human obesity. The hormonal obesity theory provides a framework for understanding the interaction of disease. All foods stimulate insulin, thus all foods could be fattening—and that’s where the calorie confusion emerges. Since all foods could be fattening, we imagined that all foods could be measured in a common unit: the calorie. But the calorie was the wrong unit. Calories do not cause obesity. Instead, insulin is responsible. Without a framework for understanding insulin, it was impossible to understand the inconsistencies of the epidemiologic evidence. The low-fat caloric-reduction approach was a proven failure. The high-protein approach was subsequently proved a failure.

There are no intrinsically bad foods, only processed ones. The further you stray from real food, the more danger you are in. Should you eat protein bars? No. Should you eat meal replacements? No. Should you drink meal replacement shakes? Absolutely not. Should you eat processed meats, processed fats or processed carbohydrates? No, no and no.

There will be times when we’ll eat processed food because it is cheap, available and, let’s face it, delicious (think ice cream). However, we have, over the centuries, developed other dietary strategies such as fasting to detoxify or cleanse ourselves. These strategies have been lost in the mists of time.

This negative result would be repeatedly confirmed over the next half century. No matter how hard we looked,11 there was no discernible relationship between dietary fat and blood cholesterol. Some trials, such as the Puerto Rico Heart Health Program, were huge, boasting more than 10,000 patients. Other trials lasted more than twenty years. The results were always the same. Saturated-fat intake could not be linked to heart disease.

Even the National Cholesterol Education Program admits, “The percentage of total fat in the diet, independent of caloric intake, has not been documented to be related to body weight.”29 Translation: despite fifty years of trying to prove that dietary fat causes obesity, we still cannot find any evidence. This data is hard to find because it never existed.

The low-fat diet was a complete failure. The emperor had no clothes.

Dark chocolate with more than 70 percent cacao, in moderation, is a surprisingly healthy treat. The chocolate itself is made from cocoa beans and does not naturally contain sugar. (However, most milk chocolate does contain