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

by Jason Fung

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. Federal subsidies encourage the cultivation of large amounts of corn and wheat, which are processed into many foods.

These foods, in turn, become far more affordable, which encourages their consumption. Large-scale consumption of highly processed carbohydrates leads to obesity. More tax dollars are then needed to support anti-obesity programs. Even more doll...

Was this a giant conspiracy to keep us sick? Doubtful. The large subsidies were simply the result of programs to make food affordable, which began in earnest in the 1970s. Back then, the major health concern was not obesity, but the “epidemic” of heart disease that was believed to be the result of excess dietary fat. The base of the Food Pyramid, the foods to be eaten by each of us every day, was bread, pasta, potatoes and rice. Naturally, money flowed into subsidies for those foods, the production of which was encouraged by t...

THE WORST OFFENDER, by far, is the sugar-sweetened drink—soft drinks, sodas and, more recently, sweetened teas and juices. Soda is a $75 billion industry

When these carbohydrates contain a single sugar (monosaccharides) or two sugars (disaccharides), they are called simple carbohydrates. When many hundreds or even thousands of sugars are linked into long chains (polysaccharides), they are called complex carbohydrates.

Sucrose was processed from sugar cane and sugar beets. While not exactly expensive, it wasn’t exactly cheap. High-fructose corn syrup, however, could be processed from the river of cheap corn that was flowing out of the American midwest—and that was the decisive factor in favor of high-fructose corn syrup. It was cheap.

Whereas almost every cell in the body can use glucose for energy, no cell has the ability to use fructose. Where glucose requires insulin for maximal absorption, fructose does not. Once inside the body, only the liver can metabolize fructose. Where glucose can be dispersed throughout the body for use as energy, fructose is targeted like a guided missile to the liver.

Excessive fructose puts significant pressure on the liver since other organs cannot help. It is the difference between pressing down with a hammer and pressing down with a needlepoint: much less pressure is needed if it is all directed onto a single point. At the liver, fructose is rapidly metabolized into glucose, lactose and glycogen. The body handles excess glucose consumption through several well-defined metabolic pathways, such as glycogen storage and de novo lipogenesis (creation of new fat). No such system is present for fructose. The more you eat, the more you metabolize. The bottom line is that excess fructose is changed into fat in the liver. High levels of fructose will cause fatty liver. Fatty liver is absolutely crucial to the development of insulin resistance in the liver.

In the short term, glucose is stored as glycogen in the liver, but the liver’s storage space for glycogen is limited. Once it’s full, excess glucose is stored as fat: that is, the liver begins manufacturing fat from glucose through de novo lipogenesis. After the meal, as insulin levels fall, this process reverses. With no food energy coming in, stored food energy must be retrieved. Glycogen and fat stores in the liver are turned back into glucose and distributed to the rest of the body for energy. The liver acts like a balloon. As energy comes in, it fills up. As energy is needed, it deflates. Balancing feeding and fasting periods over a day ensures that no net fat is gained or lost.

Artificial sweeteners may also cause harm by increasing cravings. The brain may perceive an incomplete sense of reward by sensing sweetness without calories, which may then cause overcompensation and increased appetite and cravings.15 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. In other words, you may be developing a habit of eating sweet foods, leading to overeating. Indeed, most controlled trials show that there is no reduction in caloric intake with the use of artificial sweeteners.17

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.

Carbohydrates are not inherently fattening. Their toxicity lies in the way they are processed.

Refining significantly increases the glycemic index by purifying and concentrating the carbohydrate. Removal of fat, fiber and protein means that the carbohydrate can be digested and absorbed

very quickly.

Starches are hundreds of sugars all linked together.

Wheat is converted to glucose more efficiently than virtually any other starch.

THE BENEFITS OF FIBER 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 dis-solvable 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.

Normal bacteria residing in the large intestine have the ability to ferment certain undigested fiber into the short-chain fatty acids acetate, butyrate and propi...

Generally, soluble fiber is more fermentable than insoluble.

Horace Fletcher (1849–1919) believed strongly that chewing every bite of food 100 times would cure obesity and increase muscle strength. Doing so helped him lose 40 pounds (18 kilograms), and “Fletcherizing” became a popular weight-loss method in the early twentieth century.

Fiber intake has fallen considerably over the centuries. In Paleolithic diets, it was estimated to be 77 to 120 grams per day.8 Traditional diets are estimated to have 50 grams per day of dietary fiber.9 By contrast, modern American diets contain as little as 15 grams per day.10 Indeed, even the American Heart Association’s Dietary Guidelines for Healthy North American Adults only recommends 25 to 30 grams per day.11

However, removal of dietary fiber is a key component of food processing. And improving the texture, taste and consumption of foods directly increases food companies’ profits.

Short-term studies show that fiber increases satiety, reduces hunger and decreases caloric intake.20

The key to understanding fiber’s effect is to realize that it is not as a nutrient, but as an anti-nutrient—where its benefit lies. Fiber has the ability to reduce absorption and digestion. Fiber subtracts rather than adds. In the case of sugars and insulin, this is good. Soluble fiber reduces carbohydrate absorption, which in turn reduces blood glucose and insulin levels.

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.

Eating pure carbohydrate does not activate these systems and leads to overconsumption (the second-stomach phenomenon).

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

Certain nutrients are considered essential in our diet because our bodies cannot synthesize them. Without dietary sources of these nutrients, we suffer ill health. There are essential fatty acids, such as the omega 3 and omega 6 fats, and essential amino acids, such as phenylalanine, valine and threonine. But there are no essential carbohydrates and no essential sugars. Those are not required for survival.

The insulin index, created by Susanne Holt in 1997, measures the rise in insulin in response to a standard portion of food, and it turns out to be quite different from the glycemic index.2

The cephalic phase is another pathway of insulin secretion independent of glucose. The body anticipates food as soon as it goes in your mouth and long before nutrients hit the stomach. For example, swishing a sucrose or saccharin solution around your mouth and spitting it out will increase your insulin level.7 While the importance of the cephalic phase is unknown, it highlights the significant fact that there are multiple glucose-independent pathways of insulin release.

Figure 17.2. The hormonal obesity theory. Animal protein is highly variable but comes with the protective effect of satiety. And we shouldn’t ignore the protective power of the incretin effect.

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.

SATURATED FATS ARE SO named because they are saturated with hydrogen. This makes them chemically stable. The polyunsaturated fats, like most vegetable oils, have “holes” where the hydrogen is “missing.” They are less stable chemically, so they have a tendency to go rancid and have a short shelf life. The solution was to create artificial trans fats.

In 1902, Wilhelm Normann discovered that you could bubble hydrogen into vegetable oil to saturate it, turning polyunsaturated fat into saturated fat. Food labels often called this partially hydrogenated vegetable oil. Trans fat is less likely to go rancid. Trans fats are semisolid at room temperature, so they spread easily and have an improved mouth feel. Trans fats were ideal for deep-frying. You can use this stuff over and over without changing it.

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 large amounts of sugar.) Dark and semisweet chocolate contain less sugar than milk or white varieties. Dark chocolate also contains significant amounts of fiber and antioxidants such as polyphenols and flavanols. Studies on dark-chocolate consumption indicate that it may help reduce blood pressure,5 insulin resistance6 and heart disease.7 Most milk chocolates, by contrast, are little more than candies. The cacao component is too small to be beneficial.

That is not to say that sugar cannot be an occasional indulgence. Food has always played a major role in celebrations—birthdays, weddings, graduations, Christmas, Thanksgiving, etc. The key word here is occasional. Dessert is not to be taken every day.

Be aware, though, that if your goal is weight loss, your first major step must be to severely restrict sugar. Don’t replace sugar with artificial sweeteners, as they also raise insulin as much as sugar and are equally prone to causing obesity. (See chapter 15.)

Oatmeal is another traditional and healthy food. Whole oats and steel-cut oats are a good choice, requiring long cooking times because they contain significant amounts of fiber that requires heat and time to break down. Avoid instant oatmeal. It is heavily processed and refined, which allows for instant cooking, and it contains large amounts of added sugar and flavors.

In thinking about what to eat for breakfast, consider this: If you are not hungry, don’t eat anything at all. It’s perfectly acceptable to break your fast at noon with grilled salmon and a side salad. But there’s nothing inherently wrong with eating breakfast in the morning either. It is just like any other meal. However, in the morning rush, many people tend to reach for conveniently prepackaged, heavily processed and heavily sugared foods. Eat whole, unprocessed foods at all meals, including breakfast. And if you don’t have time to eat? Then don’t eat. Again, simplify your life.

In choosing fats, strive for a higher proportion of natural fats. Natural, unprocessed fats include olive oil, butter, coconut oil, beef tallow and leaf lard. The highly processed vegetable oils, high in inflammatory omega 6 fatty acids, may have some detrimental health effects.

THERE ARE FIVE basic steps in weight loss: 1. Reduce your consumption of added sugars. 2. Reduce your consumption of refined grains. 3. Moderate your protein intake. 4. Increase your consumption of natural fats. 5. Increase your consumption of fiber and vinegar.

There is far more agreement than discord. Eliminate sugars and refined grains. Eat more fiber. Eat vegetables. Eat organic. Eat more home-cooked meals. Avoid fast food. Eat whole unprocessed foods. Avoid artificial colors and flavors. Avoid processed or microwavable foods. Whether you follow the low carb, low calorie, South Beach, Atkins or some other mainstream diet, the advice is very similar.

There is nothing new, except what has been forgotten. MARIE ANTOINETE

Hippocrates wrote, “To eat when you are sick, is to feed your illness.”

The ancient Greeks believed that fasting improved cognitive abilities. Think about the last time you ate a huge Thanksgiving meal. Did you feel more energetic and mentally alert afterward? Or instead, did you feel sleepy and a little dopey? More likely the latter. Blood is shunted to your digestive system to cope with the huge influx of food, leaving less blood for brain function. Fasting does the opposite, leaving more blood for your brain.

Paracelsus (1493–1541), the founder of toxicology and one of the three fathers of modern Western medicine (along with Hippocrates and Galen), wrote, “Fasting is the greatest remedy—the physician within.”

The practice of fasting developed independently among different religions and cultures, not as something that was harmful, but something that was deeply, intrinsically beneficial to the human body and spirit.1

GLUCOSE AND FAT are the body’s main sources of energy. When glucose is not available, then the body adjusts by using fat, without any health detriment. This compensation is a natural part of life. Periodic food scarcity has always been part of human history, and our bodies have evolved processes to deal with this fact of Paleolithic life. The transition from the fed state to the fasted state occurs in several stages:3