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

by Jason Fung

THE MAJORITY OF Americans identify breakfast as the most important meal of the day. Eating a hearty breakfast is considered a cornerstone of a healthy diet. Skipping it, we are told, will make us ravenously hungry and prone to overeat for the rest of the day. Although we think it’s a universal truth, it’s really only a North American custom. Many people in France (a famously skinny nation) drink coffee in the morning and skip breakfast. The French term for breakfast, petit déjeuner (little lunch) implicitly acknowledges that this meal should be kept small. The National Weight Control Registry was established in 1994 and monitors people who have maintained a weight loss of 30 pounds (14 kilograms) for more than one year. The majority (78 percent) of the National Weight Control Registry participants eat breakfast.7 This, we are told, is proof that eating breakfast aids weight loss. But what percentage of those who did not lose weight ate breakfast? Without knowing, it’s impossible to draw any firm conclusions. What if 78 percent of those that did not lose weight also ate breakfast? This data is not available. Furthermore, the National Weight Control Registry itself is a highly self-selected population8 and not representative of the general population. For example, 77 percent of registrants are women, 82 percent are college educated and 95 percent are Caucasian. Furthermore, an association (for instance, between weight loss and eating breakfast) does not mean causality. A 201...

In 2014, researchers gathered all available studies on increased intake of fruit-and-vegetable and weight loss.15 They could not find a single study to support this hypothesis. Combining all the studies did not show any weight-loss benefit either. To put it simply, you cannot eat more to weigh less, even if the food you’re eating more of is as healthy as vegetables. So should we eat more fruits and vegetables? Yes, definitely. But only if they are replacing other unhealthier foods in your diet. Replace. Not add.16

EXCESSIVELY HIGH INSULIN resistance is the disease known as type 2 diabetes. High insulin resistance leads to elevated blood sugars, which are a symptom of this disease. In practical terms, this means that not only does insulin causes obesity, but also that insulin causes type 2 diabetes. The common root cause of both diseases is high, persistent insulin levels. Both are diseases of hyper-insulinemia (high insulin levels). Because they are so similar, both diseases are beginning to be observed as a syndrome, aptly termed diabesity. That high insulin levels cause both obesity and type 2 diabetes has profound implications. The treatment for both is to lower insulin levels, yet current treatments focus on increasing insulin levels, which is exactly wrong. Giving insulin for type 2 diabetes will worsen, not improve, the disease. But can lowering insulin levels cure type 2 diabetes? Absolutely. But the many misunderstandings about type 2 diabetes would require another book to clarify.

Our own disastrous, misguided dietary changes since the 1970s have created the diabesity debacle. We have seen the enemy, and it is ourselves. Eat more carbohydrates. Eat more often. Eat breakfast. Eat more. Ironically, these dietary changes were prescribed to reduce heart disease, but instead, we’ve encouraged it since diabesity is one of the strongest risk factors for heart disease and stroke. We’ve been trying to put out a fire with gasoline.

Socioeconomic status has long been known to play a role in the development of obesity in that poverty correlates very closely with obesity.

But the association of obesity with poverty presents a problem. The food-reward hypothesis would predict that obesity should be more prevalent among the rich, since they can afford to buy more of the highly rewarding foods. But the exact opposite is true. Lower-income groups suffer more obesity. To be blunt, the rich can afford to buy food that is both rewarding and expensive, whereas the poor can afford only rewarding food that is cheaper. Steak and lobster are highly rewarding—and expensive—foods. Restaurant meals, which are expensive compared to home cooking, are also highly rewarding. Increased prosperity results in increased access to different types of highly rewarding food, which should result in more obesity. But it does not.

The majority of exercise is free, often requiring no more than a basic shoe. Walking, running, soccer, basketball, push-ups, sit-ups and calisthenics all require minimal or no cost, and they are all excellent forms of exercise. Many occupations, such as construction or farming, involve significant physical exertion throughout the working day. Those jobs require heavy lifting, day after day after day. Contrast that to an office-bound lawyer or a Wall Street investment banker. Spending up to twelve hours a day perched in front of a computer, his or her physical exertion is limited to walking from desk to elevator. Despite this large difference in daily physical activity, obesity rates are higher in the less affluent but more physically active group.

Neither food reward nor physical exertion can explain the association between obesity and poverty. So what drives obesity in the poor? It is the same thing that drives obesity everywhere else: refined carbohydrates. For those dealing with poverty, food needs to be affordable. Some dietary fats are fairly inexpensive. However, we do not, as a general rule, drink a cup of vegetable oil for dinner. Furthermore, official government recommendations are to follow a low-fat diet. Dietary proteins, such as meat and dairy, tend to be relatively expensive. Less expensive vegetable proteins, such as tofu or legumes, are available but not typical in a North American diet. This leaves carbohydrates. If refined carbohydrates are significantly cheaper than other sources of food, then those living in poverty will eat refined carbohydrates. Indeed, processed carbohydrates are entire orders of magnitude less expensive. An entire loaf of bread might cost $1.99. An entire package of pasta might cost $0.99. Compare that to cheese or steak, which might cost $10 or $20. Unrefined carbohydrates, such as fresh fruits and vegetables, cannot compare to the low, low prices of processed foods. A single pound of cherries, for instance, may cost $6.99. Why are highly refined carbohydrates so cheap? Why are unprocessed carbohydrates so much more expensive? The government lowers the cost of production with hefty agricultural subsidies. But not all foods get equal treatment.