The Obesity Code Cookbook. Jason Fung

know how to treat the obe-

      sity. Despite having worked for more than ten years in medicine, I found

      that my nutritional knowledge was rudimentary, at best. This realization

      sparked a decade-long odyssey and eventually led me to establish the

      Intensive Dietary Management (IDM) program (www.IDMprogram.com)

      and the Toronto Metabolic Clinic (www.torontometabolicclinic.com).

      Obesity

      Medical Treatment

      Metabolic Syndrome

      Type 2 Diabetes

      Heart Attacks

      Stroke

      Cancer

      Kidney Disease

      Blindness

      Amputation

      Nerve Damage

      ( 13 )

      introduction

      Thinking seriously about the treatment of obesity, I realized there

      was one singularly important question to understand: What causes

      weight gain? That is, what is the root cause of weight gain and obesity?

      The reason we never think about this crucial question is that we think

      we already know the answer. We think that eating too many calories

      causes obesity. If this were true, then the solution to weight loss would

      be simple: Eat fewer calories.

      Figure 2: A More Effective Paradigm of Medical Treatment

      But we’ve done that already. Ad nauseam. For the last forty years, the

      only weight-loss advice has been to cut your calories and exercise more.

      This is the highly ineffective strategy called Eat Less, Move More. We

      have calorie counts on every food label. We have calorie-counting books.

      We have calorie-counting apps. We have calorie counters on our exercise

      machines. We’ve done everything humanly possible to count calories so

      that we could cut them. Has it worked? Have those pounds melted like a

      snowman in July? No. It sure sounds like it should work. But the empir-

      ical evidence, plain as a mole on the tip of your nose, is that it does not

      work.

      From a human physiology standpoint, the entire calorie story col-

      lapses like a house of cards when you look closely at it. The body does

      not respond to “calories.” There are no calorie receptors on cell surfaces.

      The body has no ability to know how many calories you are eating or

      Obesity

      Medical

      Treatment

      Metabolic Syndrome

      Type 2 Diabetes

      Heart Attacks

      Stroke

      Cancer

      Kidney Disease

      Blindness

      Amputation

      Nerve Damage

      ( 14 )

      THE OBESITY CODE COOKBOOK

      not eating. If your body doesn’t count calories, why should you? A calo-

      rie is purely a unit of energy borrowed from physics. The field of obesity

      medicine, desperate for some simple measure of food energy, completely

      ignored human physiology and turned to physics instead.

      “A calorie is a calorie” soon became the statement du jour. It also gave

      rise to a question: Are all calories of food energy equally fattening? The

      answer to that is an emphatic no. One hundred calories of kale salad are

      not as fattening as one hundred calories of candy. One hundred calories

      of beans are not as fattening as one hundred calories of white bread and

      jam. But for the last forty years, we have believed that all calories are

      equally fattening.

      And that’s why I wrote The Obesity Code. In that book, I drew on what

      I learned over ten years of helping thousands of patients lose weight

      through my Intensive Dietary Management program. Nutrition is the

      key to metabolism, the process of breaking down food molecules to

      provide energy (calories) for the body and using that energy to build,

      maintain, and repair body tissues and allow the body to function effi-

      ciently. To answer the all-important question—what are the underlying

      causes of weight gain?—I started at the beginning, unraveled the calories

      model, and explained what’s really going on: Obesity is a hormonal, not

      a caloric, imbalance. And what we eat and when we eat are two major

      influences on our ability to manage weight gain and weight loss.

      Insulin

      In our body, nothing happens by accident. Every single physiological

      process is a tight orchestration of hormonal signals. Whether our heart

      beats faster or slower is tightly controlled by hormones. Whether we

      urinate a lot or a little is tightly controlled by hormones. Whether the

      calories we eat are burned as energy or stored as body fat is also tightly

      controlled by hormones. So, the main problem in terms of obesity is not

      the number of calories we eat, but how they are spent. And the main

      hormone we need to know about is insulin.

      ( 15 )

      introduction

      Insulin is a fat-storing hormone. There’s nothing wrong with that—

      that’s simply its job. When we eat, insulin production goes up, signaling

      the body to store some food energy as body fat. When we don’t eat, insu-

      lin production goes down, signaling the body to burn the stored energy

      (body fat). Higher-than-usual insulin levels tell our body to store more

      food energy as body fat.

      Everything about human metabolism, including body weight,

      depends upon hormonal signaling. A critical physiological variable such

      as body fatness is not left up to the vagaries of daily caloric intake and

      exercise. If early humans were too fat, they could not easily run and

      catch prey,