The Diabetes Code. Dr. Jason Fung
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of our shiny new advice to reduce fat and calories: first, perhaps this advice is good but people are simply not following it; second, perhaps the advice is simply wrong.
The idea that the spirit is willing but the flesh is weak—that people have the dream but not the drive—is as absurd as expecting a drowning man to laugh.
Was the entire obesity epidemic simply a sudden, simultaneous, coordinated, worldwide lack of willpower? The world can’t agree which side of the road we should drive on, yet, without discussion, we all decided to eat more and move less so that we could become undesirably fat? This explanation is only the latest iteration of the game called “blame the victim.” It shifts the responsibility from the advice giver (the advice is bad) to the advice taker (the advice is good, but you are not following it).
By declaring that their scientifically unproven caloric reduction advice was flawless, doctors and nutritionists could conveniently shift the blame from themselves to you. It wasn’t their fault. It was yours. Their advice was good. You didn’t follow it. No wonder they love this game so much. To admit that all their precious theories of obesity were simply incorrect was too psychologically difficult. Yet evidence continued to accumulate that this new caloric restriction strategy was about as useful as a comb to a bald man.
The Women’s Health Initiative25 was the most ambitious, important nutrition study ever done. This randomized trial involving almost 50,000 women evaluated the low-fat, low-calorie approach to weight loss. Although it was not specifically a weight-loss trial, one group of women was encouraged through intensive counseling to reduce their daily caloric intake by 342 calories and to increase their level of exercise by 10 percent. These calorie counters expected a weight loss of 32 pounds every single year.
When the final results were tallied in 1997, there was only crushing disappointment. Despite good compliance, more than seven years of calorie counting had led to virtually no weight loss. Not even a single pound. This study was a stunning and severe rebuke to the caloric theory of obesity. Reducing calories did not lead to weight loss.
There were now two choices. First, we could respect the expensive, hard-won, scientific evidence to devise a robust, more correct theory of obesity. Or we could simply keep all our comfortable and convenient preconceived notions and biases and ignore the science. The second choice involved far less work and far less imagination. So this ground-breaking study has largely been ignored and relegated to the dustbins of nutritional history. We have been paying the pied piper every day since, as the twin epidemics of obesity and type 2 diabetes have exploded.
Real-world studies26 have only confirmed this stunning fiasco. The conventional weight-loss advice to eat fewer calories carries an estimated failure rate of 99.4 percent. For morbid obesity, the failure rate is 99.9 percent. These statistics would not surprise anybody in the diet industry or, for that matter, anybody who has ever tried to lose weight.
The Calories-In, Calories-Out theory gained widespread acceptance based on its seemingly intuitive truth. However, like a rotting melon, digging past the outer shell revealed the putrid interior. This simplistic formula is riddled with erroneous assumptions. The most important error is believing that basal metabolic rate, or Calories Out, always remains stable. But a 40-percent reduction in calorie intake is quickly met with a 40-percent decrease in basal metabolic rate. The net result is no weight loss.
The other major false assumption is that weight is consciously regulated. But no system in our body functions like that. The thyroid, parathyroid, sympathetic, parasympathetic, respiratory, circulatory, hepatic, renal, gastrointestinal, and adrenal systems are all closely controlled by hormones. Body weight and body fat are also strictly regulated by hormones. In fact, our bodies contain multiple overlapping systems of body weight control. Body fat, one of the most important determinants of survival in the wild, is simply not left to the vagaries of what we decide to put in our mouths.
HORMONES: FOOD, BODY WEIGHT, AND DIABETES
HORMONES CONTROL HUNGER, telling our body when to eat and when to stop. Ghrelin is a powerful hormone that causes hunger, and cholecystokinin and peptide YY are hormones that tell us when we are full and should stop eating. Imagine you’re at an all-you-can-eat buffet. You’ve already eaten many heaping platefuls of food and you are completely, 110-percent full.
Now, could you eat a few more pork chops? Merely the thought might make you nauseous. Yet these are the same pork chops you ate happily just a few minutes ago. The difference is that satiety hormones are exerting a powerful effect to stop you from eating. Contrary to many popular beliefs, we do not continue eating simply because food is available. Calorie consumption is under tight hormonal regulation.
Fat accumulation is truly not a problem of energy excess. It’s a problem of energy distribution. Too much energy is diverted to producing fat as opposed to, say, increasing body heat or forming new bone tissue. This energy expenditure is controlled hormonally. As long as we believed, wrongly, that excessive caloric intake led to obesity, we were doomed to failure as we uselessly tried to reduce calories.
We cannot “decide” to feel less hungry. We cannot “decide” to increase basal metabolic rate. If we eat fewer calories, our body simply compensates by decreasing its metabolic rate. If calories are not the underlying cause of weight gain, then reducing calories cannot reliably reduce weight. The most important factor in controlling fat accumulation and weight gain is to control the hormonal signals we receive from food, not the total number of calories we eat.
Obesity is a hormonal imbalance, not a caloric one. The hormonal problem in undesired weight gain is mainly excessive insulin. Thus, type 2 diabetes, too, is a disease about insulin imbalance rather than caloric imbalance.
THE ROLE OF INSULIN IN ENERGY STORAGE
HERE’S A STARTLING fact: I can make you fat. Actually, I can make anybody fat. How? It’s really quite simple. I prescribe insulin. Although insulin is a natural hormone, excessive insulin causes weight gain and obesity.
Hormones are essentially chemical messengers. They are produced by the endocrine system, a network of glands found throughout the body to maintain proper function. The pea-sized pituitary gland in the brain is often called the master gland because it produces many different hormones that control metabolic processes in other parts of the body. For example, it secretes growth hormone, which signals the rest of the body, including the bones and muscles, to grow bigger. The butterfly-shaped thyroid gland in the neck produces thyroid hormone to deliver its message to the rest of the body. When it receives this signal, the heart may beat faster, breathing may accelerate, and the basal metabolic rate may increase. Similarly, the pancreas produces insulin, a hormone that delivers several different messages mostly relating to the intake and storage of food energy.
INSULIN BASICS
WHEN WE EAT, foods are broken down in the stomach and small intestine for easier absorption. All foods are composed of three main constituents, called macronutrients. These are proteins, fats, and carbohydrates, and they are all handled differently by the digestive system. Proteins are broken down into amino acids. Fats are broken down into fatty acids. Carbohydrates, composed of chains of sugars, are broken down into smaller sugars, including glucose. Micronutrients, as the name implies, are nutrients that are necessary for good health in far smaller quantities, such as vitamins and minerals.
One of insulin’s roles is to facilitate the uptake of glucose into cells for energy, by opening a channel to allow it inside. Hormones find their target cell by binding to receptors on the cell surface, much like a key fitting into a lock. Only the correct hormone can open the receptor and deliver the message. Insulin works like the key, fitting snugly into the lock on the cell to open a gateway for glucose. Every cell in the body can use glucose for energy. Without insulin, glucose circulating in the blood cannot easily enter the cell.
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