The Obesity Code: Unlocking the Secrets of Weight Loss (original 2016; edition 2016)
In this highly readable and provocative book, Dr. Jason Fung sets out an original, robust theory of obesity that provides startling insights into proper nutrition. Flying in the face of the weight-loss recommendations that have failed in the past, this book reveals that obesity is a hormonal, not a caloric imbalance. As he explores the latest in nutritional science, Dr. Fung provides practical, effective advice on weight loss and the treatment of Type 2 diabetes based on sound scientific principles.… (more)
|Title:||The Obesity Code: Unlocking the Secrets of Weight Loss|
|Authors:||Dr. Jason Fung (Author)|
|Info:||Greystone Books (2016), Edition: 1, 296 pages|
The Obesity Code: Unlocking the Secrets of Weight Loss by Dr. Jason Fung (2016)
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This book is dedicated to my beautiful wife, Mina. Thank you for your love and the strength you give me. I could not do it without you, nor would I ever want to.
THE ART OF medicine is quite peculiar. Once in a while, medical treatments become established that don't really work.
The biological parents had very little or nothing to do with raising these children, or teaching them nutritional values or attitudes toward exercise. Yet the tendency toward obesity followed them like ducklings.
Approximately 70 percent of the variance in obesity is familial.
Seventy percent of your tendency to gain weight is determined by your parentage. Obesity is overwhelmingly inherited.
However, it is immediately clear that inheritance cannot be the sole factor leading to the obesity epidemic. The incidence of obesity has been relatively stable through the decades. Most of the obesity epidemic materialized within a single generation. Our genes have not changed in that time span.
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 decision to eat or not is principally hormonal.
Body-fat regulation is under automatic control, like breathing.
Since hormones control both Calories In and Calories Out, obesity is a hormonal, not a caloric, disorder.
In response to caloric reduction, metabolism decreases almost immediately, and that decrease persists more or less indefinitely.
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.
There are two major adaptations to caloric reduction. The first change, as we have seen, is a dramatic reduction in total energy expenditure. The second key change is that the hormonal signals that stimulate hunger increase.
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.
Functional magnetic resonance imaging studies show that areas of the brain controlling emotion and cognition light up in response to food stimuli. Areas of the prefrontal cortex involved with restraint show decreased activity. In other words, it is harder for people who have lost weight to resist food.
"Eat Less" does not work. That's a fact. Accept it.
The overwhelming majority of total energy expenditure is not exercise but the basal metabolic rate: metabolic housekeeping tasks such as breathing, maintaining body temperature, keeping the heart pumping, maintaining the vital organs, brain function, liver function, kidney function, etc.
The vast majority (95 percent) of calories are used for basal metabolism.
Exercise is like brushing your teeth. It is good for you and should be done every day. Just don't expect to lose weight.
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.
In addition, the benefit of exercise has a natural upper limit. You cannot make up for dietary indiscretions by increasing exercise. You can't outrun a poor diet. Furthermore, more exercise is not always better. Exercise represents a stress on the body. Small amounts are beneficial, but excessive amounts are detrimental.
Neurons in these hypothalamic areas were somehow responsible for setting an ideal weight, the body set weight.
The vast majority of obese people are not deficient in leptin. Their leptin levels are high, not low. But these high levels did not produce the desired effect of lowering body fatness. Obesity is a state of leptin resistance.
Giving leptin doesn't make people thin. Human obesity is a disease of leptin resistance, not leptin deficiency.
Obesity is a hormonal dysregulation of fat mass.
Insulin causes obesity–which means that insulin must be one of the major controllers of the body set weight.
Hormones are central to understanding obesity. Everything about human metabolism, including the body set weight, is hormonally regulated. A critical physiological variable such as body fatness is not left up to the vagaries of daily caloric intake and exercise. Instead, hormones precisely and tightly regulate body fat. We don't consciously control our body weight any more than we control our heart rates, our basal metabolic rates, our body temperatures or our breathing. These are all automatically regulated, and so is our weight. Hormones tell us we are hungry (ghrelin). Hormones tell us we are full (peptide YY, cholecystokinin). Hormones increase energy expenditure (adrenalin). Hormones shut down energy expenditure (thyroid hormone). Obesity is a hormonal dysregulation of fat accumulation. Calories are nothing more than the proximate cause of obesity.
Obesity is a hormonal, not a caloric imbalance.
However, the undeniable fact remains that excess cortisol causes weight gain.
And so, by extension, stress causes weight gain–something that many people have intuitively understood, despite the lack of rigorous evidence. Stress contains neither calories nor carbohydrates, but can still lead to obesity. Long-term stress leads to long-term elevated cortisol levels, which leads to extra pounds.
Population studies consistently link short sleep duration and excess weight, generally with seven hours being the point where weight gain starts. Sleeping five to six hours was associated with a more than 50 percent increased risk of weight gain. The more sleep deprivation, the more weight gained.
SLEEP DEPRIVATION IS a potent psychological stressor and thus stimulates cortisol. This, in turn, results in both high insulin levels and insulin resistance. A single night of sleep deprivation increases cortisol levels by more than 100 percent. By the next evening, cortisol is still 37 percent to 45 percent higher.
Refined carbohydrates are easy to become addicted to and overeat precisely because there are no natural satiety hormones for refined carbohydrates. The reason, of course, is that refined carbohydrates are not natural foods but are instead highly processed. Their toxicity lies in that processing.
Total carbohydrate intake was not the entire story. Sugar seemed to be contributing much more to obesity than other refined carbohydrates.
As the patient's insulin levels increased, his or her levels of insulin resistance increase in lock step–a protective mechanism and a very good one. If insulin resistance did not develop, the high insulin levels would rapidly lead to very, very low blood sugars. The resulting severe hypoglycemia would quickly lead to seizures and death. Since the body doesn't want to die (and neither do we), it protects itself by developing insulin resistance–demonstrating homeostasis.
With normal but persistent amounts of insulin alone, these healthy, young, lean men can be made insulin resistant.
SO WE KNOW that insulin causes insulin resistance. But insulin resistance also causes high insulin–a classic vicious or self-reinforcing, cycle. The higher the insulin levels, the greater the insulin resistance. The greater the resistance, the higher the levels.
Obesity drives itself. A long-standing obesity cycle is extremely difficult to break, and dietary changes along may not be sufficient.
The longer you are obese, the more insulin resistance you have. Gradually, that insulin resistance will cause even your fasting insulin levels to rise.
Lack of exercise may lead to insulin resistance in the muscles.
High levels alone do not lead to resistance. There are two requirements for resistance–high hormonal levels and constant stimulus.
The first myth is that eating frequently will increase your metabolic rate. Your metabolic rate does increase slightly after meals to digest your food–the thermogenic effect of food. However, the overall difference is extremely small. Eating six small meals per day causes the metabolic rate to go up six times a day, but only a little. Eating three larger meals per day causes metabolic rate to go up three times a day, but a lot each time. In the end, it's a wash.
The second myth is that eating frequently controls hunger, but evidence is impossible to find.
The third myth is that eating frequently keeps blood glucose from becoming too low. But unless you have diabetes, your blood sugars are stable whether you eat six times a day or six times a month.
Crazier still–we have been brainwashed to believe that constant eating is somehow good for us! Not just acceptable, but healthy.
High levels of fructose will cause fatty liver. Fatty liver is absolutely crucial to the development of insulin resistance in the liver.
Despite having a minimal effect on blood sugars, both aspartame and stevia raised insulin levels higher even than table sugar.
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.
Blood glucose does not drive weight gain. But hormones–particularly insulin and cortisol–do.
Insulin causes obesity. The goal should therefore be to lower insulin levels–not glucose levels. The unspoken assumption is that glucose is the only stimulant to insulin secretion. This turns out not to be true at all.
But all foods cause insulin secretion.
Insulin can increase independently of blood sugar.
Fatty foods can also stimulate insulin, but pure fats, such as olive oil do not stimulate insulin or glucose.
So the incretin hormones produce two opposing effects. Increased insulin promotes weight gain, but increased satiety suppresses it–which is consistent with personal experience. Animal proteins tend to cause you to feel fuller for longer, with whey having the greatest effect.
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.
Heart attacks and strokes are predominantly inflammatory diseases, rather than simply diseases of high cholesterol levels.
The liver manufactures the overwhelming majority–80 percent–of the blood cholesterol, with only 20 percent coming from diet. Cholesterol is often portrayed as some harmful poisonous substance that must be eliminated, but nothing could be farther from the truth. Cholesterol is a key building block in the membranes that surround all the cells in our body. In fact, it's so vital that every cell in the body except the brain has the ability to make it. If you reduce cholesterol in your diet, your body will simply make more.
Asking how much sugar is acceptable is like asking how many cigarettes are acceptable.
A recent Spanish study found that adding 100 pistachios to one's daily diet improved fasting glucose, insulin and insulin resistance.
Are snacks necessary? No. Simply ask yourself this question. Are you really hungry or just bored? Keep snacks completely out of sight. If you have a snack habit, replace that habit loop with one that is less destructive to your health. Perhaps a cup of green tea in the afternoon should be your new habit. There's a simple answer to the question of what to eat at snack time. Nothing. Don't eat snacks. Period. Simply your life.
In thinking about what to eat for breakfast, consider this: If you are not hungry, don't eat anything at all.
However, moderate consumption of red wine does not raise insulin or impair insulin sensitivity, and therefore may be enjoyed. Up to two glasses a day is not associated with major weight gain and may improve insulin sensitivity. The alcohol itself, even from beer, seems to have minimal effects on insulin secretion or insulin resistance. It is sometimes said that you get fat from the foods you eat with the alcohol rather than from the alcohol itself. There may be some truth to that, although the evidence is sparse.
Coffee, even the decaffeinated version, appears to protect against type 2 diabetes.
Coffee may guard against the neurologic diseases Alzheimer's, Parkinson's disease, liver cirrhosis and liver cancer.
Blood glucose levels remain normal as the body switches over to burning fat for energy. This effect occurs with fasting periods as short as twenty-four to thirty-six hours.
Insulin causes salt and water retention in the kidney, so lowering insulin levels rids the body of excess salt and water.
Growth hormone is know to increase the availability and utility of fats for fuel. It also helps to preserve muscle mass and bone density. Growth hormone secretion is difficult to measure accurately because of its intermittent release, but it decreases steadily with age. One of the most potent stimuli to growth hormone secretion is fasting.
The human body has evolved to survive episodic periods of starvation. Fat is stored energy and muscle is functional tissue. Fat is burned first.
Personal experience with hundreds of both men and women fail to convince me of any substantial difference between the sexes when it comes to fasting.
In other words, feasting must be followed by fasting. When we remove the fasting and keep all the feasting, we get weight gain.
Scientific studies conclude that fasting carries significant health benefits. Metabolism increases, energy increases and blood sugars decrease.
During a twenty-four hour fast, you fast from dinner (or lunch or breakfast) the first day until dinner (or lunch or breakfast) the next day. Practically, this means missing breakfast, lunch and snacks on the fasting day and only eating a single meal (dinner). Essentially, you skip two meals as you fast from 7:00 p.m. to 7:00 p.m. the next day.
Aim to drink two liters of water daily.
Green tea is an especially good choice here. The catechins in green tea are believed to help suppress appetite.
Homemade bone broth, made from beef, pork, chicken or fish bones, is a good choice for fasting days. Vegetable broth is a suitable alternative, although bone broth contains more nutrients. Adding a good pinch of sea salt to the broth will help you stay hydrated.
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