The Obesity Code

The Obesity Code

Jason Fung

A calorie is a unit of food energy used by the body for various functions such as breathing,building new muscle and bone,pumping blood and other metabolic tasks. Some food energy is stored as fat. Calories In is the food energy that we eat. Calories Out is the energy expended for all of these various metabolic functions.

excess Calories may certainly be the proximate cause of weight gain, but not its ultimate cause. What’s the difference between proximate and ultimate? The proximate cause is immediately responsible, whereas the ultimate cause is what started the chain of events.

Why does a plane crash? The proximate cause is, “there was not enough lift to overcome gravity”—again, absolutely true, but not in any way useful. The ultimate cause might be
• human error,
• mechanical fault and/or
• inclement weather.
Understanding the ultimate cause leads to effective solutions such as better pilot training or tighter maintenance schedules. Advice to “generate more lift than gravity” (larger wings, more powerful engines) will not reduce plane crashes

All foods can be divided into three different macro-nutrient groups: fat, protein and carbohydrates. The “macro” in “macro nutrients” refers to the fact that the bulk of the food we eat is made up of these three groups. Micronutrients, which make up a very small proportion of the food, include vitamins and minerals such as vitamins A, B, C, D, E and K, as well as minerals such as iron and calcium. Starchy foods and sugars are all carbohydrates.

Food first enters the stomach, where it is mixed with stomach acid and slowly released into the small intestine. Nutrients are extracted throughout the journey through the small and large intestines. What remains is excreted as stool. Proteins are broken down into their building blocks, amino acids. These are used to build and repair the body’s tissues, and the excess is stored. Fats are directly absorbed into the body. Carbohydrates are broken down into their building blocks, sugars.Proteins, fats and carbohydrates all provide caloric energy for the body, but differ greatly in their metabolic processing. This results in different hormonal stimuli.

Obesity is a hormonal dysregulation of fat mass. The body maintains a body set weight, much like a thermostat in a house. When the body set weight is set too high, obesity results. If our current weight is below our body set weight, our body, by stimulating hunger and/or decreasing metabolism, will try to gain weight to reach that body set weight. Thus, excessive eating and slowed metabolism are the result rather than the cause of obesity.

before Discussing insulin, we must understand hormones in general. Hormones are molecules that deliver messages to a target cell. For example, thyroid hormone delivers a message to cells in the thyroid gland to increase its activity. Insulin delivers the message to most human cells to take glucose out of the blood to use for energy. To deliver this message, hormones must attach to the target cell by binding to receptors on the cell surface, much like a lock and key. Insulin acts on the insulin receptor to bring glucose into the cell. Insulin is the key and fts snugly into the lock (the receptor). The door opens and glucose enters. All hormones work in roughly the same fashion.

When we eat, foods are broken down in the stomach and small intestine. Proteins are broken into amino acids. Fats are broken into fatty acids. Carbohydrates, which are chains of sugars, are broken into smaller sugars. Dietary fiber is not broken down; it moves through us without being absorbed. All cells in the body can use blood sugar (glucose). Certain foods, particularly refined carbohydrates, raise blood sugar more than other foods. The rise in blood sugar stimulates insulin release

obesity Develops when the hypothalamus orders the body to increase fat mass to reach the desired body set weight. Available calories are diverted to increase fat, leaving the body short of energy (calories). The body’s rational response is to try to get more calories. It increases the hormonal signals of hunger and decreases hormonal signals of satiety. We can resist the urge to eat and restrict our calorie consumption. Doing so will thwart the hypothalamus for a while, but it has other means of persuasion. The body conserves calories needed for fat growth by shutting down other functions, and metabolism slows. Increased Calories In and decreased Calories Out (eating more and moving less) does not cause obesity, but is instead the result of obesity.


The key to understanding obesity is to understand what regulates body set weight, why body set weight is set so high, and how to reset it lower.

The question is not how to balance calories; the question is how to
balance our hormones. The most crucial question in obesity is how to reduce insulin.

Cortisol is the so-called stress hormone, which mediates the flight-or-fght response, a set of physiological responses to perceived threats. Cortisol, part of a class of steroid hormones called glucocorticoids (glucose + cortex + steroid), is produced in the adrenal cortex.

Cortisol may act through high insulin levels and insulin resistance, but there may also be other pathways of obesity yet to be discovered. 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

sleep Deprivation is a major cause of chronic stress today. Sleep duration has been steadily declining.21 In 1910, people slept nine hours on average. However, recently, more than 30 percent of adults between thirty and sixty-four years of age report getting fewer than six hours of sleep per night.22 Shift workers are especially prone to sleep deprivation and often report fewer than fve hours of sleep per night.23 Population studies consistently link short sleep duration and excess weight,24, 25 generally with seven hours being the point where weight gain starts. Sleeping fve to six hours was associated with a more than 50 percent increased risk of weight gain.26 The more sleep deprivation, the more weight gained.

Highly refned carbohydrates are the most notorious foods for raising blood sugars. High blood sugars lead to high insulin levels. High insulin levels lead to weight gain and obesity.

But the time frame matters a lot. We may try to downplay its effects, but the idea that long-standing obesity is much more diffcult to treat has the stench of truth. So we must acknowledge the phenomenon of time dependence. Obesity at age seventeen has consequences that reach decades into the future.1 Any comprehensive theory of obesity must be able to explain why its duration matters so much. High insulin levels cause weight gain. Food choices play a role in

raising insulin levels. But we are missing yet another pathway that increases insulin, one that is both time dependent and independent of diet: insulin resistance.


What happens in the case of insulin resistance? As discussed before a hormone acts on a cell as a key that fts into a lock. When insulin (the key) no longer fts into the receptor (the lock), the cell is called insulin resistant. Because the ft is poor, the door does not open fully. As a result, less glucose enters. The cell senses that there is too little glucose inside. Instead, glucose is piling up outside the door. Starved for glucose, the cell demands more. To compensate, the body produces extra keys (insulin). The ft is still poor, but more doors are opened, allowing a normal amount of glucose to enter.

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. The cycle keeps going around and around, one element reinforcing the other, until insulin is driven up to extremes. The longer the cycle continues, the worse it سbecomes—that’s why obesity is so time dependent

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Obesity is a hormonal disorder of fat regulation. Insulin is the major hormone that drives weight gain, so the rational therapy is to lower insulin levels. There are multiple ways to achieve this, and we should take advantage of each one. In the rest of this chapter, I will outline a step-by-step approach to accomplish this goal.

STEP 1: REDUCE YOUR CONSUMPTION OF ADDED SUGARS

Read the labels almost ubiquitous in refined and processed foods, sugar is not always labeled as such. Other names include sucrose, glucose, fructose, maltose, dextrose, molasses, hydrolyzed starch, honey, invert sugar, cane sugar, glucose-fructose, high fructose corn syrup, brown sugar, corn sweetener, rice/corn/cane/maple/malt/golden/palm syrup and agavenectar. These aliases attempt to conceal the presence of large amounts of added sugars. A popular trick is to use several different pseudonyms on the food’s label. This trick prevents “sugar” from being listed as the first ingredient.

Just don’t snack: the healthy snaCk is one of the greatest weight-loss deceptions



STEP 2: REDUCE YOUR CONSUMPTION OF REFINED GRAINS

If you reduce your consumption of flour and refined grains, you will substantially improve your weight-loss potential.

Whole wheat and whole grains are an improvement over white
flour, containing more vitamins and fiber. The bran fiber helps protect against the insulin spikes. However, whole-grain flour is still highly processed in a modern flourmill.

Remember: the toxicity in much Western food lies in the processing, rather than in the food itself. The carbohydrates in Western diets are heavily skewed toward refined grains, and are thus highly obesogenic. Eggplant, kale, spinach, carrots, broccoli, peas, Brussels sprouts, tomatoes, asparagus, bell peppers, zucchini, cauliflower, avocados, lettuce, beets, cucumbers, watercress, cabbage, among others, are all extremely healthy carbohydrate containing foods




STEP 3: MODERATE YOUR PROTEIN CONSUMPTION

moderate the amount of protein in your diet to fall within 20 percent to 30 percent of your total calories.



STEP 4: INCREASE YOUR CONSUMPTION OF NATURAL FATS
Of the three major macronutrients (carbohydrates, proteins and fats), dietary fat is the least likely to stimulate insulin. Thus, dietary fat is not inherently fattening, but potentially protective.

Natural, unprocessed fats include olive oil, butter, coconut oil, beef tallow and leaf lard.
In addition to healthy fats, nuts are naturally high in fiber and low in carbohydrates. Walnuts in particular are high in the omega 3 fatty acids. Full-fat dairy is delicious and can be enjoyed without concern of fattening effects.


STEP 5: INCREASE YOUR CONSUMPTION OF PROTECTIVE FACTORS

Fiber Can reduce the insulin-stimulating effects of carbohydrates, making it one of the main protective factors against obesity Natural whole foods contain plenty of fiber, which is often removed during processing. Fruits, berries, vegetables, whole grains, flax seeds, chia seeds, beans, popcorn, nuts, oatmeal and pumpkin seeds provide ample fiber Vinegar is also a protective factor. Used in many traditional foods, it may help reduce insulin spikes. Italians often eat bread dipped in oil and vinegar—a prime example of eating a high-carb food with protective factors. Vinegar is added to sushi rice, which reduces its glycemic index by 20 percent to 40 percent.53 Fish and chips are often eaten with malt vinegar. Apple cider vinegar may be taken diluted in some water


THE LAST PIECE OF THE PUZZLE: FASTING: AN ANCIENT REMEDY

THE BODY’S RESPONSE TO FASTING

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:

1. Feeding: During meals, insulin levels are raised. This allows glucose uptake by tissues such as the muscle or brain for direct use as energy. Excess glucose is stored as glycogen in the liver.

2. The post-absorptive phase (six to twenty-four hours after fasting starts): Insulin levels being to fall. The breakdown of glycogen releases glucose for energy. Glycogen stores last for roughly twenty four hours.

3. Gluconeogenesis (twenty-four hours to two days): The liver manufactures new glucose from amino acids and glycerol. In non-diabetic persons, glucose levels fall but stay within the normal range.

4. Ketosis (one to three days after fasting starts): The storage form of fat, triglycerides, is broken into the glycerol backbone and three fatty acid chains. Glycerol is used for gluconeogenesis. Fatty acids may be used for directly for energy by many tissues in the body, but not the brain. Ketone bodies, capable of crossing the blood-brain barrier, are produced from fatty acids for use by the brain. Ketones can supply up to 75 percent of the energy used by the brain. The two major types of ketones produced are beta hydroxybutyrate and acetoacetate, which can increase more than seventy-fold during fasting.

5. Protein conservation phase (after fve days): High levels of growth hormone maintain muscle mass and lean tissues. The energy for maintenance of basal metabolism is almost entirely met by the use of free fatty acids and ketones. Increased norepinephrine (adrenalin) levels prevent the decrease in metabolic rate.

The human body is well adapted for dealing with the absence of food. What we’re describing here is the process the body undergoes to switch from burning glucose (short term) to burning fat (long term). Fat is simply the body’s stored food energy. In times of food scarcity stored food (fat) is naturally released to fill the void. The body does not “burn muscle” in an effort to feed itself until all the fat stores are used. It’s crucial to note that all these beneficial adaptive changes do not occur in the caloric-reduction diet strategy

Fasting is the most efficient and consistent strategy to decrease insulin levels