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Kindle Notes & Highlights
by
Jason Fung
The key hormone involved in both the storage and use of food energy is insulin, which rises during meals. Both carbohydrates and protein stimulate insulin.
some proteins can stimulate insulin as much as some carbohydrate-containing foods. Fats are directly absorbed as fat and have minimal effect on insulin.
Second, insulin helps store the excess energy. There are two
ways to store the energy. Glucose molecules can be linked into long chains called glycogen and then stored in the liver. There is, however, a limit to the amount of glycogen that can be stored away. Once this limit is reached, the body starts to turn glucose into fat. This ...
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This newly created fat can be stored in the liver or in fat d...
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The process of using and storing food energy that occurs when we eat goes in reverse when we fast. Insulin levels drop, signaling the body to start burning stored energy. Glycogen (the glucose that’s stored in the liver) is the most easily accessible energy source, and the liver stores enough to provide energy for twenty-four hours or so. After that, the body starts to break down stored body fat for energy.
Gluconeogenesis (twenty-four hours to two days after beginning fasting): At this point, glycogen stores have run out. The liver manufactures new glucose from amino acids in a process called gluconeogenesis (literally, “making new glucose”).
Ketosis (two to three days after beginning fasting): Low insulin levels stimulate lipolysis, the breakdown of fat for energy.
After four days of fasting, approximately 75 percent of the energy used by the brain is provided by ketones. The two major types of ketones produced are beta-hydroxybutyrate and acetoacetate, which can increase over seventyfold during fasting.
The body does not “burn muscle” in an effort to feed itself until all the fat stores are used up.
All foods raise insulin to some degree. Refined carbohydrates tend to raise insulin the most and fatty foods the least, but insulin still goes up in both cases.
Regularly lowering insulin levels leads to improved insulin sensitivity—your body becomes more responsive to insulin.
Lowering insulin also rids the body of excess salt and water because insulin is well known to cause salt and water retention in the kidneys.
Other vitamins and minerals: The daily use of a general multivitamin supplement will provide the recommended daily amount of micronutrients. A therapeutic fast of 382 days was maintained with only a multivitamin with no harmful effects on health. In fact, this man felt terrific during this entire period.
In a study of supervised fasts with only water and vitamins lasting up to 117 days, researchers confirmed that there were no changes in serum electrolytes, lipids, proteins, or amino acids. Moreover, they found that hunger was virtually absent during these prolonged fasts.
Most people expect that a period of fasting will leave them feeling tired and drained of energy. However, the vast majority of people
experience the exact opposite: they feel energized and revitalized during fasting.
Partly this is because the body is still being fueled—it’s just getting energy from burning f...
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Excessively low growth hormone levels in adults leads to more body fat, less muscle mass, and decreased bone density (osteopenia).
A randomized controlled study found that in men, six months of growth hormone replacement increased lean mass (bone and muscle) by an astounding 3.7 kilograms (8.2 pounds), even as fat mass decreased by 2.4 kilograms (5.3 pounds). Similar results were found in women.
Meals very effectively suppress the secretion of growth hormone, so if we’re eating three meals per day, we get effectively no growth hormone during the day. Worse, overeating suppresses growth hormone levels by as much as 80 percent.
The most potent natural stimulus to growth hormone secretion is fasting. In one study, over a five-day fasting period, growth hormone secretion more than doubled.
very low-calorie diets are not able to provoke the same growth hormone response.
a 1992 study showed a fivefold increase in growth hormone in response to a two-day fast.
higher growth hormone level may improve recovery time from hard workouts. The increased adrenaline also allows a more intense workout. Athletes can train harder and recover faster.
Modern medicine’s greatest challenges are metabolic diseases: obesity, type 2 diabetes, high blood pressure, high blood cholesterol, and fatty liver, collectively known as metabolic syndrome. The presence of any of these diseases tremendously increases the risk of heart disease, stroke, cancer, and premature death. And the roots of metabolic syndrome lie in the Western diet, with its abundance of sugar, high fructose corn syrup, artificial flavors, artificial sweeteners, and overdependence on refined grains.
An absolute fast withholds both food and liquid. This may be done for religious purposes, such as during the holy month of Ramadan in the Muslim tradition. During that time, no food or drink is consumed during the period between sunrise and sunset. Medically, this combines the food restriction of fasting with dehydration due to the restriction of fluids. This makes an absolute fast much more physically difficult and limits the duration to fairly short periods. Absolute fasts are not generally recommended for health purposes.
From an evolutionary standpoint, eating three meals a day and snacking throughout the day is not a requirement for survival or good health.
Famous nutrition researcher Ancel Keys often considered Crete the poster child for the healthy Mediterranean diet. However, there was a critically important factor of their diet that he completely dismissed: most of the population of Crete followed the Greek Orthodox tradition of fasting. This may have contributed to the healthy longevity of this population.
Buddhist monks are known to abstain from eating after noon, fasting until the next morning.
One early fasting advocate was Hippocrates of Cos (c. 460–c. 370 BC), widely considered the father of modern medicine.
He advised that treatment for obesity should include exertion after meals and eating a high-fat diet, and he recommended that “they should, moreover, eat only once a day.”
Renowned ancient Greek thinkers Plato and his student Aristotle were also staunch supporters of fasting.
The ancient Greeks believed that medical treatments could be observed from nature, and since humans, like most animals, naturally avoid eating when they become sick, they believed fasting to be a natural remedy for illness. In fact, fasting can be considered an instinct, since all animals—dogs, cats, cattle, sheep, and also humans—avoid food when sick. Think about the last time you had the flu, or even a cold. The last thing you probably wanted to do was eat. So fasting can be considered a universal human instinct for handling multiple kinds of illnesses.
After a large meal, blood is shunted to your digestive system to cope with the huge influx of food, leaving less blood to go to the brain.
metabolism revs up, not down, during fasting.
fasting every other day for twenty-two days resulted in no measurable decrease in BMR.
In another study, four days of continuous fasting increased BMR by 12 percent.
We store food energy as body fat and use this as fuel when food is not available. Muscle, on the other hand, is preserved until body fat becomes so low that the body has no choice but to turn to muscle. This will only happen when body fat is at less than 4 percent.
for the first twenty-four to forty-eight hours after you stop eating, until it runs out of glycogen. With no more sugar to burn, the body switches to burning fat.
At the same time, protein oxidation—that is, burning protein, such as muscle, for fuel—actually decreases. The normal protein breakdown of around seventy-five grams per day falls to fifteen to twenty grams per day during fasting. Rather than burning muscle during fasting, we start conserving muscle.
fasting is one of the most potent stimuli for growth hormone secretion, and increased growth hormone helps maintain lean body mass.
Exercise is the only reliable way to build muscle.
During fasting, hormonal changes kick in to give us more energy (increased adrenaline)
People who engage in fasting for religious or spiritual purposes often report feelings of extreme clear-headedness and physical and emotional well-being. Some even feel a sense of euphoria.
When the body and brain are fueled primarily by fatty acids and ketones, respectively, the “brain fog,” mood swings, and emotional instability that are caused by wild fluctuations in blood sugar become a thing of the past and clear thinking is the new normal.
If you fast for longer than twenty-four to thirty-six hours, glycogen stores become depleted.
Fasting: Improves mental clarity and concentration Induces weight and body fat loss Lowers blood sugar levels Improves insulin sensitivity Increases energy Improves fat-burning Lowers blood cholesterol Prevents Alzheimer’s disease Extends life Reverses aging process Decreases inflammation
Type 2 diabetes is a dietary disease, and it requires a dietary solution. Most importantly, it is a curable disease.
It is so simple that it can be explained in two sentences: Eat nothing. Drink water, tea, coffee, or bone broth.
