More on this book
Community
Kindle Notes & Highlights
by
Jason Fung
glycerol is used for gluconeogenesis, so the amino acids formerly used can be reserved for protein synthesis. The fatty acids are used directly for energy by most tissues of the body, though not the brain. The body uses fatty acids to produce ketone bodies, which are capable of crossing the blood-brain barrier and are used by the brain 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. 5. The
...more
This highlight has been truncated due to consecutive passage length restrictions.
levels prevent any decrease in metabolic rate. There is a normal amount o...
This highlight has been truncated due to consecutive passage length restrictions.
it is not being used for energy. In essence, what we are describing here is the process of switching from burning glucose to burning fat. Fat is simply the body’s stored food energy. In times of low food availability, stored food is naturally released to fill the void. The body does not “b...
This highlight has been truncated due to consecutive passage length restrictions.
Periods of low food availability have always been a natural part of human history, and our body evolved mechanisms to adapt
The body is not “shutting down”; it’s merely changing fuel sources, from food to our own fat.
A decreased insulin level is one of the most consistent hormonal effects of fasting.
the most effective method of reducing insulin is to avoid all foods altogether.
Extended fasting over 4 days leads to decreased insulin and blood sugar levels.
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.
In a study of supervised fasts with only water and vitamins lasting up to 117 days,
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.
studies show that after a four-day fast, resting energy expenditure increased by 12 percent. Rather than slowing the metabolism, fasting revs it up.
Excessively low growth hormone levels in adults leads to more body fat, less muscle mass, and decreased bone density
overeating suppresses growth
hormone levels by as much as 80 percent.
The most potent natural stimulus to growth hormone sec...
This highlight has been truncated due to consecutive passage length restrictions.
In one study, over a five-day fasting period, growth hormone secreti...
This highlight has been truncated due to consecutive passage length restrictions.
Interestingly, very low-calorie diets are not able to provoke the same growth hormone response.
Fasting significantly increases growth hormone.
If it has a nutrition label, it should be avoided. Real foods, whether broccoli or beef, have no labels.
The true secret to healthy eating is this: Just eat real food.
The basics of good nutrition can be summarized in these simple rules. Eat whole, unprocessed foods.
Avoid sugar. Avoid refined grains. Eat a diet high in natural fats. Balance feeding with fasting.
we encourage consuming plenty of noncaloric liquids (water, tea, coffee) and homemade bone broth, which is full of nutrients.
Fasting does not make you tired. Fasting does not burn muscle. There is no starvation mode from fasting where you shrivel up into the fetal position on your couch.
fasting has the potential to unleash the anti-aging properties of growth hormone without any of the problems of taking artificial growth hormone.
fasting helps with weight loss (Chapter 5) and type 2 diabetes (Chapter 6), boosts brainpower and slows aging (Chap...
This highlight has been truncated due to consecutive passage length restrictions.
knew one thing for sure: everyone I knew who’d got on diabetes medication had lived miserably and eventually died from the disease.
“Fasting is the greatest remedy—the physician within.
“The best of all medicines is resting and fasting.
metabolism revs up, not down, during fasting.
we’re designed to function well during periods of fasting—our bodies don’t start to shut down or go into “starvation mode.
Myth #2: Fasting Makes You Burn Muscle
One persistent myth of fasting is that it burns muscle, that our body, if we’re not eating, will immediately start using our muscles as an energ...
This highlight has been truncated due to consecutive passage length restrictions.
Alternate-day fasting over seventy days decreased body weight by 6 percent, but fat mass decreased by 11.4 percent and lean mass (muscle and bone) did not change at all.
During fasting, the body switches from burning sugar (carbohydrates) to fat for energy. Protein is spared.
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.
You can’t outrun a bad diet.
Body fat is, at its core, stored energy for us to “eat” when there is no food. It’s not there for looks, right? So, when we fast, we “eat” our own fat.
During fasting, hormonal changes kick in to give us more energy (increased adrenaline) and preserve our lean muscles and bones (increased growth hormone).
alternate-day fasting.
Myth #3: Fasting Causes Low Blood Sugar
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. They usually attribute this to achieving some kind of spiritual enlightenment, but the truth is much more down-to-earth and scientific than that: it’s the ketones! Ketones are a “superfood” for the brain. 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
...more
function optimally on fewer calories than I thought necessary.
For longer fasts, it is a good idea to take a general multivitamin.
The longest fast recorded lasted 382 days, and a simple multivitamin prevented any vitamin deficiencies.
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 the aging process Decreases inflammation
refined carbohydrates are a prime contributor to high insulin levels,
