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Kindle Notes & Highlights
by
Jason Fung
In addition, insulin levels have an inverse correlation to memory—that is, the lower the insulin level, the more memory improves.
So fasting provides neurological benefits two ways: it decreases insulin and leads to consistent, maintained weight loss.
In a process called apoptosis, also known as programmed cell death, cells that reach a certain age are programmed to commit suicide.
Increased levels of glucose, insulin, and proteins all turn off autophagy. And it doesn’t take much. Even as little as 3 grams of the amino acid leucine can stop autophagy.
When we eat carbohydrates or protein, insulin is secreted, and the increased insulin levels, or even just the amino acids from the breakdown of ingested protein, activate the mTOR pathway. The body senses that food is available and decides that since there’s plenty of energy to go around, there’s no need to eliminate the old subcellular machinery. The end result is the suppression of autophagy.
Another risk factor for heart disease is a type of fat called triglycerides. When glycogen stores in the liver are full, the liver starts converting excess carbohydrates into triglycerides instead. These triglycerides are then exported out of the liver as very low density lipoprotein (VLDL). VLDL is used to form LDL.
High levels of triglycerides in the blood are strongly associated with cardiovascular disease. It is almost as powerful a risk factor as high LDL cholesterol, which is what doctors and patients tend to be more concerned about.
Fortunately, high triglycerides can be treated with a low-carbohydrate diet, which lowers the rate at which the liver creates triglycerides. But while triglyceride levels respond to diet, the same cannot be said for cholesterol.
Unfortunately, this idea is entirely wrong. The scientific community has long known that eating less cholesterol does not lower blood cholesterol. Our liver generates 80 percent of the cholesterol found in the blood, so eating less cholesterol makes little or no difference.
This makes as much sense as supposing that eating beef heart will make your own heart stronger, but then, this was 1913. That year, Russian scientist Nikolai Anichkov discovered that feeding cholesterol to rabbits caused atherosclerosis. Rabbits, however, are herbivores and aren’t meant to eat foods that contain cholesterol. Feeding a lion hay would also cause health problems. Unfortunately, this fundamental fact was not appreciated in the rush to find a culprit for the plaques.
So why does fasting affect the liver’s production of cholesterol? As dietary carbohydrates decline, the liver decreases its synthesis of triglycerides—since excess carbohydrates are converted to triglycerides, the absence of carbohydrates means fewer triglycerides. Remember that triglycerides are released from the liver as VLDL, which is the precursor of LDL. Therefore, reduced VLDL eventually results in lowered LDL.
Overall, fasting produces significant improvements in multiple cardiac risk factors. For people worried about heart attacks and strokes, the question is not “Why are you fasting?” but “Why are you not fasting?”
Studies of circadian rhythm confirm that for most people, hunger is very low first thing in the morning, even though it has been twelve to fourteen hours since the last meal. Conversely, hunger at dinnertime is often very high, even though we have often eaten lunch just a mere six hours ago.
The reason great restaurants spend so much time and energy on plating food is because they understand that our enjoyment does not begin with the first bite—it begins when we see the food. An attractively plated meal makes us hungrier than the same food slopped haphazardly into a dog dish.
we consistently eat every morning at 7:00 a.m., then we develop a conditioned response to that time and become hungry at 7:00 a.m., even if we ate a huge meal at dinner the night before. The same applies to lunch and dinnertime. We become hungry merely because of the time, not any true intrinsic hunger. This
Children, on the other hand, often refuse food early in the morning because they are simply not hungry.
Intermittent fasting offers a unique solution. By randomly skipping meals and varying the intervals at which we eat, we can break our habit of eating three times a day, come hell or high water. We no longer have a conditioned response of hunger every three to five hours.
Here’s the simplest way to break associations between food and anything else: Eat only at the table. No eating at your computer station. No eating in the car. No eating on the couch. No eating in bed. No eating in the lecture hall. No eating at the ball game. Try to avoid mindless eating—every meal should be enjoyed as a meal, not as something eaten while watching a movie.
It’s also helpful to avoid artificial sweeteners. Even though they contain no calories, they may still kick off the cephalic phase response, stimulating hunger as well as insulin production.
Recent studies confirm that diet sodas are generally not helpful for weight loss, probably because they trigger hunger but don’t satisfy it.
Second, try to physically remove yourself from all food stimuli during a fast. Cooking a meal or even just seeing and smelling food while fasting is almost unbearably difficult.
One of our most important tips for fasting is to stay busy. Working through lunch and staying busy means I often don’t even remember to be hungry.
Think back to a time when you skipped lunch. Perhaps you were caught up in a meeting and couldn’t get away. At first, you got hungry. The hunger built and built, but there was nothing to be done. But what happened after an hour or so? The hunger entirely dissipated. The wave had passed.
How can people fast for days without being hungry? It comes down to the fact that hunger is not determined by not eating for a certain period of time. Rather, it is a hormonal signal. It does not come about simply because the stomach is empty.
In children, proper growth outweighs all other health concerns, and adequate nutrition is an absolute prerequisite for normal growth. Restricting calories also restricts the essential nutrients necessary for proper growth and the development of vital organs, especially the brain.
The most common medications that cause problems during fasting are aspirin, metformin, and iron and magnesium supplements.
Magnesium supplements taken orally are often poorly absorbed through the intestines, leading to diarrhea. Taking magnesium with food often reduces these symptoms. Low magnesium levels are particularly common in type 2 diabetes.
During a fast, small amounts of pure fat or almost pure fat (a spoonful of olive or coconut oil, a pat of butter), and for some, even a very small amount of solid food, such as macadamia nuts or walnuts—something that is primarily fat with a negligible amount of carbohydrate and little to no protein—can be consumed without interfering with the physiological benefits of the fast.
The IDM fast permits water, tea, and coffee. Sugar, honey, agave nectar, and other sweeteners are not permitted. Artificial sweeteners or flavors are not allowed, but natural flavors such as lemon juice, mint, cinnamon, or other spices are.
All types of tea are excellent choices, including green, black, oolong, and herbal. Green tea is an especially good choice during a fast: the catechins in green tea are believed to help suppress appetite.
Herbal teas are not true teas because they do not contain tea leaves. However, they also are great for fasting. Cinnamon tea and ginger tea have both been used for their reputed appetite-suppressing power. Mint tea and chamomile tea are often used for their soothing properties.
We also permit a small amount of cream or coconut oil to be added to coffee or tea. While this does technically mean it’s not a true fast, the effect is small enough that it seems to make no difference to the overall outcome of the fast.
There are many different fasting regimens, and there’s no “best” one. They all work to different degrees for different people. One regimen may work for one person but be utterly ineffective for the next. One person may prefer shorter fasts while another prefers longer ones.
In the IDM Program, shorter regimens are generally used by those mostly interested in weight loss rather than in treating type 2 diabetes, fatty liver disease, or other metabolic diseases. However, shorter, more frequent fasts still often work well for these conditions.
But while a daily twelve-hour fast may be a great preventative strategy, it may not be powerful enough to reverse weight gain. Slightly longer fasting periods are often required for that.
A Swedish bodybuilder named Martin Berkhan popularized this regimen, which is sometimes called the LeanGains method. Several years afterwards, a book called The 8-Hour Diet espoused the same eight-hour eating window.
The daily sixteen-hour fast certainly has more power than the daily twelve-hour fast, but it should be combined with a low-carbohydrate diet for the best effect. Weight loss on this regimen tends to be slow and steady.
An earlier 1992 study showed similar results. In response to the same meal given either early or late in the day, the insulin response was 25 to 50 percent greater in the evening.
Eating the largest meal in the evening seems to cause a much larger rise in insulin than eating earlier. Folk wisdom, of course, also advises to avoid eating large meals in the evening.
At 8 a.m., our hunger is actively suppressed. It is counterproductive to force-feed ourselves then. What’s the point? Eating does not produce weight loss. Forcing ourselves to eat at a time when we are not hungry is not a winning strategy.
Hunger is maximally stimulated at approximately 7:50 p.m. At this time, insulin is maximally stimulated by food, which means that the same amount of food results in higher insulin levels. This higher insulin level will naturally drive weight gain.
So the optimal strategy seems to be eating the largest meal in the midday, sometime between noon and 3:00 p.m., and only a small amount in the evening hours. Interestingly, this is the traditional Mediterranean eating pattern. They eat a large lunch, followed by a siesta in the afternoon, and then have a small, almost snack-sized dinner. While we often think of the Mediterranean diet as healthy due to the type of foods in it, the timing of meals in the Mediterranean may also play a role. References
The 5:2 diet consists of five normal eating days. On the other two “fast” days, women may eat up to 500 calories per day and men up to 600 calories.
our IDM Program, we use thirty-six-hour fasts, on a three-times-a-week schedule, with patients who have type 2 diabetes.
Do not change your life to fit your fasting schedule—change your fasting schedule to fit your life.
Try breaking your fast with a snack or small dish to start, then wait for thirty to sixty minutes before eating your main meal.
Fit fasting into your schedule, not the other way around. If you know you are going to eat a large dinner, then skip breakfast and lunch. One of the easiest ways to fit fasting into your life is to skip breakfast, since that’s not a meal we socialize over as much as lunch or dinner. During workdays, skipping breakfast is easy to do without anybody noticing. This will quite easily allow you to fast for sixteen hours.
