Life in the Fasting Lane: The Essential Guide to Making Intermittent Fasting Simple, Sustainable, and Enjoyable

by Jason Fung

A study of four consecutive days of fasting—that is, four full days without any food to eat—showed that BMR increases by about 10 percent. Yes, metabolic rate increases when you don’t eat. Why? We know that fasting decreases insulin but increases counter-regulatory hormones, so called because they run counter to insulin. If insulin falls, these hormones go up. If insulin rises, these hormones go down. The counter-regulatory hormones include noradrenaline (responsible for stimulating muscle contraction and heart rate), growth hormone (stimulates cell growth and regeneration), and cortisol (the so-called stress hormone, responsible for triggering motivation and action). If noradrenaline increases, then metabolic rate is expected to also go up.

that rats who were subjected to fasts showed fewer symptoms in models of Alzheimer’s, Huntington’s, and Parkinson’s disease.

In Denmark there is about a 4 percent rate of organ donation. In neighboring Sweden, that rate is 89 percent. The Danes and Swedes are very much similar in almost all respects, so why the huge discrepancy? The answer lies in the default state. In Denmark, you check the box if you would like to opt into the organ donor program. In Sweden, you check the box if you would like to opt out of the organ donor program. The difference does not lie in the people or their values.

a liberal low-carb diet is generally considered to consist of 50 to 100 grams of carbohydrates a day. A moderate low-carb diet is between 21 and 50 grams a day, while a strict, ketogenic diet is 20 grams or less a day. In the Western world, men typically eat about 200 to 330 grams of carbs a day, while women eat around 180 to 230 grams daily.

How long do I have to fast to get into fat-burning mode? It begins after having fasted for sixteen hours straight. If you fast just by skipping lunch, you’re certainly working your fasting muscle, but you’re not yet in the fat-burning zone. What is autophagy and when does it start? The word autophagy derives from the Greek “auto” (self) and “phagein” (to eat). The word literally means “to eat oneself.” This is the body’s way of getting rid of all the broken-down, old cell parts that don’t serve the body. It’s different for everyone, but it starts after twenty-four to thirty-six hours of not eating, increases 300 percent at thirty-six hours,