Chapter 1 The Origins of Fasting and Food Freedom If you read the words "intermittent fasting" and a mental image of someone sipping water looking miserable and hungry emerged in your mind, I get it. Intermittent fasting has developed a reputation as extreme and overly restrictive. It''s often criticized as a way to prop up a damaging diet culture that is obsessed with weight loss and chasing the "perfect body." The notion of not eating can trigger preexisting negative thoughts and habits, and, in some cases, following strict dietary rules or fasting can be self-punishment disguised as a wellness practice. It''s easy to assume that fasting is just another form of restrictive dieting. But here''s the honest truth: Real intermittent fasting isn''t about punishment, calorie restriction, or restriction at all. In fact, these things are the antithesis of the concepts presented in Intuitive Fasting. And yet you''ll find that many people will still use "chronic calorie restriction" and "intermittent fasting" synonymously.

Let me be clear: chronic calorie restriction and fasting are not the same things. Here''s what makes them different: Chronic calorie restriction: Reducing your average daily caloric intake below what is normal for a long period of time. Intermittent fasting: Limiting how often you eat, or not eating at all, during certain times of the day, week, or month. See the difference? The key to intermittent fasting is when you eat--not how much. Intermittent fasting, especially the type of fasting we''ll be practicing in this book, actually has nothing to do with counting calories, chronically restricting food, or eating less overall. So where does this confusion between fasting and chronic calorie restriction come from? Probably from the fact that one of the practical side effects of intermittent fasting is healthy weight loss. Weight loss is something fasting and calorie restriction do have in common--but that doesn''t mean they''re the same thing. In fact, somewhat ironically, studies have shown that, for weight loss, fasting can be even more effective than chronically lowering your calories.

For example, one study published in the reputable journal Nature showed that in 28 obese adults, fasting led to greater weight loss and fat loss than calorie restriction. If this surprises you, you''re not alone. Many of us are still operating under the old logic that weight loss is all about "calories in and calories out," when the reality is that weight loss is much more complicated than this overly simplistic equation. Your body is not a calorie calculator, it is a chemistry lab, and intermittent fasting resets the beautiful biochemistry lab otherwise known as your metabolism. Intermittent fasting causes fundamental shifts in your body''s physiology that help your body burn more fat, feel less hungry, and regain energy--shifts that we''ll learn about in depth throughout the course of this book. For now, though, let''s focus on the fact that intermittent fasting is simply far easier to maintain than calorie restriction (which can leave you constantly cranky, hangry, and dissatisfied). Most diets fail, and they fail for a reason: chronic caloric restriction will slow down your metabolism and put your body into starvation mode, where it tries to hold on to fat. One study compared the effectiveness of intermittent fasting with continuous calorie restriction and found that intermittent fasting is a great alternative for weight loss, particularly for those who find chronic calorie restriction difficult to maintain.

But wait--aren''t we supposed to eat more frequent, small meals a day to keep our metabolism going? Isn''t that the healthiest way to live and maintain our weight? At first glance, this idea seems legit--but the truth is, this theory doesn''t hold up when put to the test. One randomized trial using two groups of diabetic patients compared the effects on one group of eating five to six small meals a day to the effects on a second group of eating two larger meals. The number of calories the two groups consumed was the same, but the results showed that two larger meals led to greater weight loss, less hepatic fat content, increased oral glucose insulin sensitivity, and more. In other words, it was better for the metabolism, weight loss, and blood sugar balance to stick to the two larger meals. Our bodies are better able to digest and use the food we eat for usable energy when we eat fewer, larger meals a day. Other review studies have shown that despite the fact that snacking is meant to keep you from overeating--and snacks can help you feel satisfied temporarily--they don''t cause you to eat less at your normal meals, which means you end up consuming more food and calories overall. The results of another study on patients who had recently undergone bariatric surgery showed that higher meal frequency was related to diminished weight loss. The ideas of "portion control" and "eat small meals throughout the day" have been drilled into our brains.

But data from the United Kingdom, published in the American Journal of Public Health, indicates that this conventional advice only helps 1 in 210 obese men and 1 in 124 obese women lose weight. Those numbers are shockingly and embarrassingly bad: that is a failure rate of 99.5 percent--and the numbers are even more concerning for morbid obesity. Clearly, the strategies we''re currently using aren''t working. Looking at those numbers, we''re forced to rethink what we''ve been taught about how to successfully lose weight. The truth is, eating all the time, even if it''s only a small amount, costs us a lot. Digesting requires a lot of energy, and it can interfere with other important bodily processes. It''s just plain unnatural to snack before bed, wake up and eat, and then constantly be snacking on granola bars and popcorn throughout the day (however relatively healthy these foods may be).

Another common misconception about fasting is that because fasting can cause weight loss, its health benefits must be attributed to weight loss itself. This theory has actually been studied and disproven. For example, a randomized trial consisting of 100 women--half of whom followed an intermittent fasting regimen and half of whom followed a 25 percent calorie reduction diet--showed that the women in the two groups lost about the same amount of weight after six months, but the women on the fasting diet had a greater increase in insulin sensitivity and a larger reduction in waist circumference, which will undoubtedly make weight management easier in the long term. Other studies, as cited in a large review paper published in the New England Journal of Medicine, have specifically shown that specific benefits of intermittent fasting--such as improvement in glucose regulation, blood pressure, and heart rate, and in the efficacy of endurance and abdominal fat loss--are separate from its effect on weight. As the authors of the paper explain, human and animal studies have shown that the benefits of fasting are not simply the result of fasting-induced weight loss. Instead, they say intermittent fasting awakens powerful healing mechanisms that were lying dormant inside the body. Fasting enhances health and leads to weight loss in ways that are unrelated to a calorie deficit. Instead, fasting triggers shifts in metabolic and hormonal pathways that bring balance back to the body and allow it to maintain a healthy weight more easily, naturally.

In short, you can get healthy so that you can lose weight, instead of trying to lose weight to get healthy. See? I told you I was going to ask you to take everything you knew about fasting and eating and throw it out the window. The Physician Within: The History of Fasting Fasting has been pulled into the weight loss world as the newest big wellness trend, which has led to public misconceptions about fasting being just another fad. But the truth is, fasting isn''t new at all. Name any major religion or spiritual philosophy, and, chances are, it incorporates fasting in some way. In a religious context, going periods of time without food is often a way to gain clarity, show sacrifice, and help one become more responsive to higher powers. In Judaism, Yom Kippur is a day of complete fasting (including not drinking water!) and is considered the holiest day of the year. In Islam, Ramadan is a 28- to 30-day fast, during which food and drinks are not permitted during daylight hours.

In Christianity, Lent, the 40 days leading up to Easter, and Advent, the time leading up to Christmas, both started as times of fasting, introspection, and prayer. In Native American tribes, fasting was practiced before and during a vision quest; the Pueblo people fasted before major ceremonies performed during the change of seasons; shamans believed that fasting allowed them to see their visions more clearly and to control spirits. In ancient Greece, it was thought that eating food increased the risk that demonic forces could enter your body, so the Greeks fasted often. In India, Jainism has various fasting traditions, including not eating to satiation in daily life. The list could go on ad infinitum.