I know what you might be thinking: Why do I need a cookbook to show me what to eat when I’m fasting? It’s a perfectly valid question. After all, fasting is about not eating—so why do you need to cook anything?
Not so long ago, I also thought that “fasting” meant not eating anything. You merely stopped having food at one point, and started eating it again at another point, with nothing but water, or perhaps a cup of coffee with coconut oil, or a bowl of broth, or vegetable juice passing between your lips in the meantime. But then I began carefully studying this topic and collaborating with researchers and clinicians who have been investigating and implementing the therapeutic practice of fasting. I started to see that while true fasts—where you consume no solid food for a specific period of time—did offer some profound health benefits, they could also expose you to some perils.
This journey I’ve been traveling has shown me that fasting and health are, in many ways, very similar to exercise and fitness. Just as you wouldn’t get up from the couch and head outside to run a marathon on your first outing, you need to work your way up to going without food—particularly if you have been eating the way most Americans do. That is to say, relying on heavily processed, carbrich foods and eating at all hours of the day and night. These eating habits have trained your body to burn glucose as your primary fuel, which leaves you exposed to increased free radical damage, insulin resistance, and nutritional deficiencies. All of these, in turn, make it harder for you to reap the therapeutic benefits of fasting.
While fasting can and does cue your body’s innate healing response, causing metabolic and cellular changes that support optimal health, it can also release chemicals and other toxins that have been safely tucked away in your fat cells. When you curtail your food intake, you enter a fasted state, which means that your body has to turn to its stores of energy for fuel, and you encourage your body to switch from burning glucose (which is derived from the carbohydrates and, to a lesser extent, the proteins you eat) to burning fat for fuel. In a fasted state, the fat that is burned comes from your fat stores. In addition to the energy that is released from the fat, the toxins that were stored in your fat cells can enter your bloodstream and wreak havoc on your body, likely contributing to many of the side effects people commonly experience when fasting, such as headaches, brain fog, and nausea.
Fat tissue has been shown to be a virtually limitless storage closet for fat-soluble toxins known by the classification persistent organic pollutants (POPs).1 Once stashed away, POPs can affect the quality and quantity of overall fat tissue, making it easier to gain and harder to lose fat. POPs can also contribute to overall inflammation in your body, which has many negative effects on your metabolism and your overall health.
Multiple studies have shown that loss of fat tissue—either due to changes in your diet or from bariatric surgery—results in an increase of POPs in your blood.2, 3 While your body does have the capability to process and eliminate these toxins once they are liberated—in fact, weight loss has been shown to reduce the total POP body burden for certain contaminants by 15 percent4—a sudden influx of toxins released from your fat cells can easily overwhelm your systems of detoxification, resulting in even greater damage.
What the vast majority of people need is a gradual approach to fasting, in which you thoughtfully change your habits—both what you eat and when—and acclimate yourself gently to the state of being able to burn fat for fuel. At the outset, you start intermittent fasting (reducing the window time during which you eat) and begin following a cyclical ketogenic diet (a high-fat, low-net-carb, moderate-protein diet, like the one I outlined extensively in my book Fat for Fuel). You’re compressing your eating window to six to eight hours, while limiting your carbs and proteins and replacing the missing calories with high-quality fats.
Once you are metabolically flexible and able to burn fat as your primary fuel, then you can begin to add in one day a week of a partial fast—where you consume 300 to 600 calories (depending on your lean body mass) that provide the nutrients your body needs to detox effectively. Ideally you consume these calories in one single meal after your 16- to 18-hour intermittent fast ends, and then your next meal is 24 hours later. After 24 hours you have a full day of food with extra carbs and protein to supply the fuel for all the rebuilding that will be occurring in your cells as they start to regenerate after the partial fast. I call this plan KetoFasting, and it enables you to reap the benefits of fasting while minimizing the downsides.
To make KetoFasting as supportive of detoxification as possible, I have read hundreds of studies to get a better understanding of the nutrient-dense foods and supplements that are best for facilitating the process that carries harmful substances out of your body. And to make these foods as delicious as possible, I reached out to chef, restaurateur, and my collaborator on the Fat for Fuel Cookbook, Pete Evans, to create recipes that will provide the calories for your partial-fast days.
I gave Pete the nutritional parameters for the low-calorie meals that are appropriate for the days you do a partial fast, and he developed more than 40 recipes that follow those guidelines so that you have access to a variety of delicious options for the days when you are partially fasting.
For a much more complete guide to cyclical ketosis, refer to Fat for Fuel and the Fat for Fuel Ketogenic Cookbook. For a deeper dive into KetoFasting, see the companion to this cookbook, KetoFast. And because I am continually educating myself and refining my approach to health, be sure to sign up for my e-mail newsletter at mercola.com. When you do, you’ll receive the coverage of my interviews with top researchers and practical advice for implementing their findings in your life.
It is my hope that the information on these pages you hold in your hand, as well as my other recent titles (and e-mail newsletters), will help you find your optimal level of health, and that the recipes included here will help you enjoy, and even look forward to, your fast days.
