Book SummaryFast This Way, by Dave Asprey

1-Page Summary1-Page Book Summary of Fast This Way

Many people think the primary benefit of intermittent fasting—cycling between periods of eating and not eating—is weight loss. But in Fast This Way, Dave Asprey argues it offers far more—and more important—benefits: Fasting transforms you into your best self by optimizing how your mind and body function and helping you gain a sense of control over your life.

Asprey acknowledges that going without food can be challenging, so he’s created an approach to intermittent fasting that reduces its difficulty while making it more enjoyable—“Bulletproof Intermittent Fasting.” By following Asprey’s fasting advice, you...

Fast This Way Summary What Is Fasting?

Asprey defines fasting as a deliberate choice to abstain from something you feel dependent on. He explains that we all have needs, cravings, and addictions that impact our actions and decisions, causing us anxiety when we’re deprived of them. Fasting helps you break free from these attachments. Throughout this guide, we’ll focus on a specific form of fasting from food called intermittent fasting. However, Asprey adds that you can fast from practically anything—from social media to negativity to video games—and reclaim a sense of power and control in your life.

(Shortform note: In The Willpower Instinct, Kelly McGonigal explains the neuroscience behind why we become addicted to things like food and video games: Our brain produces a chemical called [restricted term] that controls our desires and motivates us to seek immediate pleasures, making us excited, for instance, when we see something rewarding (like a tasty snack). This mechanism helped our ancestors survive by motivating them to hunt and gather food. But it...

Fast This Way Summary The Benefits of Fasting

According to Asprey, eating the way your body was designed to eat—as intermittent fasting allows you to do—has benefits for your physical health, mental health, and overall strength and fitness. In this section, we’ll look at each of these benefits in more detail.

Fasting Promotes Weight Loss

Asprey writes that fasting helps you lose weight by switching your body’s energy source from glucose to fat. When you fast, your body runs out of glucose from food, so it starts burning fat instead. It converts your fat into energy molecules called ketones, which also suppress your hunger. When your body burns fat as its primary energy source, you’re in a state called ketosis.

(Shortform note: When you stop consuming glucose, it takes some time before your body starts burning fat as its primary fuel source. In The Obesity Code, Jason Fung says ketosis kicks in after two to three days of fasting.)

Asprey argues that, unlike fasting, dieting is ineffective because it relies on the flawed concept of calories-in-calories-out (CICO). This concept...

Fast This Way Summary Tips for Intermittent Fasting

Now that we’ve discussed the many benefits of fasting, we’ll look at how you can start intermittent fasting. According to Asprey, one of the biggest obstacles people face when they start to fast is the psychological struggle of going without food. However, he argues that fasting doesn’t have to be a struggle. It can actually be enjoyable and easy—the secret is learning how to avoid hunger pangs. To do this, Asprey presents a simple and effective way to keep hunger pangs at bay while you fast: In the morning, drink a special blend of coffee, grass-fed butter, and a teaspoon or two of C8 MCT oil.

Asprey calls this blend Bulletproof Coffee, and he maintains that the combination of these ingredients allows you to enjoy all the benefits of fasting without feeling hungry. Here’s how each of the ingredients works:

• Black coffee: Provides caffeine, which doubles your ketone production. Higher ketone levels reduce your hunger by suppressing a hormone called ghrelin which stimulates your appetite.
• Grass-fed butter: Provides high-quality fats that keep you satiated while still allowing your body to burn fat and undergo autophagy.
• C8 MCT oil: Unflavored coconut...

Shortform Exercise: Plan for Your Next Intermittent Fast

According to Asprey, if you follow the right approach, intermittent fasting can be an enjoyable experience that can provide you with a host of benefits. In this exercise, reflect on your goals and plan for a successful fast.

Reflect on your current eating habits and how they make you feel. How much of it is dictated by societal norms (like eating three meals a day) as opposed to your body’s needs?