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Fast this way
What It’s About
*A Fast This Way* is a fascinating read on the latest thoughts about fasting, and it gives readers the toolkit to get the most out of their fasts and personal biology.
Three Key Ideas
Hunger vs. Craving
Fasting teaches you to tell apart a real biological hunger signal from a craving engineered by processed food and habit.
Cellular Repair Mechanisms
Going without food triggers autophagy, raises NAD-plus, and improves stem cell regeneration in ways constant eating never allows.
Metabolic Flexibility
Rotating fasting protocols train the body to switch between glucose and ketones on demand, the real long-term prize of any fasting practice.
Read a Sample
A burned-out Silicon Valley entrepreneur sits cross-legged in a red-rock cave near Sedona, water bottle at his side, watching a bald eagle feather drift across the floor. He weighs three hundred pounds at his worst. He has Hashimoto's thyroiditis from mold exposure, brain fog he can taste, and a Wharton MBA he earned while running on four hours of sleep a night. The shaman who drove him here in a beat-up pickup told him only two things: do not talk to the other seeker camping a mile away, and keep your phone off except for one minute each morning. He has no food for four days. And for the first time in his adult life, he is about to stop confusing hunger with craving.
This is the opening Dave Asprey returns to throughout Fast This Way, and it is the right starting point, because the book is not really about food. It is about the gap between a biological signal and the story you tell yourself about that signal. Asprey wants you to learn that gap. Everything else (the butter coffee, the supplement stack, the protocols for women in perimenopause) flows from that single insight. Hunger is information. Craving is a hostage situation. Fasting is how you find out which one you are dealing with.
Chapter 1: Fasting Lives in Your Head
Asprey defines fasting as "going without," and immediately pushes the definition past food. Sobriety is going without substances. Meditation is going without thinking. The Sabbath is going without work. Hypoxic training is going without oxygen, the way endurance athletes prepare in Albuquerque and Chamonix. Cameron Sepah, a psychologist at UCSF, coined the dopamine fast, which means going without instant gratification: shopping, gaming, alcohol, the bottomless scroll. Asprey himself gave up television during his MBA and never bought another. By his rough count, that has saved him a few thousand dollars and many thousands of hours.
Who It’s For
- Anyone who wants to lose weight without the hunger and misery of calorie restriction.
- Anyone who is curious about autophagy, ketosis, and the science behind why fasting works.
- Anyone who struggles with food cravings and wants practical tools to break the cycle.
- Anyone interested in improving energy, sleep, and mental clarity through lifestyle changes.
About the Author: Dave Asprey
Dave Asprey is an entrepreneur and biohacker best known for founding Bulletproof and popularizing Bulletproof Coffee, a blend of black coffee, grass-fed butter, and MCT oil. He has written several books on diet, performance, and longevity, drawing on his own experience reversing serious health problems including obesity and cognitive decline caused by toxic mold exposure.
Asprey approaches nutrition and fasting as an engineer rather than a clinician, combining peer-reviewed research with extensive self-experimentation. He founded the 40 Years of Zen neurofeedback program and hosts the long-running Bulletproof Radio podcast, where he interviews scientists, doctors, and researchers on health optimization.
