With fasting at an all-time high in popularity, here is the first deep exploration into the surprising history and science behind the practice—essential to many religions and philosophies.

Whether for philosophical, political, or health-related reasons, fasting marks a departure from daily routine. It involves doing less but doing less in a radical way. Based on extensive historical, scientific, and cultural research and reporting, The Fast illuminates the numerous facets of this act of self-deprivation. John Oakes interviews doctors, spiritual leaders, activists, and others who guide him through this practice—and embarks on fasts of his own—to deliver a book that supplies readers curious about fasting with profound new understanding, appreciation, and inspiration.

In recent years, fasting has become increasingly popular for a variety of reasons—from health advocates who see fasting as a method to lose weight or to detox, to the faithful who fast in prayer, to seekers pursuing mindfulness, to activists using hunger strikes as an effective means of peaceful protest. Notable fasters include Moses, Buddha, Jesus, Muhammad, Gandhi, George Washington, Abraham Lincoln, Emily Dickinson, Mark Twain, Cesar Chavez, and a long list of others who have drawn on its power over the ages and across borders and cultures.

The Fast looks at the complex science behind the jaw-dropping biological phenomena that occur inside the human body when we fast. Metabolic switching induced by fasting can prompt repair and renewal down to the molecular level; such fasting can provide benefits for those suffering from obesity and diabetes, cancer, epilepsy, cardiovascular disease, neurodegenerative disorders, and more. Prolonged fasting can serve both to reinvigorate the immune system and to protect it against damage. Beyond the physical experience, fasting can be a great collective unifier, an instant leveler that connects us purely by virtue of being an act accessible to all, and it has been adopted by religions and political movements all over the world for millennia. Fasting is central to holy seasons and days such as Lent (Christianity), Ramadan (Islam), Yom Kippur (Judaism), Uposatha (Buddhism), and Ekadashi (Hinduism). On an individual level, devout ascetics who master self-deprivation to an extreme are believed to be closer to the divine, ascending to enlightenment or even sainthood.

Through the ages, fasting in the name of justice—a hunger strike—has signaled purity of intent and action. It’s a tactic that demands commitment, serves to highlight the cruelty of those in authority, and appeals to shared values: that we’re united by a common humanity and we deserve to be heard. Advocates who have waged hunger strikes include Gandhi in India, Bobby Sands in Ireland, and the Taxi Workers Alliance in New York City.

Fasting reminds us of the virtues of holding back, of not consuming all that we can. Ultimately, this book shows us that fasting is about much more than food: it is about taking control of your life in new and empowering ways and reconsidering your place in the world.