What Is Health?

What Is Health?

Allostasis and the Evolution of Human Design

By Peter Sterling

An argument that health is optimal responsiveness and is often best treated at the system level.





An argument that health is optimal responsiveness and is often best treated at the system level.

Medical education centers on the venerable “no-fault” concept of homeostasis, whereby local mechanisms impose constancy by correcting errors, and the brain serves mainly for emergencies. Yet, it turns out that most parameters are not constant; moreover, despite the importance of local mechanisms, the brain is definitely in charge. In this book, the eminent neuroscientist Peter Sterling describes a broader concept: allostasis (coined by Sterling and Joseph Eyer in the 1980s), whereby the brain anticipates needs and efficiently mobilizes supplies to prevent errors.

Allostasis evolved early, Sterling explains, to optimize energy efficiency, relying heavily on brain circuits that deliver a brief reward for each positive surprise. Modern life so reduces the opportunities for surprise that we are driven to seek it in consumption: bigger burgers, more opioids, and innumerable activities that involve higher carbon emissions. The consequences include addiction, obesity, type 2 diabetes, and climate change. Sterling concludes that solutions must go beyond the merely technical to restore possibilities for daily small rewards and revivify the capacities for egalitarianism that were hard-wired into our nature.

Sterling explains that allostasis offers what is not found in any medical textbook: principled definitions of health and disease: health as the capacity for adaptive variation and disease as shrinkage of that capacity. Sterling argues that since health is optimal responsiveness, many significant conditions are best treated at the system level.


$30.00 X ISBN: 9780262043304 264 pp. | 6 in x 9 in 62 b&w illus.


  • “Peter Sterling is a preeminent neuroscientist whose revolutionary work on allostasis has advanced our understanding of the brain and its functional architecture. What Is Health? continues that profound work of scholarship and prompts serious reflection as to how we deliver care and train the next generation of health care providers.”

    Katrina Armstrong

    Physician-in-Chief, Massachusetts General Hospital

  • “This lucid story on the wisdom of the human body and the poverty of our attempts to control it has deep implications for how we go about living our lives in the present crisis of persons and the planet. A wonderful and worried homage to Homo sapiens.”

    Tor Nørretranders

    author of The User Illusion and The Generous Man

  • “The eminent and far-sighted neuroscientist takes a step away from the buzz and confusions of modern life and goes back to first principles. He suggests that we should take brain function to define our goals and make the economic and political decisions necessary to achieve them. When properly understood, the brain tells us what is good for us, whereas our sometimes unreflected choices can lead us into wrong, and ultimately fatal, directions. A wonderful and very consequential book.”

    Wolfram Schultz

    University of Cambridge, Brain Prize 2017

  • “Peter Sterling leads us on a deep history tour of ourselves, from single cells to the evolution of Homo sapiens. Understanding the ways bodies adapt to their environment yields one startling insight after another. You will never look at disease, addiction, and health the same way again.”

    Keith Payne

    author of The Broken Ladder; Professor and Director of Graduate Studies, Department of Psychology and Neuroscience, University of North Carolina, Chapel Hill