Casey Means trained as a head and neck surgeon at Stanford, then walked away from surgery after concluding that the conditions she was operating on — cancer, chronic inflammation, cardiovascular disease — were largely preventable dietary and lifestyle diseases that medicine had no interest in preventing. Good Energy is the book that resulted: a metabolic health manifesto built around the mitochondria and a damning critique of how modern food, medicine, and technology conspire to make Americans sick.
What Is This Book?
Means argues that the common thread running through virtually all chronic disease — from obesity and diabetes to depression, infertility, and Alzheimer’s — is mitochondrial dysfunction: cells that can no longer efficiently produce energy from food. She calls this “bad energy,” and traces it to ultra-processed food, sedentary behaviour, poor sleep, chronic stress, and environmental toxins. “Good energy,” conversely, is what happens when mitochondria work well — robust cellular energy production that manifests as stable mood, clear thinking, physical vitality, and long-term health. The book outlines a protocol for restoring metabolic function through diet, movement, sleep, and continuous glucose monitoring (CGM).
The Metabolic Health Framework
The strongest chapters are those detailing what Means calls the “five metabolic lab markers” — fasting glucose, fasting insulin, triglycerides, HDL cholesterol, and waist circumference — and arguing that doctors should screen for metabolic dysfunction using these markers routinely, rather than waiting for the clinical thresholds of diabetes or cardiovascular disease to be crossed. She presents data showing that the majority of American adults are metabolically unhealthy by optimal (not clinical) standards, and that this preclinical dysfunction is driving the chronic disease epidemic.
We have medicalised the symptoms of metabolic dysfunction while ignoring the root cause. The mitochondria don't lie — and our food system has been systematically destroying them for fifty years.
— Casey Means, Good Energy
What Makes It Stand Out
Means writes with an urgency and clarity that most physician-authors lack. She is unafraid to name names — specific food companies, pharmaceutical manufacturers, regulatory agencies — and to connect their financial incentives to public health outcomes. The CGM (continuous glucose monitor) section is one of the best practical introductions to real-time metabolic feedback available, explaining how to use glucose data to understand individual responses to different foods, sleep, stress, and exercise. She also covers postbiotic short-chain fatty acids, circadian biology, and seed oil controversy with more nuance than most popular treatments.
6 Key Ideas From This Book
Means traces virtually all chronic disease to mitochondrial dysfunction — cells unable to produce clean energy from food. Restoring mitochondrial health, she argues, resolves downstream symptoms across multiple organ systems.
Fasting glucose, fasting insulin, triglycerides, HDL, and waist circumference reveal metabolic health long before clinical disease develops. Means argues these should be standard screening tools for everyone over 20.
CGM devices give real-time feedback on how individual foods, sleep quality, stress, and exercise affect blood sugar. This personalised data is more actionable than any population-level dietary guideline.
Seed oils, refined carbohydrates, and ultra-processed foods damage mitochondria through oxidative stress, inflammatory signalling, and microbiome disruption — not merely by providing excess calories.
Metabolic health is not just about food — consistent sleep timing, morning light exposure, and avoiding late-night eating are essential for mitochondrial function and glucose regulation.
The food industry, pharmaceutical companies, and medical education system have intertwined financial incentives that actively discourage prevention-focused, food-based medicine. Means names specific examples throughout.
Any Weaknesses?
Means’s institutional critique, while often well-supported, occasionally slides into broad strokes that flatten important distinctions between corporate actors, regulators, and individual practitioners. The CGM advocacy, while fascinating, also involves tools that are expensive and inaccessible to most people — a limitation she acknowledges but doesn’t fully resolve. Some readers will find the tone evangelical; Means writes with the zeal of a convert, which energises the narrative but sometimes crowds out nuance.
Who Should Read This?
Anyone struggling with energy, mood, or weight issues who wants a mechanistic explanation rooted in metabolic science rather than calorie counting or willpower narratives.
Outlive by Peter Attia for a more individualized longevity framework, or Metabolical by Robert Lustig for a deeper dive into fructose and processed food biochemistry.
Psychiatrists and mental health providers — Means devotes significant space to the metabolic roots of anxiety, depression, and cognitive decline, with compelling evidence that dietary intervention can improve mental health outcomes.
A confrontational institutional critique and CGM recommendations that require purchasing wearable technology. The book is most useful to readers who can engage with both the science and the systemic analysis without dismissing either.
Frequently Asked Questions
Is Good Energy worth reading?
Good Energy is one of the most important metabolic health books published in the past five years — urgent, well-researched, and practically actionable. Means combines personal story, cellular biology, and systemic critique in a way that is rare in health writing. Essential reading for anyone serious about understanding why chronic disease is the defining health crisis of our time.
Who should read Good Energy?
Anyone struggling with energy, mood, or weight issues who wants a mechanistic explanation rooted in metabolic science rather than calorie counting or willpower narratives.
What is Good Energy about in one sentence?
Casey Means trained as a head and neck surgeon at Stanford, then walked away from surgery after concluding that the conditions she was operating on — cancer, chronic inflammation, cardiovascular disease — were largely preventable dietary and lifestyle diseases that medicine had no interest in preventing.
The Verdict
Good Energy is one of the most important metabolic health books published in the past five years — urgent, well-researched, and practically actionable. Means combines personal story, cellular biology, and systemic critique in a way that is rare in health writing. Essential reading for anyone serious about understanding why chronic disease is the defining health crisis of our time.
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