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I want to tell you something a little embarrassing.
When I picked up Good Energy by Dr. Casey Means, I thought I already knew most of it.
I have been a voracious reader of health and wellness content since my late thirties. I have a continuous glucose monitor on my arm. I track my HRV, my sleep architecture, my body composition, my VO2 max. I supplement thoughtfully, I exercise intentionally, and I have read more books about nutrition and longevity than most people will encounter in a lifetime. I approached this book the way a reasonably well-informed person approaches a topic they have studied — curious, sure, but not expecting to be fundamentally rearranged.
I was wrong. Embarrassingly, completely, productively wrong.
Two chapters in, I put the book down, looked at the ceiling for a few minutes, and thought: I do not actually know very much about any of this.
That moment of humility is where this Good Energy book review really begins.
What I Thought I Knew About Health (Spoiler: Not Much)
Here is the honest version of my wellness education before Casey Means got hold of me.
I had watched the diet world cycle through its obsessions for decades. Low fat was going to save us all. Then no fat. Then fat was fine but carbs were evil, which gave us Atkins, which gave us keto, which gave us carnivore, which gave us… confusion. I watched these dietary philosophies arrive with great fanfare, contradict each other at a cellular level, get built on studies that were poorly designed and often industry-funded, and then quietly get replaced by the next thing.
The cabbage soup diet. South Beach. Paleo. Whole 30. Each one arrived with passionate advocates who had genuinely gotten results, and each one eventually got complicated by the fact that humans are not identical and nutrition science, it turns out, is hard.
I had absorbed enough of this over the years to feel informed. I was not uninformed, exactly. I just did not have the foundational framework that would have made all of it make sense — or not make sense — at the right level.
Casey Means gave me that framework. And it starts somewhere almost nobody starts: inside your cells.
The Thing Nobody Ever Explained to Me
Good Energy is built on a premise that sounds almost too simple once you hear it, and yet I had never heard it stated this clearly in forty years of reading about health.
Every chronic condition that plagues us — heart disease, type 2 diabetes, Alzheimer’s, depression, anxiety, certain cancers, chronic fatigue, hormonal chaos, the relentless inflammation that makes everything harder — shares a common root. Not a contributing factor. A root. And that root is mitochondrial dysfunction: cells that have lost their ability to produce energy efficiently.
When your mitochondria are working well, you have what Means calls good energy. Your body creates cellular fuel efficiently, inflammation stays low, hormones regulate properly, your brain functions clearly, and your immune system does its job. When your mitochondria are struggling — damaged by the wrong foods, by chronic stress, by poor sleep, by environmental toxins, by a sedentary lifestyle — you have bad energy. And bad energy does not just make you tired. It creates the inflammatory cascade that eventually becomes the diagnoses nobody wants.
I read this sitting in my wellness room with a continuous glucose monitor on my arm, and I watched in real time exactly what she was describing. A meal would go in. My glucose would spike or hold steady depending not just on what I had eaten, but on whether I had moved afterward, how well I had slept the night before, and how much stress I had carried into the meal. She was not theorizing. I was watching the proof on my wrist.
This is not a book about dieting. This is a book about the operating system underneath everything else.
Why This Book Hits Differently After 50
I want to speak to you specifically if you are in your 50s or 60s and you have had the creeping sense that your body is no longer playing by the old rules.
The things that worked before do not work the same way anymore. You eat the way you always ate and the scale does not respond. You exercise and recover more slowly. You sleep but wake up tired. Your energy is inconsistent in ways it never was before. You mention this to your doctor and get told it is just aging, which is technically true and also completely unhelpful.
What Casey Means explains, and what I found genuinely revolutionary, is that what we experience as “just aging” is largely accelerated mitochondrial dysfunction. The good news — and there is real good news here — is that mitochondria are remarkably responsive to lifestyle inputs. They are not fixed. They are dynamic. You can improve their function at any age, and the changes show up relatively quickly in measurable ways.
Between September 2025 and April 2026, following the principles in this book alongside other intentional lifestyle changes, my metabolic age dropped from 69 to 61 — eight years in seven months. I lost 19 pounds. My body fat dropped 6.7 percent. My visceral fat went from elevated to low risk. I am not presenting these numbers as a before and after advertisement, because my results involved more than one book and more than one intervention. But I am presenting them as evidence that this framework, taken seriously and applied consistently, moves the needle on things that actually matter.
The Part Where I Tell You Casey Means Goes Pretty Far
Here is the honest part of this Good Energy book review that most reviews leave out, probably because they are trying to be polite.
Some of Casey Means’ recommendations are extreme. Not wrong — extreme. And I say this as someone who has adopted a meaningful portion of what she suggests and experienced real results from doing so.
She recommends filtering your shower water. Replacing all your plastics. Overhauling your personal care products and makeup to eliminate endocrine-disrupting chemicals. Radical changes to light exposure, including avoiding artificial light after dark and getting outside within thirty minutes of waking regardless of weather. She recommends tracking glucose, sleep, heart rate variability, and a panel of biomarkers that most doctors do not routinely test.
I have not done all of this. I have not thrown out all my plastics. I have not replaced my makeup collection. I have not swapped every personal care product for a cleaner version.
What I have done is install an AquaTru reverse osmosis filter in my kitchen and run that water through my ice maker and my coffee maker every single morning. I have significantly cleaned up my eating, not perfectly but substantially. I take a post-meal walk almost every day, which I started because I watched my own glucose curve flatten in real time when I moved after eating. I pay attention to sleep in a way I never did before. I have built what I think of as a modular stack — not Casey Means’ full protocol, but the pieces of it that made the most sense for my actual life and that I could genuinely sustain.
This is the approach I would recommend to you. Not all or nothing. Not the full overhaul or nothing. Just start with the pieces that feel most accessible and build from there. The science behind the framework is sound even if you implement it imperfectly. Imperfect implementation of a correct framework beats perfect implementation of a wrong one every single time.
What Good Energy Actually Changed For Me
Beyond the numbers, which matter, here is what changed in how I live and think.
I no longer think about food primarily in terms of calories or even macronutrients. I think about it in terms of what it does to my cells. That shift sounds subtle and is actually enormous. When you understand that ultra-processed food does not just add calories but actively damages mitochondrial function, you stop thinking about whether something is “worth the calories” and start thinking about whether it is worth the cellular cost. Those are different questions and they lead to different decisions.
I understand why chronic stress is not just emotionally exhausting but metabolically destructive. Cortisol, released in response to sustained stress, directly impairs mitochondrial function. This is why the weeks when work is hardest are also the weeks when everything else feels harder. It is not a coincidence. It is biology.
I understand why sleep is not a lifestyle preference but a metabolic necessity. During sleep, your cells do the repair work that good energy production requires. Shortchange sleep consistently and you are shortchanging your mitochondria, which eventually shortchanges everything else.
And I understand, finally, why the diet wars never had a winner. Because they were all fighting over the wrong question. The question is not which macronutrient to restrict. The question is what creates healthy mitochondrial function — and almost everything that answers that question well happens to also involve eating real food, moving regularly, sleeping adequately, and managing stress. The specifics matter less than the framework, and the framework was hiding in plain sight at the cellular level the whole time.
Who Should Read Good Energy
Everyone. But specifically:
If you are a woman over 50 who is tired of being told that how you feel is just aging, this book will give you a different story and the tools to test it.
If you have a chronic condition — fatigue, insulin resistance, high blood pressure, autoimmune issues, depression that does not fully respond to treatment — and you have never looked at it through a metabolic lens, this book will open a door you did not know was there.
If you are reasonably healthy and want to stay that way for the next thirty years in a way that involves genuine vitality rather than just the absence of diagnosis, this is the operating manual.
And if you, like me, thought you already knew most of what there was to know about your own health — read it anyway. The humbling is worth it.
A Final Word
Casey Means wrote this book after losing her mother to pancreatic cancer and deciding that the medical system she had trained inside was better at treating symptoms than preventing the conditions that made treatment necessary in the first place. That motivation is visible on every page. This is not a detached clinical summary. It is a deeply personal argument made by someone who believes your health is recoverable and your energy is not fixed.
She is right. I have the numbers to prove it. And more importantly, I have the daily lived experience of a body that functions better than it did eight months ago, which at 61 is not something I take lightly or for granted.
You can find Good Energy wherever books are sold. I bought my copy on Amazon and have since recommended it to more people than I can count. If you read it and want to talk through how to build your own modular approach — the version that works for your real life rather than an idealized protocol — come find me in the comments. That conversation is exactly what this community is for.
It is the most practically useful book on my best self-help books for women over 50 list, which is saying something for a CFO who reads everything with a yellow highlighter and a skeptical eye.
