The Dr. Fitz Metabolic Longevity Protocol
A four-pillar system for body composition, metabolic optimization, and healthy aging — built on clinical nutrition, fitness strategy, targeted supplementation, and lifestyle intervention.
Book a Free 10-Minute Discovery CallDr. Michael Fitzmaurice, MD · Physician, Exercise Physiologist & Author · Anti-Aging & Regenerative Medicine Physician
Most fat loss programs treat the scale as the goal. That's why people end up smaller, weaker, and worse off.
In my consultations, I see the same pattern over and over. Someone in their late 30s, 40s, 50s — sometimes earlier — comes to me having tried four or five diets. Keto, intermittent fasting, calorie counting, maybe a coach off Instagram. They lost weight. Then they gained it back. Then they tried again. Each cycle left them with less muscle, slower metabolism, and worse blood sugar than the round before.
This is what happens when fat loss is treated as a number on the scale instead of a body composition outcome. Losing weight is easy. Losing fat while preserving muscle — especially as you age — is a completely different problem. It requires food, training, and the underlying physiology to all move in the same direction.
I'm also seeing this happen earlier than ever. People in their late 20s and early 30s are showing up with insulin resistance, stubborn fat that won't move, and metabolic markers that used to be reserved for middle age. The earlier you address it, the easier the protocol works.
Body composition is only half of it. The other half is what's happening underneath: insulin sensitivity, mitochondrial function, inflammation, hormonal signaling. These are the systems that decide whether you age into your 70s vital and strong — or fragile and on six medications.
The Dr. Fitz Metabolic Longevity Protocol is built to address both layers at once. Body composition above. Metabolic health below. Four pillars working together to optimize how you look, how you feel, and how you age.
Four pillars. One system.
The foundation of body composition and metabolic health.
Macronutrient strategy calibrated for fat loss with muscle preservation. Protein targets that protect lean mass during a caloric deficit — not arbitrary numbers from a fitness app. Blood sugar management. Anti-inflammatory eating. A sustainable framework, not a crash diet or a tribal eating philosophy.
This is the pillar that does the most heavy lifting. People underestimate it constantly. Nothing else in the protocol works if nutrition isn't dialed in.
Resistance training is non-negotiable.
Resistance training is the only intervention that protects muscle while you're losing fat — and muscle mass is the single strongest predictor of how well you'll age into your 60s, 70s, and 80s.
The protocol covers resistance training programming, cardiovascular conditioning, and recovery — calibrated to your current fitness level, your time, and your equipment. Whether you've never lifted a weight or you've been training for decades, the structure adapts. This pillar is where my Exercise Physiology training does the work.
The mitochondrial and metabolic foundation layer.
The supplementation layer of the protocol supports the foundational pathways — mitochondrial energy production, methylation, oxidative balance, and metabolic inflammation. These are the same pathways that drive body composition, energy production, and how well we age at the cellular level.
I personally use NeuroAxis® as part of my own anti-aging protocol. The formula was originally developed for peripheral nerve recovery, but mechanistically it's a mitochondrial and metabolic foundation stack — built around the same ingredients used across longevity medicine and exercise physiology for decades: R-Alpha Lipoic Acid, Acetyl-L-Carnitine, CoQ10, methylated B-vitamins, NAC, and an anti-inflammatory triad.
The foundation everything else stands on.
Sleep, stress, alcohol, daily movement, and recovery. These aren't optional add-ons — they are direct inputs to body composition and metabolic health. Sleep less than seven hours and insulin sensitivity drops measurably the next day. Manage stress poorly and cortisol rewrites your fat distribution. Drink too much and fat loss stalls regardless of how clean your diet is.
Get this pillar wrong and the other three compound less. Get it right and everything else accelerates.
The pillars aren't a checklist. They're a closed loop.
Each pillar reinforces the other three.
When all four pillars run at once, the system changes. Body composition shifts measurably. Energy stops crashing at 3 PM. Sleep deepens. Blood markers improve. The mirror starts catching up to the work.
This is the system I walk people through in consultation. It's not a quick fix and it's not a guarantee. It is the framework I've watched work — over and over — when people commit to all four pillars instead of cherry-picking the one that sounds easiest.
The four-pillar system is built for adults serious about looking, feeling, and aging well.
Strongest Fit
Also Supports
The protocol is built for adults who want more than just "not sick." They want to look strong, feel strong, and age into their 60s, 70s, and 80s with the energy and physical capability of someone a decade younger.
The earlier you start, the easier the protocol works. But it works at any age — the only requirement is that you're serious about the four pillars together, not just the one that sounds easiest.
If you're not sure whether your situation fits, that's exactly what the free discovery call is for. We'll spend ten minutes on it, and we'll both know by the end.
Three ways to start. Pick the one that matches where you are.
Take the Free Assessment
Lowest friction
A short clinical self-assessment that helps you understand where you stand on metabolic health and body composition risk factors. Takes about five minutes. Free, no booking required.
Take the Free AssessmentBook a Free 10-Minute Discovery Call
For full protocol fit
We'll spend ten minutes on your situation, your history, what you've tried, and what your goals actually are. By the end of the call, you'll know whether the protocol fits your case — and if it does, what the next step looks like.
Book Your Free Discovery CallStart with the Ebook
For the entry-level read
Why Fat Loss Stalls After 40 — the $14 ebook covers the metabolic and physiological reasons fat loss gets harder with age, and the foundational shifts that actually move the needle. A low-commitment way to see how I think before booking a call.
Get the $14 EbookDr. Michael Fitzmaurice, MD
I built the Dr. Fitz Metabolic Longevity Protocol because almost no clinician on the internet has all the pieces stacked in one place.
Most longevity doctors don't have a foundational background in exercise physiology — so the fitness pillar of their protocols gets outsourced or skipped entirely. Most fitness coaches don't have the clinical training to actually understand what's happening in someone's metabolic and hormonal physiology. And most physicians treating metabolic disease aren't trained in anti-aging medicine or body composition science.
I sit at the intersection of all three. The protocol is what happens when you combine an MD, a surgical career that taught me how the human body actually fails over time, an undergraduate degree in exercise physiology, a master's in biomedical science, and certification in anti-aging medicine — and then you build a single system around what consistently moves the needle for adults trying to age well.
What people ask before booking
Do I have to follow a specific diet?
No. The protocol works around your food preferences, your culture, your schedule, and what you'll actually sustain. There's no mandatory keto, no mandatory fasting, no mandatory anything. The protocol gives you a macronutrient and metabolic framework — we tailor the food itself to your life on the consultation.
What if I haven't worked out in years?
That's the default starting point for most people I work with. The fitness pillar is calibrated to where you are, not where someone on Instagram is. We start with what your body can actually handle this week and build from there. Resistance training is the priority — not running marathons.
Do I need a gym?
No. The protocol adapts to home equipment, a basic gym membership, or a fully-equipped commercial gym. The principles are the same. The equipment is the variable.
How fast will I lose weight?
This is the question I push back on. The right question is body composition — how much fat are you losing while preserving or building muscle. A proper rate is 0.5–1% of body weight per week in fat loss for most adults, with muscle maintained. That's not what Instagram promises. It's what actually works long-term and doesn't wreck your metabolism in the process.
Is this safe if I have insulin resistance or pre-diabetes?
The protocol is specifically built to address insulin resistance and pre-diabetic blood sugar — these are exactly the conditions it targets. That said, the protocol runs alongside your existing medical care. I always recommend keeping your primary physician in the loop, especially if you're on medication.
I'm in my late 20s — is this overkill for me?
The opposite. The earlier you build the foundation, the easier everything is for the next four decades. People in their late 20s and 30s who do the protocol now avoid almost every problem the people in their 50s come to me with. Earlier is easier.
What does the full protocol cost?
The discovery call is free. The ebook is $14. Paid consultation pricing depends on whether you need a single session or a longer-term plan — that gets discussed on the discovery call once we know what you're working with.
Ten minutes. We'll know if this is right for you.
The discovery call is the lowest-friction way to figure out whether the Dr. Fitz Metabolic Longevity Protocol fits your situation. No pressure. No pitch. If it's a fit, we'll talk about next steps. If it's not, I'll tell you straight — and point you toward what is.
Book Your Free 10-Minute Discovery CallDr. Michael Fitzmaurice, MD · Physician, Exercise Physiologist & Author · drfitznutrition.com
Educational information only. The Dr. Fitz Metabolic Longevity Protocol and any associated content are not a substitute for evaluation, diagnosis, or treatment by your physician. Consultations are online educational sessions and do not establish a doctor–patient relationship. NeuroAxis® statements have not been evaluated by the FDA and the product is not intended to diagnose, treat, cure, or prevent any disease.