Keto Diet Experiment Part 1: 45-Day Fasted Cardio Results

A 45-day keto and fasted cardio experiment examining visceral fat loss, strength retention, metabolic clarity, and the effects of disciplined refeeding.
Mario McKenzie before and after photos showing 45-day keto diet experiment transformation results with visible fat loss

For years, I’ve treated my body like an urban laboratory—a place for calculated experiments to unlock what this biological machine is truly capable of. Each self-experiment follows the same framework: change one variable, observe, adjust, repeat.

My latest test had a specific target. On Day 0, I wrote a simple hypothesis in my notes: If I combine strict keto with extended daily fasts, maintain fasted morning workouts, and hit 10K steps daily, I can strip visceral fat fast without losing strength or muscle mass. Switching my focus from power to aesthetics.

Then I pressed start.

Days 1–14: The Switch

The first two weeks felt like a complete system reboot. I compressed my eating into a tight 5-hour window—usually one substantial meal, sometimes two smaller ones—built around eggs, beef, chicken, salmon, avocado, and greens. The goal was simple: establish a rhythmic routine that would drive results while making the process sustainable.

My mornings became ritualistic. Two sharp shots of a ginger-lime-lemon-garlic tonic I brewed like lab stock, followed by lemon water with a pinch of salt, then black coffee for an energy boost. At 5:30 am sharp, I hit the gym for 30 minutes of fasted incline walking—level 18, speed 2.5 to 3.0—pushing hard enough to feel the work bite.

Mario McKenzie keto experiment morning setup showing scale, protein powder, creatine, workout shoes, gym gear, and magnesium supplements.
The daily arsenal: Every morning started with the same systematic preparation—scale for tracking, supplements for performance, gear for the fasted workout ahead.

My body fought back in predictable ways. Dry mouth, restless sleep, mild constipation, and energy that swung wildly before my daily refeed. The adaptation felt messy and uncertain. But somewhere around day 10, something shifted. The mental fog that had been coming and going simply… stopped.

By week two, the transformation was undeniable. The constant hunger signals that had driven my normal eating patterns vanished completely. My thoughts sharpened. Most remarkably, after breaking my fast each day, my energy spiked cleanly—no crash, no afternoon energy crater. Eliminating that familiar midday fatigue became one of the biggest wins of these early days.

Days 15–30: Signal > Noise

The routine crystallized into something powerful. Steps climbed effortlessly (many days 15,000+), lifts held steady, and I finally stopped mistaking boredom for hunger. This was what “signal over noise” actually meant: meals had one job—deliver protein and fat, eliminate carbs, get me back to work. When cravings knocked, I had my arsenal ready: cheese sticks, hard-boiled eggs, 100% cocoa, or a spoonful of something fatty. The morning and evening ginger tonic shots stayed in rotation, their spicy bite oddly satisfying and effective against both cravings and bloating.

The physical wins came fast and unexpected. Strength didn’t just hold—it spiked. I hit fasted PRs, including a 105-lb incline dumbbell press and 115-lb flat bench while the scale inched steadily downward. My dandruff and dry scalp vanished like they’d never existed. The mirror confirmed what the scale suggested: real changes around my waist and thighs. Looser belt and clothing became daily reminders of progress.

Mario McKenzie day 20 progress photo showing early keto diet experiment results and body composition changes
Day 20 checkpoint: Early signs of the protocol working, though the most dramatic changes were still to come.

But clarity came with a cost. As the weeks progressed, I noticed the edges of my mood growing sharper. Small frustrations lingered longer. The steady mental state I’d gained felt increasingly flat—not depressed, but missing the peaks that carbs and sugars had provided. My nervous system seemed to be running on a different frequency, one that was efficient but emotionally muted.

Time for another variable test. I implemented what I called a “strategic refeed”—yogurt with cottage cheese drizzled with honey. The first few bites delivered an incredible rush, my taste buds hitting a familiar nirvana I’d forgotten existed. However, instead of spiraling, I executed a clean bounce-back protocol: 18-24 hour fast, 1 hour fasted incline walk, aggressive electrolytes, then straight back to the playbook. Ketosis returned quickly. The variable was controlled.

Days 31–45: Refinement

By week five, my days ran like clockwork—and I loved it. Fast from 5 PM to noon the next day. Morning incline walk followed by light movement throughout the day, easily clearing 20,000+ steps. Lift. One substantial meal anchored by eggs, beef or chicken, salmon, avocado, and greens. Butter without apology. Creatine, magnesium, potassium, and constant hydration with lemon and salt. The system had become effortless.

Then something remarkable happened. During this period, I began experiencing what I can only describe as a euphoric wave that rolled through my entire body after the first few bites of each meal. Not a sugar rush—there was no sugar involved—but something deeper. It felt like my nervous system was flipping a master switch from fight-or-flight straight into rest-and-digest mode with commanding authority, sending a toe-curling sensation throughout my body. The sensation was so intense and unexpected that I started taking special notes of the feeling.

I learned to work with and enjoy this phenomenon rather than question it. Eat slowly, breathe deeply, let the response happen. The post-meal rush became a daily highlight I looked forward to, not some weird side effect to endure. My mood stayed flatter than before, but it felt more like operating on a focused frequency—steady, clear, unshakeable. Even food became utilitarian unless it was perfectly fresh, which turned out to be useful. When pleasure stops driving decisions, discipline becomes easier to measure.

The final results spoke clearly. Digestion simplified dramatically—fewer bathroom trips, zero bloating. My muscles looked slightly flatter from depleted glycogen, but definition sharpened in ways I hadn’t expected. Strength held completely. At Day 45, the scale read 213 pounds—19 pounds down from my 232 baseline—with the visual changes hitting exactly where I’d targeted: midsection and love handles. My thighs and glutes shrank somewhat, but those were acceptable trade-offs for the results I was after.

Mario McKenzie 45-day keto experiment final results showing detailed midsection fat loss and improved muscle definition
The target achieved: 45 days of disciplined execution delivered exactly the midsection results I’d hypothesized—visceral fat gone, definition emerging.

What I Learned

Forty-five days taught me things I hadn’t expected to learn. The combination of fasted cardio and strict keto didn’t just work—it systematically targeted visceral fat with surgical precision. But the real revelation wasn’t about fat loss protocols or workout timing. It was about the profound neurological response I’d stumbled into.

That euphoric wave after breaking my fast each day wasn’t just pleasant—it was my nervous system announcing a complete metabolic shift. I’d accidentally discovered what deep refeeding feels like when your body is truly primed for it. The intensity was so consistent and powerful that it became a daily landmark, a biological confirmation that the experiment was working on levels I hadn’t anticipated measuring.

Equally surprising was how monotony became an ally. When food stopped being entertainment and started being pure fuel, intention took the wheel completely. The strategic refeed taught me that planned deviations don’t derail systems—they test and strengthen them. Electrolytes and creatine went from supplements to essential infrastructure, stabilizing not just my performance but my entire mood baseline.

Crossing the Halfway Mark

At Day 45, I stood 19 pounds lighter, visibly leaner, and mentally sharper than when I’d started. The abs weren’t fully carved yet, but the trajectory was undeniable. My hypothesis had been proven sound: aggressive fat loss without strength or muscle mass sacrifice wasn’t just possible—it was repeatable and sustainable.

More importantly, I’d refined my understanding of what my body could handle and how it responded to extreme but calculated stress. The first 45 days had been about proving the system worked. The next 45 would be about discovering how far I could push it.

The second half would demand a different kind of precision—carving definition, managing recovery, and walking the fine line between breakthrough and breakdown. I’d learned to read the signals clearly. Now it was time to see how far I could take them.

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