Fitness coach and entrepreneur Marcus Filly recently shared something most influencers won’t admit: his testosterone was catastrophically low for years.
Despite trying every trendy hack on social media, nothing worked.
But after finally abandoning the fad diets and extreme approaches, Filly managed to more than double his testosterone levels using the most unsexy method imaginable: eating more food and lifting heavy.
His journey reveals why chasing quick fixes often backfires—and why the basics, done consistently over years, actually deliver results.
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Years of Dangerously Low Testosterone
Filly’s testosterone struggles began in his 20s while competing in CrossFit. Despite being in peak physical condition, his levels never approached normal range.
Medical testing ruled out serious underlying conditions, but the mystery remained. Even after retiring from competitive CrossFit to recover from burnout and chronic injuries, his testosterone refused to budge despite continuing biannual blood work.
I’ve always had low T. So low that I haven’t even been close to the baseline of normal until now.
What makes Filly’s case particularly instructive is that he wasn’t dealing with obesity, sedentary lifestyle, or obvious health problems. He was doing everything “right” according to conventional wisdom—yet his hormones told a different story.
The Failed Experiments: Every Trendy Protocol Imaginable
Determined to find answers, Filly embarked on years of self-experimentation. His approach was methodical: change one variable at a time and stick with it for months to ensure accurate results.
The Vertical Diet Disappointment
In 2018, Filly adopted Stan Efferding’s Vertical Diet to address digestive issues. This protocol emphasizes easily digestible foods to optimize gut health and nutrient absorption.
He consumed chicken broth by the crate. His testosterone didn’t move.
Intermittent Fasting Backfired
Next came intermittent fasting, which research shows has mixed effects on testosterone depending on body composition. For overweight men, it can help indirectly by improving insulin sensitivity and reducing body fat.
But for lean men like Filly, the results can be counterproductive. He experienced the negative side of this equation firsthand.
Six Months of Carnivore: Zero Results
Perhaps most dramatically, Filly committed to a strict carnivore diet for six months. He consumed liver, organ meats, and butter with minimal carbohydrates.
Guess what? This did my testosterone zero favors, and it tanked my cholesterol markers, to boot.
The extreme dietary restriction didn’t just fail to boost testosterone—it actively harmed other health markers.
The Pandemic Pressure Cooker
When COVID-19 shut down gyms worldwide, Filly pivoted to creating low-equipment backyard workouts. The content exploded in popularity, eventually becoming Persist, his current training program.
But success came with unexpected consequences. The social media spotlight created intense pressure to maintain an extremely lean, muscular physique year-round.
Filly dropped to his lowest adult body weight ever. This proved catastrophic for his hormonal health and created a hole that would take years to climb out of.
This was terrible for my hormonal health and not a good example to set. It dug my body, my mental state, and my testosterone in a hole that’s taken years to climb out of.
Depression set in. His health deteriorated despite all his efforts, and he found himself weaker and more injury-prone in the gym.
The Turning Point: Eating More, Not Less
Recognizing something fundamental had to change, Filly first addressed his mental health—a step he emphasizes as crucial for anyone in similar situations.
Then he made a radical decision: eat substantially more food.
He increased carbohydrate intake significantly and committed to a lean bulk, despite the challenge it posed to his body image. His daily caloric intake climbed from 3,000 calories or less to an impressive 4,200 calories per day.
The transformation didn’t happen overnight. Eighteen months later, his testosterone jumped from 230 to 447—a massive improvement that confirmed he was finally on the right track.
Doubling Down on the Basics
Filly continued this approach for another year, maintaining a body weight he felt comfortable with while fueling consistently with adequate protein and carbohydrates. He abandoned restrictive diets entirely and focused on getting quality training sessions.
When his most recent blood work returned, the results were stunning: testosterone had climbed to 519—two and a half times higher than his 2022 levels.
My testosterone went from that 447 at the beginning of the year to 519 at the end of the year. That means it’s two and a half times what it was in 2022 to now.
The Unsexy Truth About Hormone Optimization
Filly’s experience challenges much of what circulates in fitness culture about testosterone optimization. His key takeaways demolish popular myths:
- Healing takes years, not months. Hormonal recovery cannot be rushed or hacked with shortcuts.
- Adequate fuel matters more than restriction. Bodies function optimally with sufficient calories matched to activity and goals, not minimal intake.
- Extreme leanness has hormonal costs. The pressure to maintain unrealistic body composition year-round damages both male and female hormone profiles.
- Fad diets aren’t necessary. Simple, unprocessed foods with plenty of protein and carbohydrates outperform trendy elimination protocols.
- Consistency beats intensity. Regular heavy lifting combined with general activity throughout the day produces better results than extreme training approaches.
Why More Food Boosts Testosterone
The mechanism behind Filly’s success isn’t mysterious. Chronic caloric restriction signals the body that resources are scarce, downregulating non-essential systems including reproductive hormones.
Adequate nutrition—particularly sufficient carbohydrates—signals safety and abundance. This allows testosterone production to normalize alongside other anabolic processes that support muscle growth and recovery.
Research consistently demonstrates that low-energy availability suppresses testosterone in both men and women, particularly among athletes maintaining very lean physiques.
Practical Application: What Actually Works
Based on Filly’s multi-year experiment on himself, the prescription for hormonal health isn’t complicated:
- Eat enough food. Match caloric intake to activity level and body composition goals rather than minimizing intake.
- Prioritize protein and carbohydrates. Both macronutrients support training, recovery, and hormone production.
- Build meals around whole foods. Simple, unprocessed ingredients form the foundation, with room for enjoyment.
- Lift heavy regularly. Resistance training several times weekly provides the stimulus for adaptation.
- Stay generally active. Movement throughout the day complements structured training.
- Give it time. Expect meaningful changes to take months or years, not weeks.
Perhaps most importantly, Filly’s journey underscores that hormonal health cannot be separated from overall wellbeing. Mental health, adequate recovery, sustainable body composition, and consistent habits all contribute to the bigger picture.
For men struggling with low testosterone despite doing “all the right things,” Filly’s experience offers a counterintuitive but evidence-based path forward: stop restricting, start fueling properly, train consistently, and exercise patience.
The answer might be boring, but boring works.
