About Me

Hello, and welcome to BMIWeightLossCalculator.com — I’m truly glad you’re here.
My name is Jack/Yaqui Marquez, and helping people achieve a healthier weight in the safest, most effective way has been my lifelong passion.

I bring over 40 years of experience in fitness, health, and injury prevention. My journey began in New York City, where I spent my first 10 years as a personal trainer, guiding clients from all walks of life toward their goals. It wasn’t just about losing weight — it was about helping people feel stronger, more confident, and capable in their everyday lives.

For the next 17 years, I worked as a Sports Medicine Specialist, helping athletes fine-tune their weight and conditioning so they could perform at their very best. My job wasn’t just about physical readiness; it was about keeping athletes healthy, motivated, and confident in the moments that mattered most.

In the past 13 years, I’ve had the privilege of serving with the Department of Defense, working with Marines and Sailors. My role included rehabilitating injured service members, helping them regain strength, and providing ongoing education so they could maintain their health in even the most demanding environments. I’ve been more than a trainer or specialist — I’ve been a steady source of guidance, encouragement, and accountability for the people I serve.

I know that weight loss can feel like a mountain to climb, and there’s no one-size-fits-all approach. That’s why I created this website — to share free, accurate tools and resources that empower you to take charge of your health. Whether you’re an athlete, a service member, or someone simply looking to improve your well-being, you’ll find calculators, guides, and downloadable resources here to help you on your journey — all completely free.

My approach is rooted in safety, science, and understanding — but also in human connection. I’ve seen firsthand that the best results come when you feel supported, informed, and inspired. So, take a look around, try out the calculators, and let’s work toward your goals together.

Your health is an investment in your future — and I’m here to help you every step of the way.