Cook employed the help of Dr. Garth Davis to get his diet back on track. Davis, a plant-based advocate, encouraged him to give up processed foods and include whole, natural vegetarian alternatives into his regimen after undergoing gastric bypass surgery. Next, Cook surrounded himself with a team of people to help him live a consistently more active lifestyle. For the first time in his life, he set long-term health goals and was dropping weight—fast.
"All the hard work I put in was worth it, and it made me know that someone who that had been following my journey for inspiration would see that anything is possible."
"One of my team members, Will Castle, told me I needed to have a goal of something that I couldn't do with a year's worth of work. Basically I needed to work towards a goal for a long time," Cook says. "I chose a triathlon because the endurance of an IRONMAN was something that always amazed me. Starting off I did super sprint triathlons then upgraded to sprint triathlons and so on. My doctor asked how I was losing weight so fast, and that's when he revealed that he was an IRONMAN."
Cooks' first triathlon was the Jeff and Brede's in Houston. He worked out in the pool, bought a bike and started doing small brick workouts. As a child he always wanted to complete a marathon, so he naturally gravitated to the running leg; the performance and science behind the bike leg was also something he found especially interesting. Cook was hooked after crossing the finish line for the first time and immediately setting his sights on completing his first IRONMAN.
"Although I was happy, I immediately thought of what I could do next after every time I crossed the finish line," Cook says. "When I finished the Miami race, I came across the line knowing I was going to do IRONMAN Texas in 2017—six months from that date I would be an IRONMAN, approximately a year and a half since I was close to 500 pounds."
Hearing Mike Reilly say, "You are an IRONMAN!" is something all triathletes look forward to, but for Cook the four words held an extra special meaning given his background.
"It just solidified the fact that all the hard work I put in was worth it, and it made me know that someone who that had been following my journey for inspiration would see that anything is possible," Cook says.
After defying the odds by losing over half his bodyweight and completing one of the toughest one-day endurance events on the plant, what's next?
The IRONMAN World Championship, of course.
"I have received a spot for the IRONMAN World Championship because I raised $100,000 for charity," Cook says. "Currently I'm traveling the United States doing six 70.3s, and I've also been asked to be a My Time to Tri ambassador. It's an initiative to bring 100,000 people into the sport, and I'm honored to have a role in that. There's probably an extreme triathlon in my future. I also see myself doing a 100-mile run or some equivalent."
Not surprisingly, Cook's physical and mental transformation has inspired people in a similar situation to make big changes in their lives. Cook advises keeping it simple—start small and work your way towards a larger goal.
"Realize you need to change, set a goal for something you can't do currently, get a team of people who want to help you and train, train, train," Cook says. "Reach the goal. Move the goal. Repeat."
It's a mantra all aspiring athletes can heed, no matter your weight or background. One thing's for sure, Cook has embodied the IRONMAN spirit ever since that fateful day in Dallio's office.
"All I can tell you is I changed my health, and my whole family has changed right along with me," Cook says. "My marriage got better, my work ethic got better, my world view has changed, my hobbies have changed—everything has become better in my life."
Learn more about Marcus Cook, and follow his weight-loss and triathlon journey here. Be sure to follow Marcus Cook at the 2018 IRONMAN World Championship in Kailua-Kona, Hawaii, on Oct. 13.
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