In the NFL, former lineman David Carter was one of the first to go vegan in 2014 while he was still playing. Now, he's an advocate for plant-based diets, going by the nickname, The 300 lb. Vegan. Carter, 30, says the reason for his switch in diet stemmed from health concerns.
"I was young, 22, 23, dealing with old-man illnesses at a really young age," Carter tells CNBC Make It. "I was playing a professional sport where you're supposed to be touted as one of the strongest guys, the world's top athletes and all this, but [I was] taking high blood pressure medication...painkillers, anti-inflammatories....a long list."
Carter was also struggling with painful tendinitis.
"It was hard for me to do bench press, it was hard for me to do push-ups," Carter says. "Even lifting my body out of the bathtub, it felt like someone was taking a knife to my elbows and twisting that knife around and it was excruciating pain."
The athlete was inspired to switch his diet after seeing the documentary, "Forks Over Knives," which "examines the profound claim that most, if not all, of the degenerative diseases that afflict us can be controlled or even reversed, by rejecting animal-based and processed-foods," according to its website.
"I was drinking a milkshake while I was watching the documentary and poured it out," Carter tells SI.com.
The film touched on the idea that body inflammation is linked to the consumption of animal products, and Carter says it "completely changed" how he thought about eating.
But even if you're not an athlete or dealing with disease, Carter says going vegan can help with "just overall discomfort from eating unhealthy foods and the effect that has on your body," he says. "[I]t's just a lot easier for you to function during work because your body is functioning better."