Bellerin made the comments during a video he made for Veganuary - a charity which supports people as they try a vegan diet throughout January.
The athlete, who plays for Arsenal, went vegan in 2017 after trying a plant-based diet for three weeks. He felt so good, he decided to ditch animal products full-time.
"Being a professional footballer means your diet has to be absolutely on point," he says during the Veganuary video. I was already eating meat less and less when I started watching documentaries like What the Health.
"I realized then that there were athletes out there that were not just vegetarian, but actually vegan. So I started researching and found out that a vegan diet wasn't just suitable for me, it was actually better for my body. So I switched.
"My family's family and they eat meat with almost every meal, but I wanted to try veganism to see if it could help me achieve my full potential, and it did - really quickly."
According to Bellerin, the diet helped with inflammation and recovery between games.
Vegan for the animals
"Health is not the only reason I'm vegan," he adds. "It was the ground zero, but now there are other reasons that push me to do it.
"The sustainability of the environment and animal cruelty now motivate me just as much as health.
"The way I feel physically and mentally, knowing I'm doing the right things, makes me really happy to be a vegan."
You can watch Veganuary's video here