Mitchell Allgood's photo once hung on the wall of a restaurant in Sydney's inner-west for setting a "schnitzel challenge" record but the St George Illawarra forward now holds the mantle as the NRL's most devout vegan.

"I wouldn't even know what meat tastes like any more," said Allgood, who established a record for diners at the Austrian Schnitzelhaus chain of restaurants in 2012 by eating 1kg of chicken schnitzel with chips and drinking a one-litre stein of beer in 14 minutes.

"If I can become a vegan anyone can."

The 29-year-old prop, who will line up for Dragons in Saturday's trial against Newcastle at WIN Stadium, became a vegan more than three years ago while playing for Hull Kingston Rovers in Super League and is influencing other players to modify their eating habits.

St George Illawarra teammates Jordan Pereira and Darren Nicholls are now dairy free, while former Dragons prop Mose Masoe turned vegan after joining Hull KR, along with Allgood's former Robins teammate Kieran Moss.

"I don't shout it from the rooftops but a few of the boys have made changes in their diet, and they are seeing the immediate health benefits and performance benefits," Allgood said.

"They are feeling a lot better and are really enjoying it."

NBA stars Kyrie Irving and DeAndre Jordan are high-profile vegan athletes, alongside NFL quarterbacks Tom Brady and Colin Kaepernick, while Argentina teammates Lionel Messi and Sergio Aguero are vegan during their soccer season.

Australian cricketers Peter Siddle and Adam Zampa are other sport stars to have spruiked the benefits of a plant-based diet, along with Indian batsman Virat Kohli.

Allgood said he and his wife Madeleine had decided to turn vegan in 2015 for ethical reasons, but believes being a vegan had also given him greater stamina and energy.

"The ethical side is what drives it because if it was just a diet then, like most diets, you would slip up from time to time," Allgood said.

"All the health benefits that come from eating plant-based food has made it even easier to maintain. I have found that it has increased my stamina and I can play longer minutes.

"I've had a few injuries so I wasn't training as much but through my diet I found I was able to maintain my fitness or energy levels to be able to go out and play longer minutes. That was just purely to do with what I was putting in my body.

"There is a misconception that you need to eat meat to gain protein but there is so much protein in other foods and it is easy to source at the supermarket or shops these days and you can always find vegan options at cafes and restaurants."

The former Parramatta prop's regular diet includes breakfasts comprising of cereals and fruit, vegan patties and salad or pastas for lunch, and dinners such as falafel, pies, vegetarian lasagne and bean burritos.

St George Illawarra players are given lunch at training and the club now offers vegan and dairy-free options such as beetroot, bean and quinoa patties with salad. Allgood adds protein powder to smoothies and makes his own protein shakes at training.

The night before playing, he usually eats spaghetti bolognese made with plant-based mince.

"I have never been more conscious of what I am getting out of each meal than I have since making the change to be vegan," Allgood said.

"I used to just eat whatever and never really think about whether I was having a balanced diet. I would predominantly eat meat. I wasn't someone who ate lots of salads and vegetables. My diet now is pretty much the same as what everyone eats, except it's an alternative to eating animals.

"Everyone at this club has just been accepting, nothing is ever a hassle. The players ask lots of questions but it is more out of curiosity. They are not offended by my decision, it is just what I do."

Allgood said his main motivation for becoming vegan had been animal welfare, along with environmental impact and health benefits.

"I just had a shift in the way I saw things," he said.

"I never really questioned what I ate. It was just what we did and immediately I realised that I didn't want to be eating animals.

"I don't think that we are meant to be eating animals. I feel like our bodies are designed to be eating predominantly plant-based and fruits and vegetables and things that we can get naturally without having to source it from eating another life.

"For me it's animal welfare first and the moral understanding that we should be doing that and then the environmental impact. All the health benefits are just a bonus that come with that."