A Gold Coast bodybuilder is out to prove that you do not need to eat meat to build muscle.

Crissi Carvalho became a vegan in 2011 following a health scare and returned to bodybuilding in 2014 - almost 20 years since she first competed.

In the past two years she has competed in and claimed numerous titles, including the IFBB Bikini Masters 35+ earlier this year.

Ms Carvalho (centre) won the IFBB Bikini Masters 35+ challenge earlier this year. ( Supplied: Crissi Carvalho )

She credits her diet as the key to her success.

"By doing this I found that I felt healthier, more energetic and I stopped suffering a lot of things like migraines and bloating," the 42-year-old said.

"I didn't have any of the withdrawals or lack of energy that a lot of bodybuilding competitors do.

"After I proved to myself that I could achieve this at 40 I decided I wanted to tell the world."

Ms Carvalho said she was a minority in the bodybuilding world.

"In terms of bodybuilding there aren't very many vegans doing it," she said.

"But there is a small wave of change happening there."

Ms Carvalho said her goal was to inspire others.

"That's why I keep getting on stage season after season in a bikini at almost 43 now," she said.

"If I can do it at my age I think that anybody can do it."

Vegan diet makes it difficult to build muscle: nutritionist

Billy Simmonds won the INBA Mr Universe title in 2009 as a vegetarian and has since adopted a vegan diet too.

"They all want to know where I get my protein but what they don't realise is plants have protein as well," he said.

"When you look at foods like pumpkin seeds or black beans they've got equally as much protein as some of the meat products out there."

Bond University nutritionist Dr Kristen Mackenzie-Shalders said having a vegan diet while bodybuilding could make it more difficult to build muscle.

She said it could also put athletes at risk of nutrient deficiencies in the long term.

"Where someone wants to make the choice to be vegan because of their beliefs then they just need to recognise it's really challenging and get the support to do that properly."