With plant-based meats and cheeses now a staple in most supermarkets, and 2018 even dubbed by some as 'the year of the vegan', vegan diets are becoming increasingly mainstream.

This month more than 190,000 people around the world have registered to take part in Veganuary, a movement started by a UK non-profit organisation that encourages people to ditch animal products from their plates for 31 days.

Participation has more than doubled each year since the first campaign in 2014, with one person currently signing up to the 2019 challenge every 3.5 seconds.

The goal, according to the organisation, is to inspire more people to try veganism — what it describes as "one of the most effective choices a person can make to reduce the suffering of animals, help the planet and improve personal health".

Not all researchers believe cutting out animal products entirely is necessary to improve environmental or health outcomes, but a major study last year found even well-managed meat production had a greater environmental impact than vegetable crops that produced equivalent amounts of protein.

So what has driven people to sign up to this year's Veganuary? The ABC spoke to three first-time participants to find out.

Meeting the meat

For Carly Lawless, a 24-year-old nurse living in Melbourne, the decision was largely based on ethical reasons.

Veganism had been on her radar for some time but she had previously considered the lifestyle change too drastic.

"Being in Melbourne, I had a lot of friends who were vegan," she said.

Carly Lawless is taking part in Veganuary for ethical reasons. ( Supplied: Carly Lawless )

"I had eaten vegan food before and I loved it but I always thought it would be too difficult to do on my own."

Coming face-to-face with farm animals destined for slaughter last year changed her mind.

"I went home to Darwin and my parents were housesitting on a rural property," she said.

We saw all the little pigs and then next minute I found out that my dad was actually helping his mate prepare them for Christmas lunch.

"I think that's what contributed mainly to my choice."

Ms Lawless anticipated social pressure would the biggest challenge she would face sticking to the diet this month, with her decision drawing negative responses from some.

"I've told a few friends and they're like, 'Don't go vegan, we'll disown you'," she said.

"And if you do go to a restaurant, you have a limited choice being the odd one out."

Despite this, she hoped to stay vegan after January.

"I really want to try to make this something for the long term," Ms Lawless said.

Coming face-to-face with pigs destined for slaughter convinced Carly Lawless to try a vegan diet. ( ABC Rural: Clint Jasper )

Searching for healthier choices

Yarrabilba's Joshua Peell surprised everyone, especially his vegan fiance, when he signed up for the challenge.

Tucking into a steak or 'schnitty' with his workmates after a long day had been a regular occurrence in the 21-year-old machinery operator's life.

"It's the environment I work in. The boys like to go to the pub, go grab a steak and a couple of beers," he said.

Mr Peell, who lives with high blood pressure and cholesterol, hoped making the switch to a vegan diet could improve his health.

"I've been thinking about it since August last year," he said.

"My fiance has chronic asthma and it's helped [her] quite a bit, having the healthier food rather than a lot of the processed meat.

"Just seeing the health benefits from it … that's something that I'm trying to be more conscious about."

Joshua Peell, 21, wants to see if a vegan diet improves his high blood pressure and cholesterol. ( Supplied: Joshua Peell )

He was looking forward to trying his hand at some new recipes.

"We made this really nice cauliflower bake today. I'll probably make that a couple of times this month," he said.

"I like to get a bit 'cheffy' with it so probably [there'll be] a lot of things with tofu, different kinds of stir-fries, maybe some portobello mushrooms with some bell peppers."

His fiance Christy-Lee Cole said she was excited to support him through the change, whether short or long-term.

"I was quite shocked. I didn't expect that from him," she said.

The 20-year-old nurse has already been vegan for one year; her love of animals inspired her to leave them off her plate.

"I thought, 'If I wouldn't treat my dog this way … why do I pay for someone else to do this to another animal?'" she said.

It's not just salads on the menu — even these cupcakes are vegan. ( Supplied: Anastasia Martini )

Concern for the planet

Brisbane student Jessica Davis signed up as a way to recommit to veganism, after starting a vegan diet last year.

"I have been attempting to be vegan for the last two months now but I'm not really consciously deciding what I'm [buying]," she said.

"I want to be actually committed to this instead of slipping up all the time. It just seemed like the perfect opportunity to do it."

The 23-year-old's move towards a vegan lifestyle was driven mainly by environmental concerns, with ethics and health reasons also factoring in.

Jessica Davis believes a vegan diet is the best one for the environment. ( Supplied: Jessica Davis )

"I had been considering it for quite a while," she said.

"I watched a few health documentaries but the last thing was just realising … how much of an impact an individual could make on the environmental problems."

A study led by University of Oxford researcher Joseph Poore last year estimated a hypothetical vegan world would produce 49 per cent less food-based greenhouse gas emissions, while using 19 per cent less water to meet food-energy demands, and reducing land use by 3.1 billion hectares.

Ms Davis was planning to balance her diet with "a lot of salads and probably a lot of vegan junk food that's easy to buy at the supermarket".

"A big thing with Veganuary was that they were sending out emails with meal options, so I'm hoping that I'll get a lot of inspiration from that too," she said.

"It is definitely a long-term change. I don't want to go back to eating animal products."

What's the health verdict?

Dietitians Association of Australia spokesperson and accredited practising dietitian, Themis Chrisidis, said people taking part in Veganuary — or making a long-term switch to a vegan diet — needed to pay special attention to getting nutrients like iron, vitamin B12 and calcium.

"Any diet can be safe as long as it is considered," he said.

"There are a range of nutrients that your diet will be low in as a result of restricting all food products that come from animals.

"If we don't consume foods that are either fortified with these or supplements that will help us meet our nutrient needs … then a vegan diet could be detrimental to your health.

"I'm not saying that you shouldn't do it, but I'm definitely suggesting that you should absolutely consider the nutrients that it won't have and find ways to get them into your diet."

Plant-based variations of meats and cheeses are now available in most supermarkets. ( ABC Rural: Sally Bryant )

While most nutrients could be found in plant-based sources — calcium, for example, is found in nuts, seeds and green leafy vegetables — Mr Chrisidis said a supplement would be necessary for vegans who were not consuming B12-fortified foods.

"It's about understanding how your whole diet interacts and what you might be high or low in naturally too," he said.

"A vegan diet can be quite beneficial and healthy for a number of people.

"Primarily it's encouraging us to eat more kinds of fruit and vegetables, which is a really positive thing, considering that 50 per cent of Australians don't eat enough fruit and 93 per cent of Australian adults don't eat enough vegetables.

"It also helps us reduce our intake of saturated fat — which increases our cholesterol levels — because that's primarily found in animal-based foods."

But Mr Chrisidis said that did not mean cutting animal products out completely was the only way to reap these health benefits.

Dietitians advocate a balanced and "considered" diet. ( Supplied: Sarah Oxenham )

"At the end of the day, I would probably much prefer to see everyday Australians eat more fruits and vegetables every day of the year … rather than engaging in a vegan diet for 31 days," he said.

"My biggest advice would be to please make sure you chat to a doctor and to a dietitian who understands your health status.

"If you are going to take part in any kind of vegan diet, just make sure you do it in a considered, healthy and balanced way and try to think about … how can I make this part of a sustainable lifestyle?"