I'm in a Burger King in Missouri ordering two Whoppers for myself. In my defence, this is research for Foreign Correspondent.

Key points: St Louis's 59 Burger King stores are trialling the Impossible Whopper, which is made without meat

St Louis's 59 Burger King stores are trialling the Impossible Whopper, which is made without meat The maker of the plant-based patty says feeding a growing population with animal products is "extremely inefficient"

The maker of the plant-based patty says feeding a growing population with animal products is "extremely inefficient" Missouri was the first US state to pass a labelling law to regulate use of the term "meat"

This Burger King branch, in the iconic city St Louis, is the latest battleground in the "fake meat" wars in the United States.

The city's 59 Burger Kings have been nominated as the first of the chain's stores to test the newest Impossible burger. It's a burger made without meat, but which is claimed to taste like the real thing.

The woman who takes my order says they've already sold out of the plant-based alternatives twice and while I'm there, several other customers order the Impossible Whopper.

But will it really become a popular choice for Burger King clientele or merely a novelty item on the menu, like a McDonald's salad?

One woman I speak to is a vegetarian returning after being so impressed the first time, she's brought her husband with her.

I diligently sit down to test my two burgers, one meat, one made from plants.

Impossible Food, which makes the plant-based patties, wants to expand beyond the lone vegan at the barbeque. ( Foreign Correspondent )

They taste similar, and very much like meat, although the extent to which the burger patty flavour can shine through the sauces running down my wrists is debatable.

A couple in their early 20s is also here trying the two burgers. Whopper connoisseurs, the woman says she can definitely tell the difference but she still likes the Impossible version and would order it again.

The trial in Missouri has been such a success that this month Burger King is rolling them out in over 7,000 outlets across the country.

It's a springboard launching "alternative meats" into the mainstream market, and it's got the cattle industry worried.

Burger King is rolling out the Impossible Whopper in more than 7,000 outlets across the country. ( Supplied: Burger King )

Blurring the lines

Impossible Foods' patties are made thousands of kilometres west of St Louis, in San Francisco.

Here, the company is just one of a number of wannabe biotech start-ups in the neighbourhood aiming to make food that looks and tastes like meat, but is entirely vegetarian.

Founded eight years ago, Impossible Foods has raised around half a billion dollars in investment funds from investors such as Bill Gates and Hong Kong magnate Li Ka-Shing.

Like many companies in this space, Impossible Foods claims to be motivated by the desire to do good.

The only way we can feed the world's growing population, says vice-president Nick Halla, is to rely on plant-based foods.

"We're using animals right now and animals are extremely inefficient," he said.

Their goal is lofty but their business plan is hard-edged: Impossible is aiming its products beyond the lone vegan at the barbecue, squarely at committed carnivores.

Investing in research has helped Impossible unlock the secrets to meat's distinctive flavours. Beside the company's open-plan offices, white-coated scientists are hard at work in state-of-the-art laboratories trying to recreate those tastes.

White-coated scientists are hard at work to recreate the distinctive flavour of meat. ( Foreign Correspondent )

"When you put a steak on the grill, you're smelling and tasting hundreds and hundreds of different compounds that are all created as you cook," Mr Halla said.

"But when our team dug deeper, they learned there's one protein in meat, a protein called heme, that delivers all that chemistry as you cook."

The team went looking for a useable plant-based heme and after an exhaustive process, settled on sourcing heme from the roots of soybean plants.

When cooked, the heme looks like blood, appearing as red juice rising to the top of the burger.

It seems that when courting carnivores, there's no shame in making them feel like something bled for their burger.

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A hard cell

It's not just plant-based meats that are stirring things up.

A number of companies are racing to grow meat in laboratories from animal cells. With critics calling this "frankenfood", this meat could be a harder sell.

It's certainly hard, and expensive, to make.

JUST Inc is trying to crack the cell-based meat market. ( Supplied: Just Inc )

Last year, San Francisco-based company New Age Meats developed a prototype pork sausage made with cells donated by a pig named Jesse.

While Jesse survived the barbecue, the sausage cost around $290 to make.

New Age Meats is trying to rustle up more funds to help it continue its research but says it's still two or more years away from taking this sausage to market.

Across town, Josh Tetrick, CEO of food company JUST Inc, is also trying to crack the cell-based meat market.

In on-site labs, JUST's scientists are studying Wagyu beef cells but our cameras aren't allowed too close in case we reveal some trade secrets.

Upstairs in their kitchen, a chef fries me up a solitary chicken nugget, grown from the cells of a live chicken.

Almost worth its weight in gold, this single nugget cost $150 to make.

The most available and proven medium to grow cells in is foetal bovine serum (FBS). ( Foreign Correspondent )

While no chicken died in its making, a cow may have, and that's a problem for a company which promotes itself as mostly plant-based.

This strange fact comes about because to date the most available and proven medium to grow cells in is Foetal Bovine Serum (FBS), a by-product of the meat industry harvested from bovine foetuses taken from pregnant cows during slaughter.

Cell-based companies are in a race to find an alternative to FBS because it undermines their claims to be more animal friendly.

And it's costly, making it hard to compete with the price of slaughtered meat.

JUST Inc claims it has been able to create a plant-based alternative to FBS, but my nugget wasn't made with this.

While companies struggle to commercialise cell-based meat, the sales of plant-based products are rising fast, at around 10 per cent a year.

Annual sales of plant-based 'meats' in the US are still relatively small — around $1 billion — but the growth projections are startling.

Cell-based companies are in a race to find an alternative to foetal bovine serum. ( Foreign Correspondent )

A recent report by Barclays Banks suggests global sales of plant-based meat substitutes could explode by around 1,000 per cent over the next decade, potentially reaching $200 billion a year.

The cattle industry can smell the threat, and it's starting to fight back.

Farmers fight back

Across the US, battlelines are being drawn around language. What does "meat" mean? And who has the right to use it?

To protect the meat industry and perhaps the consumer, 25 US states are bringing in food-labelling laws aiming to restrict the use of the words associated with meat.

The state of Missouri is leading the charge.

Deep in Missouri's Ozark Mountains, I catch up with Bobby Simpson, head of the Missouri Cattlemen's Association, as he herds his beloved cows.

He's a fifth-generation cattle farmer and hopes his farm will stay in his family for years to come.

It's why he's fighting so hard to rein in the marketing around alternative meats.

"We're not opposed to new products … because we are a country of free enterprise," said the slow-talking cattleman.

"But we want people to know what they're buying. We want truth in advertising."

Bobby Simpson (right) believes a new law will protect the word "beef". ( ABC News )

Missouri was the first US state to pass a labelling law to regulate use of the term "meat", trying to restrict the term to mean the flesh from a slaughtered animal.

The exact reach and consequences of this law are still being debated but Mr Simpson believes the law will protect the word "beef".

"Beef is a term that the cattle people came up with … beef, it comes from a cow," he said.

Meanwhile, the alternative meat lobby, the Good Food Institute, is challenging this new law in court for breaching free speech.

"It's rank protectionism … it's something you'd expect out of North Korea, not in the United States of America," the institute's Bruce Friedrich said.

Bobby Simpson (left) hopes his farm will stay in his family for years to come. ( Foreign Correspondent: Deb Richards )

Mr Friedrich believes the Missouri law is too broad and worries you could end up in jail "for calling a veggie burger a veggie burger".

But for Mr Simpson and other cattlemen, this is not just a game of semantics.

They have watched the sale of dairy milk drop as sales of soy and almond milk rise, and they doubt this would have been as easy if the companies hadn't been able to use the term "milk".

"We want to stop that happening in the cattle industry," Mr Simpson said.

Watch High Steaks on ABC TV at 8:00pm tonight and 1:30pm Friday August 9. Also on ABC News Channel on Wednesday August 7 at 5:30am AEST, Saturday August 10 at 9.30pm and Sunday August 11 at 5:30pm, and on iview.