More American consumers have turned to plant-based meat substitutes since the pandemic, and now some of the biggest fast-food chains in the US – including McDonald's — will source the products with producers.

The popular plant-based meat alternative company Beyond Meat signed a new partnership with McDonald's last week, a vital step in the growing shift to take meat alternatives into the dining mainstream in the country.

The company will be the preferred supplier for a new plant-based burger dubbed the "McPlant"and work with McDonald's to develop new substitutes for pork, chicken and egg. It also signed a new contract with fast-food giant Yum Brands, which owns and operates brands like KFC, Pizza Hut and Taco Bell, to supply new plan-based protein items as substitute options.

"We're excited about the long-term potential plant-based protein menu items have to attract more customers to our brands, especially younger consumers," Chris Turner, Yum Brands CFO said in a company announcement last week. He said that the partnership with the plant-based meat producer is driven by consumer demand for more diverse protein options.

"These deals are enormous," Ethan Brown, Beyond Meat's chief executive and founder, told CNBC. "They are the biggest deals you could possibly put together in food in our sector."

Demand for plant-based meat alternatives grew rapidly worldwide in 2020. The global meat substitutes sector is worth $20.7 billion and is set to grow to $23.2 billion by 2024, market research company Euromonitor told CNBC. That growth is being driven by concerns ranging from animal welfare to food security and the COVID-19 pandemic.

Sales of plant-based foods in the US increased by 90 percent during the height of pandemic-buying in mid-March, compared with last year's sales during that time. Sales of plant-based meat spiked by 148 percent, according to a report released last year by a market research company SPINS.

About one-third of consumers said their consumption of various meat alternatives has increased over the past year, according to a survey conducted in January by market research company Datassential.

The figures are similar for those who say they plan to increase their consumption of plant-based meat alternatives in the coming year, according to a report released in February by business news publisher SmartBrief.

Beyond Meat, founded in 2009, processes yellow pea protein, canola oil, potato starch and other ingredients to produce patties and sausages meant to mimic the taste, appearance and feel of traditional meat.

White Castle was the first quick-serve hamburger chain to partner with Impossible Foods, another meat-alternative front-runner, and it rolled out its plant-based sliders nationwide in 2018. As of January 2020, Burger King, Dunkin' Donuts, Wendy's and Carl's Jr all began deploying new plant-based menu items.

Brazil-based company JBS, the world's biggest meat supplier, announced in February that it will likely set up a new global company focused solely on plant-based products.

However, the meat alternative industry still has hurdles to overcome in different parts of the world.

The plant-based meat market in Asia may be limited by established perception issues because vegetarian meat was previously primarily eaten by followers of Buddhism in China, Elaine Siu, managing director of The Good Food Institute Asia Pacific, told CNBC.

Cattle farmers also stand in the way of the growth of the plant-based dairy market. The US Cattlemen's Association in 2018 filed a petition requesting an official definition of the words "beef" and "meat", to keep plant-based proteins out of the description.

European Union lawmakers rejected such proposals in October and allowed restaurants and shops to label plant-based products with words such as "sausage" or "burger".