Famous Brands has bought a 51% stake in the mostly vegan Lexi's Healthy Eatery, it said on Wednesday, as the restaurant-owner forays into the fast-growing plant protein sector.

Demand for plant-based meal replacements has risen, with much of the demand led by millennial and young adult consumers as they become more conscious about what they eat.

The owner of hamburger fast food chain Steers and casual dining restaurants Wimpy and Mythos said the acquisition is part of its three-year strategic plan, which includes buying brands that have the potential to lead in their category.

Famous Brands' existing portfolio does not include an exclusively vegetarian or plant-based offering, "and as a forerunner in its category, Lexi's is a good fit for the group," it said.

"The trend to healthy eating and plant-based foods has been present in the market for some time, and continues to grow; this is evidenced by the increasing receptiveness to and take-up of healthier and vegetarian options on the menus of the group's existing brand portfolio," the company added.

Lexi's, whose slogan is "Eat more plants", is a casual dining restaurant brand, offering a full-service, sit-down, plant-based dining experience across four restaurants, of which one is a franchise.

It also operates a fledgling central kitchen that develops and produces meals for the restaurants and sells a limited range of convenience frozen goods to a small number of supermarkets.

The acquisition pertains to the franchise and central kitchen operations of the business, with scope to develop Lexi's products for the supermarket retail space and leverage off the group's route to market, Famous Brands said.

Founder Lexi Monzeglio said the partnership with Famous Brands will help the company to grow "the conscious market, making a plant-based, sustainable lifestyle more accessible and convenient for our communities."

As the health and wellness culture gains traction in traditionally meat-loving South Africa, on Monday, the country's biggest food producer Tiger Brands said it was co-investing in plant-based food company Herbivore Earthfoods with private equity firm Secha Capital.