Gone are the days when vegans and vegetarians couldn’t order a hamburger on the menu.

Alternative meat brands such as Impossible Foods and Beyond Burger are popping up in not only sit-down restaurants and grocery stores, but also fast food joints across the country.

They call it the future of protein: the Beyond Burger uses a mix of legumes, oils, rice protein, potato starch and other vegan-friendly ingredients, whereas the Impossible Burger is made from mostly soy. Both substances are processed into a patty or sausage, or ground up into crumbles for recipes such as tacos.

According to Forbes.com, the plant-based craze is on the rise, with 95% of U.S. grocery stores selling plant-based meat products and an increasing number of restaurants adding similar options to their menus.

Wes Moralez, who owns the Brutal Poodle on South Broadway in Denver, decided to start serving the Beyond Burger in his heavy-metal-themed restaurant earlier this year. The plant-based alternative looks and tastes like beef, he said, adding that the product fits his clientele.

“Here we have a niche concept that revolves around heavy-metal punk rock,” Moralez said. “In that scene, there are a ton of vegans and vegetarians.”

But the growing popularity and limited supply of the products has presented challenges for some restaurants.

That was the case for Curtis Baca, manager of Steuben’s in Arvada.

“We would never be able to get them,” he said of the Impossible Burger. “So we couldn’t keep it on the menu.”

Instead his restaurant serves a plant-based veggie burger that is made in-house. While he doesn’t see many plant-based eaters, the customers who try the burger alternative tend to enjoy it, he said.

Reasons for jumping on the plant-based bandwagon vary, but many people do so for the health and environmental benefits.

Jerry Casados, a plant-based nutritionist from Parker, switched his diet 12 years ago after several scares with heart disease, high blood pressure and weight gain. Rather than moving forward with more medical tests, he decided to try a strict plant-based diet, combined with medication, for 30 days.

“My cholesterol dropped about 30 points,” Casados said. “My doctor said, ‘What did you do?’ I said, ‘I changed my diet,’ and that’s the last time I saw him.”

Casados, who worked in information technology, went back to school to become a nutritionist and is now off all medication. He and his wife host a yearly summit to inform others on the benefits of plant-based eating.

The approach, he said, is more holistic.

“All your vitamins and minerals are in the plants themselves,” Casados said. “It heals the body in different ways.”

When it comes to meat alternatives like the Impossible Burger, Casados is wary. The product is still processed and contains saturated fat.

Nonetheless, he said, “It’s better than eating a mega-burger.”