Meatless burgers just got the ultimate seal of approval from the fast-food industry. McDonalds, the worlds biggest burger chain, has started selling plant-based patties at a number of outlets in Canada, with restaurants in America expected to follow next year .

Its competitor Burger King, along with a handful of other fast-food outlets, has already launched a $5 meat-free burger in some of its U.S. stores. You might still need to request that your meatless patty is cooked on a separate grill (Burger King is currently being sued by a customer who claims his plant-based burger was contaminated by meat products), but its a start.

Until recently, vegan or vegetarian options in the major fast-food chains were limited. Meat dominated the menu.

Thats changing fast. People are increasingly seeking out non-meat options, often out of concern for the environmental impact of what they eat, and companies are racing to capitalize on this.

From meatless meat startups like Impossible Foods and Beyond Meat to the worlds biggest food business Nestl, companies are producing food that looks, and often tastes, just like meat and that tends to be marketed to meat-eaters. Even big meat companies, such as Tyson and Cargill , are rushing to invest.

Meatless companies are touting their plant-based products as a planet-saving solution that will enable us to eat as many burgers as we want. (And they provide something of a retort to the right-wing claims that Green New Deal-supporting Democrats want to take away your hamburgers .) But how do their claims stack up?