They look like meat. They cook like meat. And according to a lot of people who’ve tried them, a new generation of meat substitutes taste like meat.

A number of popular restaurants are now adding these products to their menus.

Just last week, McDonald's announced plans to test a "P-L-T", a plant, lettuce, and tomato burger at one of their stores in Canada.

>> Read more trending news

This follows the introduction of the “Impossible Whopper” at Burger King and Dunkin's roll out a new breakfast sandwich that features a vegetarian sausage.

Siva Kumar has been offering an Impossible Burger at the Walnut Grille in Newton, Massachusetts, for several months now and he says sales are sizzling. "People really, really like it. It literally tastes like meat. It is very juicy."

The Impossible Whopper is made with a meat substitute created by Impossible Foods. McDonald’s and Dunkin' are featuring products created by Beyond Meat. Both companies have developed elaborate procedures to extract protein from plant-based sources.

One of the selling points has been a positive impact on the environment. Raising cattle generates greenhouse gases and the clearing of wooded areas.

We asked Marisa Hastie, a professor who teaches classes in nutrition and exercise at Lasell University in Newton, if what might be good the planet is also good for our health.

Hastie said the Impossible Burger is a really good source of protein, but cautioned that it has more sodium than a regular beef burger and a higher amount of saturated fat - primarily from the coconut oil that's added to give it the "mouth feel and juiciness of a regular burger."

Hastie believes these products might be helpful for vegetarians who find it challenging to get enough protein. But for meat eaters, "you're probably going to be better off just going with your regular beef burger." "It's going to be a whole food. It's going to be richer in protein and better for you overall, especially with concerns to the saturated fat and sodium which we know contributes to a whole host of chronic diseases," she said.

At the Walnut Grill, Kumar thinks sales will continue to soar, noting "it's tasty. They don't miss the beef.

When it comes to calories, Consumer Reports found a burger made from 80% lean beef has 306 calories, compared to 250 in a Beyond Burger, 240 in the Impossible Burger, and 150 for a traditional veggie burger.