Burger King

Burger King is rolling out the meatless Impossible Whopper in several states, providing a new fast-food option for casual vegetarians (more on that “casual" descriptor in a moment). Eventually, every Burger King will likely offer the Impossible Whopper, since the burger has sold relatively well in test markets and has elevated the Burger King brand.

Unlike many vegetarian burgers, the Impossible Whopper is designed to taste like real meat—and some tasters claim it achieves that lofty goal.

“I couldn’t tell the difference, and I was shocked myself,” one Burger King assistant manager told The Washington Post.

So, what’s in the Impossible Whopper?

“Mostly soy protein, potato protein, coconut oil, sunflower oil, and heme,” the Impossible Foods' Whopper website reads.

Impossible Foods has spent years developing meat substitutes. The soy protein provides a “more beeflike texture,” per The Washington Post, and methyl cellulose provides a juicier bite. The secret ingredient is the iron-rich heme, produced through a complex genetic engineering process. Heme naturally occurs in all plants and animals but is found in higher quantities in animal muscle, and the soy-derived version used in the Impossible Whopper is fairly similar to its animal-derived counterpart.

There’s another reason the Impossible Whopper tastes almost like the normal Whopper: Both burger patties are fairly thin, and much of the Whopper taste comes from the bread, mayonnaise, and other ingredients.

So, should you try the Impossible Whopper? That depends. The Impossible Whopper is cooked on the same grills as other Burger King products, so contact with meat particles might make it a no-go for strict vegetarians. However, the chain does offer a vegan version, skipping the mayonnaise and cooking the patty in a microwave, away from any potential contamination.

And if you’re hoping to switch to the Impossible Whopper for health reasons, you might be disappointed. Although the Impossible Whopper has slightly fewer calories than the original (630 instead of 660), the vegetarian-friendly version has much higher levels of carbohydrates and sodium.

"The Whopper has 980 milligrams of sodium while the Impossible Whopper has 1,240 milligrams," dietitian Jessica Stafford told KMOX in St. Louis. "The American Heart Association recommends no more than 2,300 milligrams of sodium a day, and with the Impossible Whopper, you're getting well over a thousand. So the Impossible Whopper is half your day's worth of sodium, but that's okay. You can have that, but make sure everything else you have the rest of the day is naturally low in sodium."

With all that said, the Impossible Whopper should delight vegetarian diners who are looking for a fast food option. It’s not quite magical, but by all accounts, it’s fairly tasty—and while it’s about $1 more than the regular Whopper, that’s a small price to pay for peace of mind.