system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What makes the impossible burger taste like meat? Is it healthier to eat vegetables that have been manufactured to taste like meat?
gpt
What Impossible Foods did that was clever is they experimented on which elements of beef gave it the flavor we associate with hamburger, and they sought out plants that had the same or similar elements.  So they figured out things like heme (part of hemoglobin, and what gives blood its red color) is very common in animal muscle, and contributes to it's taste, but it is also found in certain bean plants (beans have long been used as a meat substitute).  By identify multiple different elements such as this they built had the building block flavors to emulate meat without needing meat.  They also worked very hard on their texture, to make it's mouth feel as similar to a burger patty as possible.  All this research has lead to a plant based foodstuff that is fairly close to a beef patty.

An impossible burger isn't going to be meat eating celery for lunch.  It still has a decent amount of fat and calories in it.  It's more like a turkey burger than anything else.  Healthier, but not healthy exactly.  But it does allow people with religious, ethical, and some dietary restrictions on eating meat to enjoy something pretty close to the real thing.