For whatever reason, it's been a long time since I've gotten a full night's sleep without waking up at least once or twice during the night. Sometimes I'm able to just go back to sleep, other times I will lie awake in bed for an hour or so while my mind chases its tail and I patiently wait to be tired enough to return to slumber.
This morning, I woke up at 4:38, wondering if the xenomorphs from the Alien franchise actually eat people.
I know, Canadians are supposed to be worrying about Donald J. Trump's tariffs and his threats to annex our country, but the heart knows what it wants, so here we are.

On first examination, the answer is no. Logic says that the Alien fetus should eat the host, as with digger wasps, which would provide them with the biomass that they need
for the growth spurts that we see in all the movies, but that doesn’t
seem to be the case. Instead, chestburster host corpses (or soon to be corpses) are a standard element of Alien nest decor, held captive in the structure of the walls until the fetal Alien emerges, then left in place rather than consumed.
But why not eat them? The mimetic nature of the Alien DNA (or equivalent thereof) which apparently enables them to use any species as a host, would suggest that they would also be able to metabolize virtually anything, and as such, well, seems an awful waste, to quote Sweeney Todd's Mrs. Lovett.
This all leads to a bigger question: what DO the damn things eat? In the second film, there's apparently a thriving Alien hive on LV-426, but there are only 158 colonists - even if the Aliens were eating them, that hardly seems like an adequate ongoing food supply, and the planet itself seems to have a limited biosphere for hunting and gathering. Admittedly, LV-426 isn't really the ideal environment, if the ship carrying the eggs hadn't crashed there, there wouldn't have been an Alien hive*. It may well be that it really wasn't necessary to nuke the site from orbit, but rather to just let the hive starve itself to death - or at least to stop providing it with new hosts in the form of colonial marines.

Actually, when you think about it, the whole Alien reproductive cycle seems to be oddly restrictive. It's all well and good to have the queen constantly producing all those eggs, but if the process is dependent on face huggers having hosts to impregnate*, the warriors must need to be constantly on the hunt for suitable subjects. It also posits that they evolved in an environment with an adequate supply of said hosts*, which, based on the nature of the facehuggers, must have something resembling the human head and digestive system.*
So, short answer: apparently no, but really, they should. And back to peaceful sleep...
- Sid
* This leads to the question of what the xenomorph homeworld ecology would look like, if there is such a thing, as opposed to the alternative theory that the Aliens are actually an engineered bioweapon.
P.S. Recommended reading for this discussion would be Aliens: Labyrinth, the 1993 Dark Horse Comics miniseries written by Jim Woodring and disturbingly illustrated by artist Kilian Plunkett.
As part of its unsettling narrative, the story shows its villain, Dr. Paul Church, living in an alien hive for an extended period of time, during which he becomes an unwilling expert in the xenomorph life cycle. (It also drives him insane, but that’s neither here nor there for the purposes of this debate.)
The story adds quite a bit of horrifying depth to the ecosystem of the Alien hive: pools of digestive liquid that create a sort of biological slurry made up of dissolved victims; which is then fed to captives who have been crippled but kept alive; the possibility of being an Alien slave worker, rather like some kinds of ants, and so on. It's fascinating stuff, but I can't speak to the canonicity of the original Dark Horse material.