I believe the story appeared in Isaac Asimov's sience fiction magazine, but may have been in Fantasy and Science fiction.
Humans are in a war with an unseen, brutal alien race called "shards".
The story is told from the viewpoint of a suicide soldier sent to a planet colony where people refused to evacuate, as the shards butcher people alive and hook their central nervous systems up to their ships' computers/AI.
These suicide soldies have a "glucose pump" which was taken from a captured shard ship.
I would love to know title and author of this piece.