Cannibal

Cannibal is a Fallout 3 Perk.
 * Requirements: Level 12
 * Ranks: 1
 * Benefit: With the Cannibal perk, when you’re in Sneak mode, you gain the option to eat a corpse to regain Health. But every time you feed, you lose Karma, and if the act is witnessed, it is considered a crime against nature.

Other Effects (Possible Spoilers).

Allows for expanded dialogue options when speaking with The Family in the Blood Ties quest and when speaking with the cannibals in Andale.

Can someone check...

10 - 12% health, depending on your medicine level.