Just after the discovery of warp drive, the ship Taurus crashed on Vega I, with the Humans secluded on a mountain during heavy snowfall. The captain, Derek Birkeson, met with a small band of Sleaks who were worse off than his people were, with two dead from starvation and the rest weak with hunger. Instead of helping them, Birkeson elected to kill them and used their flesh to feed his colony. He never told anyone but his first officer where the food came from.
During a dream-like illusion involving his former lover Brianna, Rudolph Ransom remembered that he read about the situation with the Sleaks. He realized that he had done something similar when he used the nucleogenic lifeforms. (VOY short story: "The Fate of Captain Ransom")