Beowulf, son of Ecgþeow, while Angelina Jolie’s incredibly hot visage erupted from pools of spun gold, you were busy downing KFC-sized buckets of mead, notoriously high in carbs (40 per serving).
Judging from how tired you appeared to be in the 2007 motion-capture film, perhaps you didn’t realize not only does that much fermented honey and its accompanying yeasts muck with that CGI blood sugar and your intestines, but, as a depressant, the alcohol had you knocked out or looking narcoleptic for much of the movie.
The animators couldn’t even hide the actual effects of the double whammy of adult libations and honey to your Geatlander bloodstream.
In terms of eating plans, Grendel had it going on in Heorot. His choices might have been socially awkward (he ate your friend, and that hurts to the level of goshthatsucks), but his choices were meat-based, which kept him strong and as healthy as an ogretroll can be.
In fact, save for bleeding out through his arm, he was pretty well unstoppable. You, on the other hand, had to get naked to feel the effects of the cold air to get your blood pumping again during the fight sequence.
Not that we minded, come to think of it…