Below is a very interesting post from BBC.com about what to eat after an asteroid impact. (click on image below).
When you think about it, Do you recall ever coming across a scenario of an asteroid in any survival guide? So the next best thing would be to grab your SciFi novels that do. Some of these I have read, others look intriguing for survival. If you have a favorite, let me know so I can update this list.
Seveneves by Neal Stephenson
The Left Hand Of Darkness by Ursula K. Le Guin
The Martian by Andy Weir
Shipwreck by Charles Logan
The Moon Is Hell by John W. Campbell