Fish food and ammonia take about the same amount of time. The difficulty with fish food is controlling the ammonia dosage since you are relying on the food decaying in the tank.
It is a very imprecise method but better than the 'chuck some fish in and wait for them to die then do it again' method that used to be used....
For instance, my most recent fishkeeping 'bible' (I've pretty much given up on fish books for information now; they're for recreation only now I have the internet ), published in 1991, makes no mention of cycling whatsoever; it does have half a page on the nitrogen cycle, but none at all on how to 'mature' a filter, as it was called in those days.
You wouldn't believe how mental people thought I was 'maturing' my tanks with fish food after I'd read about it in a copy of TFH!
And when I very first started fishkeeping we didn't have test kits or dechlorinators or anything! You have no idea how lucky you (and the poor fish!) are living in these enlightened times
Yup, finished mine in december. Read the Bigineers Resource Centre carefully, its all in there, then if you have any further questions I will endevour to supply support.