For the love of food

I have a secret. I'm not very good at secrets, so I've managed to keep it for a whole week. Sort of. I mean, I told my friend McG and she told everyone we know because she's kind of like a proud mama, so I guess it's not really a secret any more. But I digress.
Anyway, here it is, for the whole internet to witness.
I'm training for a half marathon.
That does not necessarily mean I am going to ACTUALLY RUN a half marathon. That is Crazy Talk. I am however following a training plan (the Hal Higdon Novice plan) at the end of which I will suppooooossedly be able to run 13.1 miles straight. We'll see about that. I mean, the last day of the plan does just happen to coincide with the Manchester City Marathon & Half Marathon, and I do happen to be a stone's throw away from good ol' ManchVegas. But that's just a coincidence.

Anyway, the point of this is that in order to step up my running and general fitness level, I have to step up my eating habits as well and I just don't know how to do that. I've noticed that since I started running more, I have been absolutely RAVENOUS. I don't generally have a huge appetite (especially in the summer), and I use most of that appetite eating tasty things that aren't good for me, so this newfound hungryness is kind of hard to deal with.
Yesterday was my "long run" day, and I ate a bag of butter lovers popcorn and half a pan of brownies for my after-dinner snack.
Now, I'm not sure if this is related, but this morning when I got to work and started sucking down my iced coffee as per usual, I started to feel so incredibly ill I almost didn't make it through the day. After a lunch of Pepto and saltines (reason #467 to love self-checkout) I started feeling better, but I still had to come home and take a nap.
I need sustenance. I need healthy sustenance and enough of it that I don't run out of all the healthy stuff in the house and start digging into the sour patch kids at 4pm on any given weekday. That is not going to make me feel good. At all. I'm starting to think that frankly, I can't eat vast amounts of candy any more or my blood sugar level is going to plummet, leaving my gasping for breath and dragging my feet halfway through a four mile run. And that will just not do.
I'm also wondering if I should try and give up caffeine. Just for a bit. The thought of that turns my blood to ice, but I can probably do it for a whole week. Next week. Or maybe the week after.
Also beer. But only crap beer, which I shouldn't be drinking anyway, because it is gross and I hate it. I refuse to give up Guinness. Guinness is good for me.
This should be interesting.