Advice required from Marathon Training Expert

A bit of a hypothetical question really, but I'll give it a go anyway........

I'm currently marathon training for Paris in 2 and a bit weeks time.  If I'm entirely honest with myself, I haven't trained hard enough, nor done all of the LSR's and I'm back to my usual feeling a couple of weeks worrying about whether I'll get around!  Although I have run 2 marathons before, they were way too long ago, before I even became a pest on this forum......

So, my question is about hitting the wall.  My last couple of LSR's have been cold, windy days, I have eaten rubbish in the days leading up to it (I'm good at that), I only drink water after every lap (about 7 miles) and there are no crowds to cheer me on or adrenaline of the big day to see me through.

So, on the basis that I seem to hit around 18 miles and can't go any further, on the big day with eating well prior, crowds, adrenaline, fuelling stations etc at what point do you think I will reach this stage?  I am hoping to last as long as possible so I only have a few miles to grind out, but am worried that if I crash and burn at 18, I'm gonna be screwed and it may be a long walk!

Honest opinions, or guesses would be nice!  (If it helps, I've ran 18 miles twice, 17 twice and done a 16.3 mile race, but have ran no further than 18 miles).  Let's just say my schedule other than that has been patchy, perhaps 3/4 runs per week.

Bwhahaha.. you slacker Coops!

Most important thing, really make sure you're properly hydrated in the lead up to the marathon; also boost your glycogen stores in that period also..

Anyway, I'm off to watch Top Gear -------->

I am a slacker.  I always start with good intentions, but then nighs out, takeaways, weekends away etc all get in the way. And I know what I'd rather be doing!!

IMO, taper + sensible carb loading strategy + sensible pace on the day...  is getting you 90% of the way towards avoiding the wall.  Yes, eat a good breakfast and sort out your race fuel / hydration strategy as well, but it's all in the preparation.  It's difficult to know whether it'll get you all the way there without knowing just how crap your pre-LR nutrition has been, but I reckon you've got every chance of avoiding the wall completely.

You'll most probably fade towards the end anyway, through the good old-fashioned physiological mechanism of being 'bloody knackered' but we wouldn't do it if it wasn't a challenge, eh? 

I was planning a last 18 miler this weekend (2 weeks before race) and then a 2 week taper down.  As for nutrition strategy, I don't really have one and would welcome ideas.  I know nothing more than eating sensibly with a carb rich diet close to the race.  I won't be drinking alcohol and am happy to give myself the best chance I require.

Thanks for the advice. I fully expect to have my leg falling off towards the end, just the later the better!

Yes - try the jelly baby thing on your next long run.  Ideally you'd have done this already - but I think its worth trying.

Gels are the other option and seem to work for me - one every 5 miles.

I tried gels on my 16.3 race every 5 miles water station.  The first 2 everything seemed great but on the last one I washed down a Lucozade gel with Lucozade Sport (it was the only drink they handed out, and I have since found out that this was a useless exercise).  As I started to feel sluggish thereafter I thought maybe I didn't agree with them.

Perhaps will give them another go on Sunday, but properly this time!  As well as Jelly Babies......