I just re-read your post, 10 weeks - that's going to be brutal! Get a justgiving on the go and I'm sure plenty on here will sponsor you.
So theres this Farmer, from Wasdale, in the Lakes 42 years of age. Goes to His Doctor, who tells Him He has to stop what He is doing. He has a Heart complaint , which wasnt a good thing for a Hill Farmer. So Joss thinks He will start running to get Fit, thing is He never stopped . Became the greatest long distance runner, England has produced Coast to coast, Pennine way in 48 hours Nevada Classic. Funny thing is, He smoked, Joss Naylor MBE what a Man :yep
He'll have to eat more but you'll notice that when you do a butt-load of steady state work, you'll adapt and notice you don't need as many calories as you'd expect.