Marathon Training, Lots of Questions

Congrats on making it this far, and for signing up for your first marathon.

1). Eating at so large a deficit is NOT A GOOD IDEA for marathon training. I suspect you know this. I eat very close to maintenance while in training. Often I will not feel like eating back 1800 calories after a 20-mile run, so I tend to switch to TDEE method and spread my calories out over the course of the week. I'm a 5'9, 145lb woman at 22% body fat, and I eat 2700+/day during training. this accounts for about 50 mile run per week. On this diet I will still lose a few pounds during training. If you don't eat enough, first off there is the dreaded 'bonk' - you will feel it on your runs. Secondly, not getting enough protein means losing muscle as your runs get longer and longer. When people talk about running making you 'skinny fat', this is what they mean. Running in and of itself won't, but running without being smart about your nutrition will.

1a) 1300 seems a bit high for a 5 mile run and a 1.5 mile walk, even at 246lbs. Using the standard ".63 x weight x miles" I got a burn of 775 cals for the running.

2). As for what I eat, I make sure to hit my protein first (1g per lb lean body mass). You will be running a lot. You need to have adequate protein for muscle repair. There is a lot of cheese, greek yogurt, lean fish, and eggs in my diet. Runs over 10 miles get a protein shake at the end. I have lots of fresh fruit around at all times. I find that I will crave pineapple or a banana much more than chocolate. That being said, once I've met my macros goals, bring on the Ben and Jerry's.

3) What works during/before runs? That is entirely up to you. I can't run on a full stomach, so usually its an apple or banana with peanut butter an hour or thirty minutes before. For road runs during training I won't eat anything (except a test 20-miler with my energy gels to make sure I won't have any problems). On race day, I take a gel every 6 miles for an added kick. You will have to work out what you like on your training runs.

4) Cross training - STRENGTH! Squats, planks, pushups, lunges. It doesn't have to be weighted, but you need to develop those core muscles and keep your glutes, hammies, and quads strong to avoid injury.

5) Eating the week before is personal as well. Don't eat anything strange the day before the race. Stay away from high fiber and spicy foods. Carb loading doesn't mean stuffing your face the night before - that would be a bad idea. Up your carb intake 2-3 days before the race, then eat 'normally' the night before. You don't want to be weighed down on race day. There are a ton of glycogen-loading strategies out there, but for your first 26.2, don't over think it.

As far as other things go, just get a plan and stick to it. You will get sick. You will miss a run. It will be fine. Don't increase too fast (10% mileage increase per week). Invest in some body glide. Good luck!

I wish I had more time to give you a good answer but I am pressed for time at work. Vmclach has some good advice, I suggest joining the "Long Distance Runners" group here on MFP for more specific running advice.

My $.02 - you should NOT be in a hurry to run a marathon. Get at least few halfs under your belt and really learn how to run and race.

Having done 26 marathons, I can't being to explain how important miles, miles and more miles are when STARTING your marathon training.

Indeed there will be people who have started marathon training the week after their first 5k, but those marathons rarely end well.

Happy running!

I've probably been in a similar situation to OP. I started running 3 years ago and lost 30kgs over the first year. My first goal was to run a 5k, then 10k, then half, then full. It took me16 months to go from a fat lazy *kitten* to running my first full. And going further appealed because Im not fast, and it just seemed logical to keep going far.
To begin with, i was really into my calorie goals, hitting macros and all that stuff. I've stopped monitoring that so closely, and i generally maintain- even though i could still benefit to drop another 15kgs.
You can do it. I can't tell you about what your cals should be because i don't get what mine do! But you'll know what you need as you start to crank out more miles and crank up the intensity.
I eat quite specifically when i'm training for a full. My training consists of 2 short runs (3-6 miles), a mid run (6-10 miles) and a long run (up to 22 miles). I also do squats, lunges, planks, donkey kicks, bridges, clams, press ups, weights- anything that will help my core. I find that when i dont do these, i end up running shlumpy after a few miles. Ive also noted that with increased thigh type exercises, my stride is longer and form seems better, and therefore distance runs are less painful.
Diet-wise, i avoid spicy foods for 2-3 days before long runs. I'm conscious of how mug veg and fruit i have. I plan my route so that within 20 mins of leaving the house for every run, i'm at a toilet. i picked up an elliptical trainer off the internet for $20- it's from 1976, but that doesn't matter. I have it as an emergency back up. if the weather is too bad or its too late to go for a run, then i can always go on that for 45 mins (which replaces a short run), or about an hour (to replace a mid run). Not used to replace a long run.
clothes are important over long runs. running tights are important, but a long sleeved compression top is vital to stop chafing around the bingo wings (upper arms)- otherwise your tshirt rubs right there and it's so painful. also need to vaseline underneath your well fitting sports bra.

Generally, as you go you will find out what works for you. we're all different. but you have some good tips here. And FWIW my next full is on 3rd may! it's a repeat of my 1st full last year. We'll be training buddies!

I like hal higdons marathon training plan. i'll be using that again, although the jeff galloway method sounds like it might be good for me this time.

Some advice from a hack runner...

To train I ran 18 to 22 miles per week for several months. That's it, no other prep with food or anything. On the big day it took 5 hours to finish and I hit the wall at 18 miles or so (but still was able to run plenty during the last 8 miles). I tried anti chafing stuff but it did not work so many parts were very raw after. One other thing, I signed up on impulse the day before event (never planned to run so I was not really training for anything)

Good luck