I worked with an exercise physiologist to put together my training plan for my first marathon; I just followed his direction relatively blindly, since I didn't (don't!) know any better. I have since figured out that his direction is to fuel far more frequently than others seem to be doing. I take one gel every 3 miles with water (since that's usually how far apart the water stations are on the course). Since I have a condition that makes me super sensitive to dehydration, so I double up on the water at each station. It seemed to work for me in January... I have yet to make the wall's acquaintance!

There's no one size fits all approach to fueling (or other aspects of running marathons) and it takes a bit of trial and error to figure out what will works for you. Using your long runs to try out your fueling strategy is a good move but it may take more than a couple of tries to get it right

I thought I had it right with going by mileage but for my last marathon I switched to fueling by time because that was what my training partner was doing and found out that worked out better for me.

That said, I leave you with the advice my husband always give me relative to training. Listen to everyone but do what works best for you.

That said, I leave you with the advice my husband always give me relative to training. Listen to everyone but do what works best for you.

That's some good advice there

I'm still figuring my own self out, so I can't help much, but I figure slightly over fueling is better than underfueling. Running my first 17 miler tomorrow, so it's still a work in progress!

Why are you training at low glycogen levels? Glycogen is an important part of long distance running - it gives you the carbohydrate spark that lights the fat-burning fire during your runs.

The theory is that training on low glycogen levels will stimulate adaptations in the body to burning more fat and less glucose than if you always run with high levels of glycogen. This allows you to better preserve your glycogen stores on race day and reduce chances of hitting the wall. It is debatable as to whether this theory has any merit, but I'm one of those people also putting it to the test to find out. I'm about 2 months in to a marathon training plan and so far it seems to be going well. I ran 16 miles this morning with moderate glycogen store levels and no food or sports drinks during my run. My pace was 15 seconds faster than marathon race pace.

I think this is probably unecessary for elite runners who run like 70+ miles a week to worry about lowering their glycogen stores because they are inevitably going to occasionally run while low on glycogen just by the mere frequency they run. Someone like me who only runs about 4 days a week is always fresh, so I have to manually lower my glycogen levels through a low-carb diet to simulate the same effect.