Ice Age 50 fueling by the numbers & Kettle 100 mile experiment on deck…

I’m not sure I was completely recovered from the effort of a road-100k only 4 weeks before and I knew most of my training had been road and track, leaving me a little wary of how “trail-ready” my legs would be.    On the positive, however, my race-fueling plan at Mad City 100k had gone well - This gave me confidence as I went into the Ice Age 50 mile that I could at least control one variable of the many that have to go right to make any ultra event a personal success. 

I used the same strategy as Mad City, although I waited a bit longer to start introducing calories this time.  I didn’t carry water or take calories until I hit Hwy 20 at around 17 miles.  There I had a single scoop of Orange Vanilla Perpetuem (164 calories) dissolved in around 4 oz of water and picked up a hand-held bottle with just water in it.  I repeated this at Rice Lake, in-bound at Easterly Rd., and Hwy 20 again. 

This proved to be too many calories in a short time and I got a little bloat feeling after taking in 164 x 4 = 656 calories in the space of 9 miles.  At Mad City I took 164 calories every 10k, but in this short span at Ice Age, I took that same “dose” 4 times in 72 minutes.   I continued with just water from that point and didn’t take any more calories until I hit the aid-station at mile 37.  Here I didn’t feel any bonk or a specific need for calories, but I tried some Mountain Dew to see if the caffeine might give me a spark with just 13 to go.  I took Mountain Dew again on the way back at mile 43, but it didn’t seem to give me any real boost, so I just drank water the rest of the way. 

My finish time was 14 minutes faster than last year and I did it way more comfortably.  Except for that short span where I felt a little bloated, my stomach felt great the whole way and my energy and demeanor were positive from start to finish.  I ended up moving up through the field during the day, not because I was really catching anyone, but because there was some carnage out front and increased temps late in the race seemed to take a toll. 

With just taking around 825 calories over the course of the race, my stomach didn’t require much blood volume to process nutrition and it left my body able to concentrate on keeping blood-flow to my legs and keeping hydrated. 

I have the Kettle 100 coming up in two weeks (just 4 weeks between races again) and I am hopeful that this fueling/hydration plan will continue to work for me.  With the slower pace of a 100 mile, my plan is to drink only water and not take in calories until I am physically hungry.  In the past, forcing calories early has resulted in a wonky stomach and made hydration a bit of challenge.  It is always warm running across the prairies twice in the first 50 miles and dealing with that potential heat makes hydration my priority over calorie intake.

Based on my FASTER study data, I should not be utilizing any muscle glycogen stores as long as I keep my pace slower than lactate threshold levels, which for me should be around 8:30 pace on the trails.  I really have no business running faster than that at any point in a 100 anyway, so that shouldn’t be an issue. 

With 100 miles and an expected 100-calorie expenditure a mile, I should need to burn through 10,000 calories of body fat.    Fortunately, I should have in excess of 30,000 calories on board – based on this calculation:

I weigh 130lbs and have 6.7% body fat according to the FASTER study Dexa scan –

130 x .067 = 8.71lbs of body fat.   At 454 g per pound, that amounts to 8.71 x 454g = 3954g of fat on board.   Calories from a gram of fat have been measured at between 8-9calories per gram, so even at 8, there should be 3954g x 8cal = 31,632 calories stored as body fat.

Keep in mind, however, each person’s body has a threshold at which it will maintain a minimum body fat percentage and will cannibalize muscle before it will dip below that established floor.   I have no idea what my personal “floor” level is, so I just have to hope that dipping into roughly a 1/3 of my total body fat stores doesn’t force me to flirt with this threshold. 

I am NOT committed to denying myself calories during the race – I just want to avoid taking in calories before my body asks for them.  Too often I have ignored the signals that my calorie intake has been excessive for my system to handle under a load and it has caused a myriad of other problems.  It is WAY easier to take in extra calories later than to fix a sour stomach during a race.  Hopefully these theories continue to hold-up and I can have confidence that this is one variable that I am managing well.