Totally. You can kind of "fake it" in a 70.3, but not in an IM

I've never worked with someone who's had to mix up drinks at aid stations - only ever pre-mixed. Don't want to have to mess with that mess during a race. Happy to help dial in your approach as you approach your next race.

Are you calling out to eat with your mind?

Psychologically speaking - how are you communicating with your stomach? If you think of the incoming food and gels on the run as good and needed and tasty and focus on the food, your stomach may turn around. Just a thought.

I tried morse code, don't think it worked ;)

I've always had sensitive stomach when running. This weekend completed my sixth IM in hot/humid conditions and again my stomach was the limiting factor. I feel I could have dropped a good 10 minutes from the run if I was not in so much pain. My legs felt fine, my HR was spot on, I wasn't working very hard.

I reduced my race food intake over the years trying to address this; this year it was pasta dinner night before, 3 Ensures (350cals each) at 4 am, about 900 calories on 5 hour bike (banana bread and gels) and only water on the run. I'm at fatmax @190np so not digging into glycogen stores too much and good with energy level throughout the race (this is third IM where I take no nutrition on the run and I'm not close to bonking). Felt good on the bike but my stomach hurt badly on the run and I could barely even get water in.
The standard advice (train your gut for 300 cals/hour), just does not work for me. I eat the same as race day with no issues on long training days, don't see any "training" happening.

Anyone has similar experience or ideas how to fix this, or should I just accept the fact that I don't have the stomach for long distance racing?

thanks

Hi Doron,

IME, Maltodextrin is a game-changer (to keep osmolality within optimal range in the heat). I would highly recommend trying the next with your core nutrition based around pure maltodextrin.

Other factor to look at would be concentration. In the heat, keeping your mix to ~6% by establishing a good water base early is important for athletes with a history of gut 'shut down'.

A few more thoughts on the optimal mix for hot weather races here... https://alancouzens.com/blog/hot_nutrition.html

Also, what is your fat burn (in kcal/min) at race power?

Best,

Thanks Alan, this is great stuff.
Your article is very helpful. I read it a while ago, but stupidly didn't really treat my race-day nutrition scientifically and pragmatic enough. I only played with the carbs quantities and experimented with various products, but always got similar results.
I will definitely pay attention to osmolality and beef up sodium dramatically (I only took about 1,000mg through the whole race).

As for fat burning, based on Inscyd test I did in Feb, at Fatmax (~200w), which is roughly my race power, I'm burning about 120 g/h of fat and 60 g/h carbs.

Alan, as always you rock - your questions are spot on and I think I know what went wrong.
The issue is not energy - I burn enough fat to do a sub 10 hot/humid IM while taking in ~1,600 cals. I suspect the issue is osmolality - half of these calories I took in the morning with ensure bottles, and if I was to keep proper osmolality I would have to drink ~3 bottles of water (which of course I didn't). So the ensure just set there like a sludgy time bomb blocking my stomach and as soon as I hit the run it was game over. It wasn't the run, I was screwed at 4am!

Some side notes:
- DYI 2:1 maltodextrin/fructose is at least 1/3 the cost (per calorie) of any sports drink I could find. And as you say, its hard to find a sports drink that uses maltodextrin (I could only find Hammer nutrition, but they don't mix it with other sugar source)
- I also doubt the validity of extrapolating your metabolic efficiency from a CP curve, but I am surprised how big a difference it is from what you saw with direct measurements. It could potentially lead people to very bad nutrition planning and bonking on race day.

3 Ensures (350cals each) at 4 am

Whoa.