Curious question about IM and really long races

Yeah, it can be a long day - but you'd be surprised.  An ironman will typically have things like orange slice, pretzels, and warm chicken broth on the run course in addition to the gels, chews, sports drink.  The other big one is flat coke.  You do have to practice and plan your nutrition for the day.  Honestly, if you do it right you're fine. I think i had one cup of chicken broth on the IM run in addition to gels/sports drink/water (which were my planned nutrition (and it was because I was cold due to some rain that had fallen (and i was just getting tired of my gels) not because I was particularly hungry.

Also, in Ironman  races you can pack 'special needs' bags - one for the bike and one for the run - a lot of people put in chocolate bars or other sweet treats as a pick me up. You can grab them around the middle of each.

But then there's always the post-race food to look forward to!!! At Ironman Mont Tremblant (the one I did) there was beer and poutine and subway sandwiches and things.   Very satisfying at the end of a long day but I wasn't particularly starving.

17 hours

I drank Infinit and ate clif bars on the bike, lived off the course on the run. I was not hungry for the post race food. Got back to where I was staying and thought I would be really hungry, nope, got a few bites down then gave up and went to bed. Your stomach really ends up being very full at the end of the IM (or at least mine did). Now the next day... that was a different story, had PLENTY to eat the next day.

Nutrition is a key element for any endurance race. Check out the Iron-Distance forum for lots of questions and answers on this topic. But a typical race-day nutrition strategy would include 1 or 2 breakfasts pre-race, 200-400 calories per hour on the bike, and 100-200 calories per hour on the run. For many people, stomach and GI issues will dictate what the body can absorb, so sometimes nutrition plans get thrown out the window. 

Races themselves will provide water, sports drink, Coke, broth, gels, chews, fruit, candy, chips, etc. at aid stations during both the bike and run. Anything else is up to the athlete to carry. Most people find gels and sports drinks the most convenient and easiest to digest - so that's what a lot of people gravitate towards. Others find success with more "real" foods - I've seen sandwiches, boiled potatoes, yogurt, all sorts of things. It really comes down to what works for you individually.

There are plenty of porta potties in iron-distance events, just like any other race. 

And it's 17 hours

If it were 19 hours, I'd be right there with you toting a meal in a rucksack...

Thankfully, the cutoff is 17 hours.  

Most people target 200-300 calories/hour during the race which replenishes about 1/3 of the calories expended.  In the IM training forum, there is a current discussion about nutrition for IM events.  

Now if you really want to see some amazing things, take a look at ultramarathons. or "outdoor buffets" as I call them.  Burgers, soup, potatoes, sandwiches, cookies, candy, pizza, along with the usual fruit, bagels, peanut butter, and sports drink.  

I'm usually ready to chow down after the race too!  

You are saying an athlete burns 600-900 calories an hour in IM? I am surprised it is that high!

I typically burn about 600/hr during my training rides/runs, and I typically train close to my IM pace...  900 maybe for the elite athletes that are really cooking... so 600-900 doesn't seem unreasonable.

I had a chuckle at calorie count on my HRM after the race.  It stopped counting after it hit10k calories burned...  Actually, it read 9999, because they didn't have room for the extra digit on the display.

I just finished an Ironman 3 days ago and with the amount of food on course (and what I carried) I finished the race not even the least bit hungry, not GI issues just full (actually not even especially hungry the day after either).

But in addition to the huge amount (and diversity) of food available on course you actually do have 4 opportunities for an actual sit down meal:

-After the swim, before the bike

-Half way through the bike

-After the bike, before the run

-Half way through the run

At any one of those 4 points you can have a full meal of whatever you want that you are allowed to bring to the race beforehand and leave waiting for yourself.

Would I recommend doing that? No. Did I? Definitely not.  But you certainly could, so there is no risk of going hungry.