Not a complaint…
Just comparing some of the cals, carbs, electrolyte numbers of mortal vs other popular drinks like EFS, Gatorade endurance, etc.
Am I correct in saying that the -main- diff is the lower cals and carbs in Mortal? And if yes, would simply consuming, say, an extra gel per bottle make up for it?
I believe th other issues were very high sodium for the amount of carbs and it also had a stevia sweetener which can be troublesome for some people.
There was a thread on this not too long ago I think that had some good info. Alex Harrison chimed in as well and it’s always worthwhile listening to his thoughts on endurance nutrition.
Yes, you could sub with gels. A lot of the controversy is that IM basically swapped out a calorie replacement drink for an electrolyte replacement one. Since Mortal is sweetened, there was a chance that folks would use it the way they had used Gatorade Endurance and underfuel/bonk.
Some folks (ex. Lionel) did the whole race on Gatorade, and with Mortal it’s no longer possible to live off the course in this way.
As the PP mentioned, there is a great thread on this with some leaders in the field weighting in.
yes Dr H has some great advice. Basically you need salt (sodium as in salt or sodium citrate) and sugar… maybe maltodextrin to smooth out stomach issues. These electrolyte drinks are not worth the $. Another good source of info is Asker Jeukendrup.
In concept, yes, in practice, it’s a little more complicated. What is important to know is how many grams of carbs and sodium per hour you need, and how many you can handle (and play nice with your body/guts). Once you get a grasp on that you should be able to factor out what you can and can’t supplement.
Different sources can correlate to different tolerances for some people. For example, I can handle higher concentrations of carbs if it’s cluster dextrin than I can handle if it’s maltodextrin, because the maltodextrin starts to give me gi issues. I can handle more sodium citrate than I can sodium chloride for the same issues. I can stomach higher concentrations of carbs and sodium on the bike than I can on the run. Some people can run on Dr Harrison’s recipe of straight table sugar. This is all important to discover in your build phase and race prep phase to prevent blowing up on race day or developing gut issues.
Precision hydration has a free survey/calculator that can help give you an idea of what numbers you should target for a race so long as you feel confident in your answers to the questions. As mentioned before, Dr Harrison’s posts on slowtwitch are a great resource. If you’re not practicing this targets now and experimenting with course nutrition you’re asking for trouble on race day. This year I started carrying all of my own course nutrition outside of plain water and coke (if I need it toward the end of the run), and I have found my performance to be more reliable. I know it’s not ideal to carry a water bottle on the run, but timing my own intake on my own terms, with what works well for me, and just throwing it when I’m tired of carrying it has been a huge help.
I actually do use precision hydration and have used their online tool to estimate what I need. That said, I would say I’ve always followed a somewhat generic plan…knock on wood I’ve never had any gut issues with any of this sports drink/gels/whatever stuff.
Usually on the IM bike, I aim for roughly 300 - 400 cals per hour, which usually would be 1-1.5 bottles of whatever sport drink I use (Usually precision lately), and 2 precision gels.
I start with 2 of my own bottles on the bike, and have 2 in special needs. I then usually also grab a couple bottles each 90km from aid stations. So I guess I’m thinking for that 3rd and 4th bottle on each 90km from the stations, I’ll down an extra gel or two…
How did Mark, Dave, not to mention all the age groupers, survive Ironman events back in the 80’s without all these special products??? 
They survived back then because it was a smaller pool of participants who likely had the natural/genetic/athletic-background advantage. Now anyone/everyone is out there; and I am not saying that’s a bad thing because I put myself in the not-so-gifted-so-I-have-to-work-harder category. I raced with a guy last year who barely did anything to prepare and went sub-6 on his first race without any structured plan. Some people can just do it, and that’s who did it back then.