This is one of the strangest areas of endurance sports for me, hydration and electrolyte replacement and quite honestly is not something I am sure I have figured out, even after completing 13 Ironmans.
We hear the marketing message being sold by Gatorade, our bodies need all the ingredients that are in their drink - potassium, sodium, calories that are in the carbohydrate form. I do partially believe that our bodies need these in our long workouts which I consider more than 90 minutes.
I am just not sure our bodies "NEED" them, absolutely must have them. I use a brand called Carbo Pro for calories and Skratch Labs for the electrolyte part of the equation and my stomach behaves well with these. I have had nightmarish races where I relied on Gatorade or other brands that were on the course. This is the HATE part of the post. Bad stomach equals bad race!!!!
I do feel the calories being delivered to my body with Carbo Pro helps me in Ironman. I am out there typically for 13+ hours so there is an obvious need for calories.
Where I am wondering if I have been incorrect in their use is in training. Not on the long days where calorie ingestion is critical but in shorter workouts. Historically I have even used them in very short workouts. This is going to change over the winter. I am going "Paleo" in my training nutrition in that I will rely on only water and food for short to medium workouts.
The other benefit that I see that may happen is a slight weight loss and better fat adaptation. Stay tuned on that, I will update you as I go. I am currently weighing 181.6 as I woke up today and I am trying to really bring that down over the winter.