How is a custom formula not controlled??? It’s far more controllable than being wedded to pre-determined calorie/electrolyte mixes picked by the gel manufacturer.
If it’s really hot and I need more fluids with electrolyte I don’t necessarily need more carb/sugar/fat/whatever just because I need more fluids. Body won’t process more of each thing for power, per unit time. So combining your fluids and your “food” IMO cripples your flexibility to do what you need to do.
If I can take in XXg of carb per hour but I need XX liters fluids per hour, why am I going to consume twice my carb just because I thought it a good idea to pre-mix it all together? That’s silly.
If you are going to do that, carry separate bottles. Mix and plain water. Even then, that’s more complicated than it has to be.
If this was “such a thing” then the guys riding for 3 weeks in the heat of summer in July in France and summer in Spain wouldn’t get mussette bags and still eat gels and constantly use domestiques to ferry fluids to riders. The limitation in tri being you don’t get mussette bags and breaks to “sit up and eat” due to losing time and no outside help I think creates a problem nobody needed a solution to. The guise of saving time by throwing all of it into one bottle doesn’t really fit the model of taking in the right combo of fluid replenishment for maintaining body temperature and salts/electrolyte and replenishing energy stores.
For something like a sprint tri or a duathlon bike leg, sure. Combine it. You only need one bottle on the bike anyway so why not have it in the same single bottle. But as soon as the heat outside is more than a bottle an hour, what are you going to do? Mix up more of your “all in one” junk at every water station after you run out?
In one hot over-100 mi and over 12k feet ride I went through probably 10 bottles. Over two bottles an hour. Still lost a lot of weight too. I’m expected to carry and mix up my crap after the first bottles are gone? Lol, no. I carried my gel arsenal in the leg grippers of my kit, had a pair of bananas in my kit pockets with a couple Cliff bars.
On a tri bike you can have a bento box, bta bottle, and bts bottles…use it. And I’d rather eat a known gel than depend on taking the right amount of sips from some bottle I made. What is it? 1/3 bottle per hour? 1/2? One?
Single sport folks might be given crap by long course triathletes…but we’ve got a good grip on “challenge” events where you’re on-course for around 8 hours and have to manage nutrition for that long.
Not sure what you are saying here, all pro tour teams mix nutrition in some of their bottles in combination with gels. SIS beta fuel that won froome the giro was mixed in a bottle. Its not actually that hard to keep track even for long events. Start with one bottle with concentrated 2-3x and water or 1x mix in the other. Drink part of the bottle and refill and/or swap out and then supplement further with gels/solid food etc. Easier to get plain water out on the road. I’ve gone through at least a dozen bottles with this combo on hot double century rides. Beats trying to carry like 15 gels