All of these points are interesting.
I feel like in shorter sessions <2.5hr I used to be able to get away with very high concentrations of High 5 Energy Source and smash a load of SIS gels on top, taking on loads of energy. But I guess over 150mins I’m starting out hydrated so my body has enough fluid to buffer the carb load.
A tougher 3hr session such as 2x20mins sweet spot, then 4x3mins at 120% then 50mins 80-85%, on a warmer day, hydration became an issue. Equally a typical 4hr ride of generally mid z2 with 60mins of sweet spot sprinkled in, hydration is definitely a problem. As @cwiggum mentioned the guts start to go. Energy can’t be considered in isolation and hydration has to be factored, for me anyway.
Part of what has led me down trying to get my head round all of this is, as I mentioned I ‘used’ to be able to tolerate high concentrations but as of late I think I’ve broken something! The day after taking even a 5-6% solution my guts ache. It’s really bizarre. I’m trying to figure out if it’s a fructose malabsorption thing. Did I break my GLUT5??? I really hope not
But again, on the commercial point, if Maurten/Beta Fuel are just more of the same, why isn’t everyone offering it?