Simply by the volume of research in the field of athletic performance - Physiology shows the cellular processes that make human physiology the same, is vastly larger than any body of evidence that show us to be any measure different from one another. There are some differences that physiologically separate us yes; however, if you swim, bike, run, like every other creature that calls themself an athlete - you create ATP from glucose, and the other sugar - "...oses".
I have never put whey powder in my bottle during a ride. Soy, yes. For years. Never had a deleterious effect on a ride. If whey were what was available, I'd use that.
I have used both at one time or another in a recovery role. Always positive. No side effects.
I use the gels too. One over another, or one better than another? "BOO!" (Italian for -Who cares!)
"When" you use an energy source on long efforts, is more important than "what".
In all seriousness... I prefer Snickers!!! Trained and depleted - I'll give ya another solid hour with a Snickers and a 20oz. sport drink, or a sport drink with a scoop of "magic powder" (soy/whey) either doesn't matter when the hammer drops!
The powders are for gastric emptying, and absorption rates in order to facilitate recovery.
I take a large can with me to Italia, mix it with their Gatorade as soon as we are done.

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