R3261
get an athlete to spend a considerable amount of money on a similiar product, combine it with your consultation fee and expertise telling them it is going to do x better, root it in the OCD nature of sport and that's a mighty tasty bowl of placebo
You seem to have a skewed picture of the enviroment.
The majority of sports nutrition packages aren't delivered like this and the one-to-one work in clinic is not something you would use to form an opinion due to the diverse range of individuals, demands, lifestyles etc, again it's like n=1.
No, the above might be true if half the time they new what they were getting (or understood or cared) or, indeed, paying out of their own pocket for my services, it's more like
'there's shakers provided, this one has my name printed on it, I'll drink it'. Med/Sci teams are there to think about this so the athlete and even coaches don't have to.
As for possible mechanisms, I don't know, there's a variety of things you'd look at. Many who benefit also seem to get ill less often which you would expect to be a significant factor in performance and stats improvements but that throws up more questions than answers....
Hopefully one day we will have some answers but the amount of money available for research unconnected with interested parties as you know is small, so we go on relying on a little research here and there and inferences from other areas.