a runner who for his entire lifetime stayed away from non-salty foods or who stayed away from non-sugar foods his whole life?
who would be faster? if all other factors were kept equal (genetics, training, etc.)
what about one who pigs out on broccoli all of the time vs one who pigs out on licorice all of the time.
I'm guessing the low-sugar diet would be more beneficial to athletics than the low-salt diet. I would also guess that lots of broccoli would be more positive than lots of licorice. But either way, the impact would be minor.