Okay so a random example
Person A has a diet of fast food,high oil foods,fizzy drinks and toast/cereal for breakfast aswell as chocolate/sweets everyday
Person B has a balanced healthy diet and has a very good water intake aswell.
(they both have the same talent/genetics and they share the same training time so natural talent will not affect the results)
Imagine they both eat around 2500 Calories a day from there diets/habits and they both train a sport (basketball,football,boxing etc)
will the guy will the better diet naturally have all round better performance
or will it not really affect sport performance