fish that are fed will grow faster but IIRC the information that I've read here, ultimately they will not grow any larger than fish that are not fed. The "fed" fish will just get there quicker. (If I'm wrong, experts please feel free to correct me).
I must disagree (until the experts chime in).
Condello always says that "Mr. Opportunist" who eats both plentiful natural forage AND chows down on pellets grows bigger than "Mr. Natural " (who won't eat pellets) or "The Pellet Pig" (won't eat anything else).
Various Pros & PMs point out that fish have a finite lifespan, and while growth can resume following a period of poor diet, the growth that might have been attained during that time is lost for good.
P.S. If a non-feeding philosophy is right for your goals, desires, or situation, go for it. Your non-fed pond with beau coup forage could produce bigger fish than a fed pond with no natural feed. But great forage + feeding will produce the most or the biggest fish (depending on management) IMHO.
P.P.S. One must be much more careful of water quality when one is feeding.