Did you, in addition to training for the triathlon change your diet? I tried it both ways (not for a triathlon, but general fitness) 1) Not changing my diet 2

Did you, in addition to training for the triathlon change your diet? I tried it both ways (not for a triathlon, but general fitness) 1) Not changing my diet 2) Changing my diet (less meat, minimal processed food, no coffee, etc.). There was a massive positive difference with 2). IMO, a person's diet is way, way more important than his/her exercise regime.