As much respect as I have for triathletes, they aren't really representative. Food choices are incredibly important for athletes in weight class-limited sports (eg wrestling) or where muscular hypertrophy is important (eg powerlifting). Gymnastics is another one. Believe me when I tell you that coaches have diet absolutely dialed in for many classes of athlete.

Is this actually a disagreement, though? Doing a hyper-specific sport act like that is much less natural than being a triathlete.