The ESPN article had a misleading title. They go on to say that a player burns 6000 calories a day , but Caruana runs an hour a day (or more). These Grandmasters are not reaching into some esoteric mental ability and burning more calories that way; if anyone has ever seen a Grandmaster play against many players at once, or blindfolded (or even blindfolded and against many players!) one can really understand that they see the board in a way that's pretty different from us.
The classical theory for this is that they have formed bigger/better chunks than us from excessive playing (the very same way a Mathematician or a Basketball player does). Calorie consumption, is thus correlation in that specific context.
Although, I think, a (weak) connection could be made between the use of Language and these chunks formations or using this chunks (who's to say this is not a specialized use of Language?) for the context of a tournament, but I have yet to see anything that support this idea.
In light of reading Hazard's Shortform Feed -- which I really enjoy -- based on Raemon's Shortform feed, I'm making my own. There be thoughts here. Hopefully, this will also get me posting more.