[pikma]

There's another thread linking the same article, and it's very unclear that this loss of weight is caused by the mental effort.

If thinking hard required a lot of energy, wouldn't we expect that thinking hard would cause an increased heart rate and faster breathing?

[sva_]

It is a bit confusing to me because it is often said that the brain draws about the same amount of energy, no matter what. Perhaps people also eat less during tournaments.