Interesting. I had heard that chess players burn a crazy amount of calories during tournament matches, but when I looked it up just now it seems like that isn't true: https://statmodeling.stat.columbia.edu/2025/06/30/its-sapols...

The original claim is not wrong. Thinking hard does not burn significantly more calories.

If it’s really hard to measure because the amount is so small that it requires precise equipment, it’s not significant relative to the rest of the body’s energy expenditure.